AU2019461218B2 - Improved dosage of baloxavir marboxil for pediatric patients - Google Patents

Abstract

The present invention relates to a method for treating an influenza virus infection, wherein said method comprises administering an effective amount of a compound to a patient having an influenza virus infection, wherein the compound has one of the formulae (I) and (II) or is a pharmaceutically acceptable salt thereof, and wherein the following dosage is used: (i) in a patient that is younger than 1 year: (a) if the patient is younger than 4 weeks, then the effective amount is 0.8-1.2 mg/kg body weight, preferably about 1 mg/kg body weight; (b) if the patient is 4 weeks or older but younger than 3 months, then the effective amount is 0.8-1.2 mg/kg body weight, preferably about 1 mg/kg body weight; (c) if the patient is 3 months or older but younger than 12 months, then the effective amount is 1.8-2.2 mg/kg body weight, preferably about 2 mg/kg body weight; (ii) in a patient that is 1 year or older but younger than 12 years: (a) if the patient has a body weight of less than 20 kg, then the effective amount is 1.8-2.2 mg/kg body weight, preferably about 2 mg/kg body weight; or (b) if the patient has a body weight of 20 kg or more, then the effective amount is 35-45 mg, preferably about 40 mg.

Description

WO wo 2021/028024 PCT/EP2019/071699 PCT/EP2019/071699

Improved dosage of baloxavir marboxil for pediatric patients

The present invention relates to a method for treating an influenza virus infection, wherein said

method comprises administering an effective amount of a compound to a patient having an

influenza virus infection, wherein the compound has one of the formulae I and II Il or is a

pharmaceutically acceptable salt thereof, and wherein the following dosage is used: (i) in a patient

that is younger than 1 year: (a) if the patient is younger than 4 weeks, then the effective amount is

0.8-1.2 mg/kg body weight, preferably about 1 mg/kg body weight; (b) if the patient is 4 weeks or

older but younger than 3 months, then the effective amount is 0.8-1.2 mg/kg body weight,

preferably about 1 mg/kg body weight; (c) if the patient is 3 months or older but younger than 12

months, then the effective amount is 1.8-2.2 mg/kg body weight, preferably about 2 mg/kg body

weight; (ii) in a patient that is 1 year or older but younger than 12 years: (a) if the patient has a

body weight of less than 20 kg, then the effective amount is 1.8-2.2 mg/kg body weight, preferably

about 2 mg/kg body weight; or (b) if the patient has a body weight of 20 kg or more, then the

effective amount is 35-45 mg, preferably about 40 mg.

Influenza is an acute respiratory infectious disease caused by a virus of the orthomyxovirus family.

Two forms are known to infect humans, influenza A and B. These viruses cause an acute febrile

infection of the respiratory tract after an incubation period of 1 to 4 days, characterized by the

sudden onset of fever, cough, fatigue, headache, and myalgia. Annual influenza epidemics are

thought to result in between 3 to 5 million cases of severe illness, and between 250,000 and

500,000 deaths every year around the world (WHO fact sheet 211: influenza (seasonal). 2018).

Although the condition is usually self-limiting in healthy adults, it can be associated with substantial

morbidity and occasional mortality in children, the elderly, and the immunocompromised (Paules,

Subbarao. Lancet 2017; 390: 697-708). Children play a central role in the dissemination of

influenza in the community by virtue of their relative serosusceptibility and consequently higher

illness attack rates. In addition to the acute illness, young children are at particular risk of

secondary bacterial infections. Such secondary bacterial infections lead to poor prognosis,

particularly in children. Other serious complications can also develop, including cardiac and

neurological complications. Children develop more severe disease compared with adults, with

higher hospitalization rates particularly in children aged < 5 years (Rotrosen, Neuzil. Pediatr Clin

North Am 2017; 64: 911-36). Although NA inhibitors, such as oseltamivir, zanamivir, and peramivir,

can be used for the treatment of pediatric patients at present, more convenient and potent anti-

influenza virus drugs without restriction of use are needed for the following reasons: 1) zanamivir is

WO wo 2021/028024 PCT/EP2019/071699 PCT/EP2019/071699

2 not licensed for treatment of influenza in very young children due to the difficulty with inhalation in

this group (< 5 or 7 years of age, depending on country), 2) peramivir needs to be intravenously

administered, and 3) oseltamivir requires twice daily (BID) dosing orally for 5 days. In addition, the

efficacy of currently marketed antivirals against preventing complications in pediatric patients has

not been demonstrated.

Baloxavir marboxil is a compound discovered by Shionogi & Co., Ltd. that exerts antiviral effects

against influenza. Baloxavir marboxil (also referred to as S-033188, Shionogi Compound

Identification Number) is a pro-drug that is converted to the active form baloxavir (also referred to

as S-033447, Shionogi Compound Identification Number) in the blood, liver, and small intestine

through a metabolic process called hydrolysis. Baloxavir marboxil acts on the cap-dependent

endonuclease, an enzyme specific to influenza viruses, and inhibits viral cap-snatching, thereby

suppressing the growth of influenza viruses.

Baloxavir marboxil has been tested in several clinical trials. However, it is commonly known that

the results of a given clinical trial cannot be simply transferred to the response of any patient to the

pharmaceutical compound. More specifically, there are several factors that may have significantly

influenced the outcome of the clinical trial, such as the patient population (e.g. adults, pediatrics,

elderly, ethnicity) and the dosing regimen.

For example, it is known that the results of clinical trials on adults cannot be transferred to pediatric

patients. To find a dose that produces the desired therapeutic effect and at which no side effects

occur must be determined separately in minors, even if suitable doses are known for adults.

Finding a dose which is particularly suitable for minors is very important because a young

organism processes drugs very differently from an adult. Newborns, for example, only degrade

drugs slowly because the liver and kidneys are not yet mature. Children over two years of age, on

the other hand, have a faster metabolism and their bodies sometimes excrete the substances more

quickly. Furthermore, medicaments which are usually harmless in adults can be dangerous for

children. For example, the compound acetylsalicylic acid (ASS), which is commonly used by adults

suffering from pain or fever, can trigger the life-threatening Reye syndrome in children, which can

severely damage the brain and the liver. Therefore, clinical trials on adults cannot be used for

determining whether a given compound can be used in minors, even less for finding a suitable

dose of the medicament in minors, children and newborns.

Indeed, the oral clearance of baloxavir (CL/F) was influenced by bodyweight. The lower

bodyweight, the higher CL/F. This relationship suggest that CL/F will increase with age. In a

population pharmacokinetic (PK) analysis based on a Japanese pediatric trial (1618T0822), the

CL/F relationship was defined as follow: CL/F=3.05*(Bodyweight/24.3)0.632 A similar CL/F=3.05*(Bodyweight/24.3)°° A similar impact impact of of bodyweight was observed on the baloxavir apparent volume of distribution. Similarly, a lower central volume of distribution was observed in patients with lower bodyweight (Vc=105*(Bodyweight/24.3)1.03) Due (Vc=105*(Bodyweight/24.3)1°) Due toto this this impact impact ofof bodyweight bodyweight onon PKPK ofof baloxavir, baloxavir, the the dose dose which is used in adults cannot simply be extrapolated for obtaining optimal drug exposure in pediatric patients matching drug exposure of adults in terms of both total area under the plasma concentration-time concentration-time curve (AUC) curve and plasma (AUC) concentration and plasma 72 hours 72 concentration after dosing hours (C72). after dosing (C).

Two phase III clinical trials have been conducted for testing baloxavir marboxil in pediatric patients

from 6 months to 12 years of age in Japan (studies 1618T0822 and 1705T0833). All participants of

these studies had Asian heritage (Japanese) and the highest administered dosage was 40 mg. In

the first study 1618T0822 (also called T0822) tablets of 10mg and 20mg were used. Patients were

dosed per bodyweight as follows: 40 40kg: kg:40 40mg mgdose dose(n=8), (n=8),20 20kg kg- -40 40kg: kg:20 20mg mgdose dose(n=66), (n=66),

10 kg - 20 kg: 10 mg dose (n=31), 5 kg- < 10 kg: 5 mg (n=2). In the second paediatric study in

Japanese patients 1705T0833 (also called T0833) baloxavir marboxil 2% granules were administered to paediatric subjects weighing less than 20 kg and less than 12 years of age. 33

patients aged between 0 and 6 year-old were included in this study. 6 were less than 1 year, 13

between 1 and 3, and 14 were 3 years or older. 12 subjects had bodyweight lower than 10 kg, and

21 had bodyweight lower than 20 kg.

Concern that ethnic differences may affect the medication's safety, efficacy, dosage and dose

regimen in a new region has limited the willingness to rely on foreign clinical data. Indeed, it is

known that the varieties in metabolism of persons having a different ethnicity are associated with

interethnic variation in drug pharmacokinetics (Kim, The Journal of Clinical Pharmacology 44.10

(2004): 1083-1105). It was also known that such interethnic variations particularly exist between

Asians (such as Japanese persons) and white persons (e.g. Caucasians), and can lead to

differences in efficacy and toxicity of a given drug (Kim, The Journal of Clinical Pharmacology

44.10 (2004): 1083-1105). The ICH (International Council for Harmonisation of Technical

Requirements for Pharmaceuticals for Human Use) guidelines E5(R1) defined ethic factors and

their inclusion in multiregional clinical trials (see IHC guideline E5(R1) of February 5, 1998

including corrections of March 11, 1998). For example, the ICH guideline E5 makes clear that

clinical data which has been obtained with patients having a particular heritage cannot simply be

transferred to patients having a different heritage. The reason is that several medical compounds

are sensitive to ethnic factors, which means that ethnic factors (such as genetic polymorphisms)

have significant impact on safety, efficacy, or dose response of the compounds. There are several

examples where the ethnic heritage considerably influenced the response to a drug (Bjornsson,

The Journal of Clinical Pharmacology 43.9 (2003): 943-967). Indeed, interethnic variability in

pharmacokinetics can cause unexpected outcomes such as therapeutic failure, adverse effects,

and toxicity in subjects of different ethnic origin undergoing medical treatment (Kim, The Journal of

Clinical Pharmacology 44.10 (2004): 1083-1105). For example, it is known in the art that a particular 30 Sep 2025

splicing polymorphism in the enzyme UGT2B10 which is common in African populations can greatly increase drug exposure (Fowler, Journal of Pharmacology and Experimental Therapeutics 352.2 (2015): 358-367). This UGT2B10 splice site mutation is almost unrepresented in Caucasians (Fowler, Journal of Pharmacology and Experimental Therapeutics 352.2 (2015): 358-367). Similarly, a clinical study on the treatment of gastric cancer with bevacizumab showed regional differences in efficacy 22051576_1 (GHMatters) P118017.AU

outcomes (Ohtsu, J Clin Oncol 29.30 (2011): 3968-3976). 2019461218

In the treatment of influenza it is of high importance to use an appropriate dosage of the anti-influenza drug. For example, a dosage too low can lead to the occurrence of treatment-resistant viruses (e.g. viruses having the I38 amino acid substitution). A dosage too low can further lead to rebound of virus titer or double-peak fever. Therefore, in the treatment of influenza it is of high importance to use a dose of the anti-influenza drug which is as high as necessary for obtaining a fast therapeutic response by avoiding overdose.

As described above, baloxavir marboxil has been tested in various clinical studies in adults as well as in a small number of clinical studies in Asian pediatric patients. However, as also explained above, these data cannot simply be transferred to non-Asian pediatric patients. In addition, as also explained above, usage of the correct dose is of high importance in the treatment of influenza.

Thus, the technical problem underlying the present invention is the provision of an improved dosage of baloxavir marboxil for pediatric patients.

It is to be understood that if any prior art publication is referred to herein, such reference does not constitute an admission that the publication forms a part of the common general knowledge in the art.

Accordingly, the present invention relates to a method for treating an influenza virus infection, wherein said method comprises administering an effective amount of a compound to a patient having an influenza virus infection, wherein the compound has one of the following formulae I and II: (I) (II)

22051576_1 (GHMatters) P118017.AU

22051576_1 (GHMatters) P118017.AU

2019461218 30 Sep 2025

22051576_1 (GHMatters) P118017.AU , 4a

,

WO wo 2021/028024 PCT/EP2019/071699

5 or is a pharmaceutically acceptable salt thereof,

and wherein the following dosage is used:

(i) in a patient that is younger than 1 year:

(a) if the patient is younger than 4 weeks, then the effective amount is 0.8-1.2 mg/kg body

weight, preferably about 1 mg/kg body weight;

(b) if the patient is 4 weeks or older but younger than 3 months, then the effective amount

is 0.8-1.2 mg/kg body weight, preferably about 1 mg/kg body weight;

(c) if the patient is 3 months or older but younger than 12 months, then the effective

amount is 1.8-2.2 mg/kg body weight, preferably about 2 mg/kg body weight;

(ii) in a patient that is 1 year or older but younger than 12 years:

(a) if the patient has a body weight of less than 20 kg, then the effective amount is 1.8-2.2

mg/kg body weight, preferably about 2 mg/kg body weight; or

(b) if the patient has a body weight of 20 kg or more, then the effective amount is 35-45

mg, preferably about 40 mg.

As mentioned above, in the treatment of influenza, a dosage too low can affect the occurrence of

treatment-resistant viruses (e.g. viruses having the 138 I38 amino acid substitution), and can further

lead to rebound of virus titer and double-peak fever. The dosage of the present invention

preferably reduces the occurrence of treatment-resistant viruses (e.g. viruses having the I38 amino

acid substitution) as compared to pediatric baloxavir marboxil dosages of the prior art. In addition,

the dosage of the present invention preferably reduces the occurrence of viral rebound as

compared to pediatric baloxavir marboxil dosages of the prior art. As used herein the term "viral

rebound" means: For observed time points after administration of the compound, influenza virus

titer [log10(TCID50/mL)] at a certain time point is equal to 0.6 or 0.6 greater than that at just before

time point. Furthermore, the dosage of the present invention preferably reduces the occurrence of of

double-peak fever as compared to pediatric baloxavir marboxil dosages of the prior art. The

dosage of the present invention may further shorten the time to alleviation of influenza illness

and/or resolution of fever as compared to pediatric baloxavir marboxil dosages of the prior art.

Es shown in the appended Examples, there was a clear difference in the median time to cessation

of viral shedding between baloxavir (24 hrs) and oseltamivir (76 hrs). These data indicate that

baloxavir-treated patients are no longer infective after a median time of about 1 day compared to

about 3 days in oseltamivir-treated patients. Accordingly, the dosage of the present invention

advantageously reduces transmission of influenza. More specifically, the dosage of the present

invention preferably reduces transmission of the influenza virus of a patient who received the

dosage of the present invention as compared to patients who received oseltamivir. The patient is a

pediatric patient which is newborn or older but younger than 12 years, e.g., 1 year or older but

younger than 12 years.

PCT/EP2019/071699

6

As discussed above, in the treatment of influenza it is of high importance to use an appropriate

dose of the anti-influenza drug which is as high as necessary for preventing occurrence of

treatment-resistant viruses or viral rebound, however, by avoiding overdose. Predicting the suitable

dose of a drug for a desired patient group is an important measure for ensuring that the drug is

administered to the patients in a sufficient dose to obtain the desired therapeutic effect while

avoiding overdose. Such predictions can be performed in silico by using a suitable descriptive or

mechanistic model. Of course, modeling techniques do not provide complete certainty that a given

patient shows the desired response to the tested drug. However, the same holds true for every

clinical testing. Favorable results from biochemical or cell-based assays which test the effects of a

drug as well as animal experiments or even clinical trials involving patients can only increase the

probability that the drug shows the desired therapeutic effects in the subsequently treated patients.

For example, early phase studies usually have a small sample size or may be biased for an

unknown reason, which may lead to an incorrect assessment of the physiological effects of the

drug at issue. It is nearly impossible to absolutely proof that a medicament will (always) show the

desired therapeutic effect in the intended patient group without leading to any unwanted side-

effects. As mentioned, all possible methods for verifying the physiological effects of a drug can only

increase the possibility that the drug will lead to this particular physiological effect in the later on

treated patient. As explained above, predicting a suitable dose of a drug by in silico modeling is is

one of these models, which is particularly useful for establishing a suitable dose for a new patient

group.

In the context of the present invention comprehensive model simulations to predict a suitable dose

of baloxavir marboxil in pediatric patients (preferably non-Asian pediatric patients) have been

performed. The model used for the simulations was developed by considering previous studies

conducted in Japanese pediatric patients. The model integrates both patient's demographics

characteristics and drug PK characteristics in the studied population. Baloxavir plasma

concentrations after various dosing regimen can then be simulated in pediatric patients based on

patient characteristics such as age or bodyweight. Consequently, this model advantageously

provides the basis for a suitable dose of baloxavir marboxil in pediatric patients, preferably non-

Asian (such as white) pediatric patients, which, in all likelihood, ensures baloxavir plasma

exposures comparable to exposures in adult patients and appropriate pharmacologic effect in the

treatment of influenza by avoiding potential side-effects.

More specifically, in the context of the present invention suitable doses for non-Asian (e.g. white,

such as Caucasian) pediatric patients were determined using a modeling and simulation approach.

Based on a model developed in Japanese pediatric patients, plasma concentrations of baloxavir

(S-033447) pharmacokinetics in a non-Asian (e.g. white, such as Caucasian) pediatric population

were simulated for different dosing regimen. More specifically, a population pharmacokinetic analysis had been performed in Japanese pediatric populations by using unpublished pharmacokinetic data obtained in a phase III study involving pediatric patients in Japan

(1618T0822); the suitable dose of baloxavir marboxil for non-Asian pediatric patients was then

obtained by simulating non-Asian pediatric drug exposure after several different dosing regimen,

the ones matching the best adult exposures were then selected. In particular, the simulation of

pediatric drug exposure was performed as described in the following:

With respect to non-Asian pediatric patients that are younger than 1 year, simulations were

performed for 1,000 patients for each age in months for < 2-year old infants (26,000 patients in

total). Thus, several sets of 1000 patients were conducted. For instance, 1000 between 0 and 1

1000 between month, 1000 between 11 and and 22 months, months, for ..for a total a total of of 26000 26000 simulations simulations (i.e. (i.e. 26 26 X 1000). X 1000). ForFor

patients that are between 1 and 12 years old, simulation of non-Asian pediatric drug exposure was

performed for 1,000 patients for every 5-kg body weight for 10- to 60-kg pediatric patients (26,000

patients in total).

In both cases, various dosing regimens were evaluated with respect to their ability to match adult

drug exposure in terms of area under the plasma concentration-time curve (AUC), maximum

plasma concentration (Cmax), plasma (C), plasma concentration concentration 24 24 hours hours after after dosing dosing (C;(C24; acceptable acceptable time time

window: 20 to 28 hours), and 72 hours after dosing (C72). The (C). The optimal optimal dose dose and and appropriate appropriate age age

and bodyweight cut-off were based on a comparison of the simulated drug exposures with those

obtained in the phase III study (1601T0831) for patients receiving 40 mg baloxavir marboxil (body

weight < 80 kg) and patients receiving 80 mg baloxavir marboxil (body weight 80 80kg), kg),those those

obtained in the pediatric phase III study (1618T0822), and those obtained in the phase I thorough

corrected QT interval (QTc) study (1527T0816) for patients receiving 80 mg baloxavir marboxil.

With respect to patients that are younger than 1 year simulations showed that optimal exposure

matching to adults in terms of both total (AUC) and sustained (C72) drug (C) drug exposure exposure was was achieved achieved

with 2 mg/kg in infants of 3 months and older, and 1 mg/kg in younger infants (4 weeks-3 months)

as well as for newborns (0-4 weeks). Accordingly, in patients which are younger than 1 year

baloxavir marboxil can be administered according to the infant's age recorded at the time point

when the when thepatient patientis is diagnosed as having diagnosed an influenza as having virus infection an influenza (i.e., 2 mg/kg virus infection (i.e.,3 2months, mg/kg 13 months, 1

mg/kg < 3 months) to obtain similar exposure of baloxavir (S-033447) to that resulting from the

administration of 40 mg or 80 mg baloxavir marboxil (based on the patient's body weight) to adults

in the phase III and Japanese pediatric phase III studies.

With respect to patients that are 1 to 12 years old simulations showed that optimal exposure

matching to adults in terms of both total (AUC) and sustained (C72) drug (C) drug exposure exposure was was achieved achieved

with 2 mg/kg in children weighing less than 20 kg and flat dosing of 40 mg in children weighing

WO wo 2021/028024 PCT/EP2019/071699 PCT/EP2019/071699 8

20 kg. Accordingly, patients which are 1 to 12 years old baloxavir marboxil can be administered

based to the body weight recorded at the time point when the patient is diagnosed as having an

influenza virus infection (i.e., 2 mg/kg for patients weighing < 20 kg or 40 mg for patients weighing

20kg) 20 kg)to toobtain obtainsimilar similarexposure exposureof ofbaloxavir baloxavir(S-033447) (S-033447)to tothat thatresulting resultingfrom fromthe theadministration administration

of 40 mg or 80 mg baloxavir marboxil (based on body weight) to adults in phase III and Japanese

pediatric phase III studies.

As explained above, the clinical studies which have been conducted with baloxavir marboxil and

Asian pediatric patients cannot be simply transferred to non-Asian (e.g. white, such as Caucasian)

pediatric patients. Therefore, and in order to provide an optimal dose for children younger than 12

years (and therewith improve the chances of these young patients to recover from an influenza

virus infection) an improved dosage schedule for non-Asian (e.g. white) pediatric patients has been

developed in accordance with the present invention. Therefore, in accordance with the present

invention, the patient to be treated may have the racial designation non-Asian, e.g. "white". Thus,

the invention relates to the herein provided method, wherein the patient is white. The term "white"

refers to a person having origins in any of the original peoples of Europe, the Middle East, or North

Africa (cf., e.g., US Food and Drug Administration. "Collection of Race and Ethnicity Data in

Clinical Trials Guidance for Industry and Food and Drug Administration Staff." Issued on October

26 (2016)). For example, the white pediatric patient may be Caucasian.

As described above, the guidelines of the ICH make clear that clinical data which has been

obtained with patients having a particular heritage cannot simply be transferred to patients having

a different heritage. According to the ICH guidelines a clinical trial which has been conducted in

one region (like Japan) cannot be transferred to another region (such as Europe or the United

States). For example, evaluation of the pharmacokinetics in the three major racial groups most

relevant to the ICH regions (Asian, Black, and Caucasian) is critical to the registration of medicines

in the ICH regions. With respect to baloxavir marboxil, clinical trials have been conducted with

pediatric patients in Japan. The present invention is based on the finding of an optimal baloxavir

marboxil dose for non-Asian (e.g. white, such as Caucasian) pediatric patients. Accordingly, in

accordance with the present invention the patient has preferably a non-Asian heritage and is not

living in Asia. Thus, in the present invention the patient may not have an Asian ethnicity. The term

"Asian" refers to a person having origins in any of the original peoples of the Far East, Southeast

Asia, or the Indian subcontinent, including, for example, Cambodia, China, India, Japan, Korea,

Malaysia, Pakistan, the Philippine Islands, Thailand, and Vietnam. (cf., e.g., US Food and Drug

Administration. "Collection of Race and Ethnicity Data in Clinical Trials Guidance for Industry and

Food and Drug Administration Staff." Issued on October 26 (2016)). For example, the patient may

not be Japanese.

Thus, it is preferred that the patient does not have an Asian (e.g. Japanese) ethnicity and does not

live in Asia (e.g. Japan). As mentioned above, a clinical trial with baloxavir marboxil has been

conducted with Japanese pediatric patients (studies 1618T0822 and 1705T0833). However, in

these studies the efficacy of a maximum of 1 mg/kg body weight of baloxavir marboxil was used in

patients aged 6 months to < 12 years. Thus, these Japanese clinical trials are significantly different

from the dosages which are provided herewith, since in the context of the present invention the

patients can be younger than 6 months, and/or receive 2 mg/kg body weight of baloxavir marboxil.

In addition, as explained above, the results of clinical trials cannot be directly transferred from one

ethnicity to another. Therefore, the clinical trials which have been conducted in Japan with Asian

pediatric patients (studies 1618T0822 and 1705T0833) cannot be directly transferred to non-Asian

(e.g. white, such as Caucasian) pediatric patients. As mentioned above, the dosages provided with

the present invention are optimized dosages for non-Asian, (e.g. white, such as Caucasian)

pediatric patients. Therefore, in the present invention it is preferred that the pediatric patients are

white, e.g. Caucasian. Europeans and "white" Americans are usually referred to as "Caucasians"

(Bjornsson, The Journal of Clinical Pharmacology 43.9 (2003): 943-967). Thus, in accordance with

the present invention the patient may have Caucasian (i.e. European or "white" American) heritage

and may be living in Europe or North-America (e.g. in the United States).

Baloxavir marboxil is mostly administered in the form of tablets. However, tablets have the

disadvantages that the acceptability is usually low in pediatric patients, leading to inconsequent

drug intake, splitting out of the drug or vomiting the medicine before it takes effect. In addition,

newborn and young children are often not able to swallow tablets. Also patients with a nasogastric

tube in situ (e.g., intubated patients) are unable to swallow tablets. Therefore, in the context of the

present invention the compound may be administered in the form of a suspension of granules.

Particularly if the patient is younger than 1 year (i.e. patients as defined under (i), above), or if the

patient is 1 year or older and has a body weight of less than 20 kg (i.e. patients as defined under

(ii)(a), above) the compound may be administered in the form of a suspension of granules. For

example, the granules as described in PCT/JP2019/017146 may be used. It has been shown that

such granules (in particular 2% baloxavir marboxil, i.e. S-033188, granules) have bioequivalence

with 20 mg baloxavir marboxil (S-033188) tablets (Clinical Study Report, Study No. 1703T081G,

Shionogi & Co., Ltd.; 2018). Therefore, in the present invention the granules are preferably 2%

baloxavir marboxil (i.e. S-033188) granules.

In the clinical trial with Japanese paediatric patients weighing less than 20 kg (1705T0833)

granules have been used as administration form. The finished granule product configuration

developed for the Japanese market by Shionogi consists of granules packaged in a sachet. The

granules are intended for administration directly into the mouth of the subject. In the context of the

present invention the granules are preferably resuspended (e.g. in a bottle) and a specific volume is given orally (e.g. by a syringe). In particular, the granules to be used in the present invention may be reconstituted with water. For example, 2 g of granules, which contain 40 mg of the compound to be used in the present invention (nominal), may be reconstituted with 20 mL water, which corresponds to a final concentration of 2 mg of the compound per millilitre (mL). These resuspended granules can advantageously be administered to children, even to young children

(infants) and patients having a nasogastric tube.

The granules for oral suspension may have a composition as shown Table 1.

Table 1: Components and composition of baloxavir marboxil granules for oral suspension Nominal Concentration in Granule amount (mg/bottle) (%) Function Quality Standard Component Active Baloxavir Marboxil 40 2 In-house standard ingredient

Mannitol 1120 56 Diluent Ph. Eur./USP/JP Maltitol Diluent Ph. Eur./NF/JPE 700 35 Taste Sodium Chloride 60 3 masking Ph. Eur./USP/JP agent Hypromellose 6 0.3 Dispersant Ph. Eur./USP/JP Povidone Povidone(K(Kvalue: 25)25) value: 20 1 Binder Ph. Eur./USP/JP Silica, Colloidal 40 2 Fluidizer Ph. Eur./NF/JP Anhydrous Sucralose 10 0.5 Sweetener Ph. Eur./NF/JPE Talc 2 0.1 Lubricant Lubricant Ph. Eur./USP/JP Strawberry Flavour 2 0.1 Flavour In-house standard Purified Water Purified Water Vehicle Ph. Eur./USP/JP - - Total Weight b 2,000 100 - - a Purified water is removed during manufacturing process. b An overfill of, e.g. 0.13 g of granules is applied to obtain the targeted maximum extractable

volume of 20 mL after reconstitution; fill weight may be adjusted based on assay value for bulk granules.

Bitter taste has been reported in adult clinical studies with baloxavir marboxil and several

excipients have been included in the formulation to mask the bitter taste and ensure palatability,

such as sodium chloride, sucralose and strawberry flavor. Thus, the granules provided with the

present invention have the advantages that they are to be administered in the form of an oral

suspension and that the bitter taste of the active compound is masked. Accordingly, these granules

improve acceptance of the compound in pediatric patients, which contributes to the achievement of

the therapeutic effect. Indeed, in clinical trials wherein baloxavir marboxil was administered to

pediatric Japanese patients (i.e. studies 1618T0822 and 1705T0833) the most common adverse

event was vomiting. Although the vomiting was considered to be not related to the study drug by

the investigators, reducing or avoiding vomiting which is induced by the administration form can

WO wo 2021/028024 PCT/EP2019/071699 11

provide a therapeutic benefit. In addition, the oral suspension provides flexibility to more precisely

implement weight-based dosing.

As dosing device an oral dosing syringe or an oral dosing cup (both volumetric) may be used to

provide the sufficient degree of accuracy to deliver the recommended doses of the compound to be

used in the present invention (e.g. baloxavir marboxil). For example, a 3 mL oral dosing syringe

that could be used in infants typically includes volumetric demarcations in tenths of a milliliter,

which would be adequate to deliver accurate doses. Alternatively, a 10 mL oral dosing syringe may

be used.

Examples for dosages which may be used are shown below in Table 2.

Table 2. Examples for age/weight dependent dosing

dose volume of 2% suspension Age group weight (kg) (mL) dose regime Age 1 2 3 3 1.5

4 2 5 2.5 1 mg/kg < 3 months 6 6 6 2 mg/kg Infants 7 7 (i.e. young 8 8 children) 9 9 10 10 <12 months 11 11 2 mg/kg 12 12 13 13 14 14 14 15 15 Children 16 16 17 17 18 18 19 19 19 < 20 20 (flat 20 20 20 40 mgmg(flat 40 dose)

The dosing shown in Table 2, above, is merely an example. For example, the dosage of patients

as defined in the inventive method under item (i), above, (i.e. patients who are younger than 1

year) is performed according to their age (e.g., 1 mg/kg for patients who are younger than 3

months; and 2 mg/kg for patients who are 3 months or older but younger than 12 months). For

WO wo 2021/028024 PCT/EP2019/071699 PCT/EP2019/071699 12

example, a child who is younger than 3 months and has a body weight of 6 kg would receive about

1 mg/kg of the compound.

As described above, the compound to be used in the present invention can be administered in the

form of a suspension of granules. Such granules for oral suspension can be reconstituted with

water to provide the desired dose. However, according to the present invention a patient who is 1

year old or older and has a body weight of 20 kg or more (i.e. the patient as defined in item (ii)(b),

above) receives a 40 mg flat dose of the compound. This 40 mg dose is preferably administered in

the form of a tablet. For example, the 40 mg dose may be administered in the form of a film-coated

tablet.

However, the invention is not limited to any specific route of administration of the compound to be

used herein. All possible routes of administration that the attending physician deems useful or

necessary are within the scope of the present invention. For example, the compound may be

administered oral, rectal, nasal, topical, intradermal, as aerosol, vaginal, or parenteral, such as

intramuscular, intravenous, subcutaneous, intraarterial, or intracardial. It is preferred that the

compound is orally administered. Dosage forms for oral administration include coated and

uncoated tablets, soft gelatin capsules, hard gelatin capsules, lozenges, troches, solutions,

emulsions, suspensions, syrups, elixirs, powders and granules for reconstitution, dispersible

powders and granules, medicated gums, chewing tablets and effervescent tablets. Dosage forms

for parenteral administration include solutions, emulsions, suspensions, dispersions and powders

and granules for reconstitution. Dosage forms for rectal and vaginal administration include

suppositories and ovula. Dosage forms for nasal administration can be administered via inhalation

and insufflation, for example by a metered inhaler. Dosage forms for topical administration include

creams, gels, ointments, salves, patches and transdermal delivery systems. However, it is

preferred in the present invention that the compound is orally administered. It is envisaged in the

present invention that the compound is given as a single dose.

As indicated above, particularly for the patients as defined under (i) and (ii)(a), above, it is

preferred that the compound to be used in the present invention is in the form of the granules for

suspension, and is administered as single oral dose, or as single dose which is administered via a

nasogastric tube. For example, the granules comprising baloxavir marboxil as described above can

be reconstituted with water to provide the desired dose in a suspension. If the patient is 1 1year year

but < 12 years and has a body weight of 20 kg or more (i.e. the patient as defined in (ii)(b), above),

then the effective amount of the compound to be used herein is 35-45 mg, preferably about 40 mg.

For these patients administration of two 20 mg tablets or one 40 mg tablet as single oral dose is

preferred.

WO wo 2021/028024 PCT/EP2019/071699 13

Children usually reach 20 kg with the age of about 3 to 8 years, mostly between 5 and 6 years.

Therefore, in the context of the present invention the patient as defined in (ii)(a), above (i.e. the

patient that is 1 year but <12 years, and has a body weight of <20 kg) may have an age between

1 and 8 years, e.g. between 1 and 6 years. For example, the patient as defined under (ii)(a),

above, may be 1 year old or older but younger than 5 years. 1 year old children have usually a

weight between 7 and 13 kg. Therefore, the patient as defined in (ii)(a) may have a body weight

which is about 7 kg or more, e.g. about 11 kg or more.

In the present invention the patient as defined under (ii)(b), above (i.e. the patient that is 1 year

but <12 years, and has a body weight of >20 kg) may 20 kg) may be be 55 years years old old or or older older but but younger younger than than 12 12

years. In addition or alternatively, the patient as defined under (ii)(b), above, may have a body

weight which is less than 40 kg. According to the present invention a patient that is 1 year or older

but younger than 12 years and has a body weight of 20 kg or more is administered with an

effective amount of the compound to be used in the invention which is 35-45 mg, preferably about

40 mg. It is preferred that the compound is administered to this patient in an amount which is more

than 1 mg/kg body weight (e.g. 1.5-2 mg/kg body weight).

In accordance with the present invention a comprehensive simulation has been performed in order

to find optimal doses of baloxavir marboxil for pediatric patients, particularly non-Asian (e.g. white

such as Caucasian) pediatric patients. This simulation shows that the regimen of the present

invention matches adult drug exposure optimally in terms of both total drug exposure as well as

drug levels up to 72 hours after dosing, especially in pediatrics with a body weight less than 25 kg.

Therefore, the patient as defined in item (ii)(b), above (i.e. the patient having a body weight of 20

kg or more) has preferably a body weight which is less than 25 kg.

In the present invention the patient may be healthy except for the influenza virus infection. The

influenza virus may have no substitution in at least one of the genes selected from the viral acidic

polymerase (PA) gene, the viral basic polymerase 1 (PB1) gene, and the viral basic polymerase 2

(PB2) gene. For example, the influenza virus may have no substitution in all of these genes. In a

preferred aspect of the present invention the influenza virus strain does not carry an 138X I38X mutation,

such as the 138T mutation, in the viral acidic polymerase (PA) protein. The 138T mutation is

commonly known in the art and described, e.g., in Omoto, Scientific reports 8.1 (2018): 9633.

Thus, it is preferred that the influenza virus stain does not carry an 138T mutation in the viral acidic

polymerase (PA) protein. The 138T I38T substitution is a mutation in the viral acidic polymerase (PA)

protein of some mutated influenza A strains. The sequence of the PA protein of an influenza A

virus having the 138T mutation is shown in SEQ ID NO:1. Thus, in a preferred aspect of the present

invention the influenza virus strain does not comprise a PA protein having the sequence of SEQ ID

NO:1. It is also preferred that the influenza virus strain does not comprise a PA protein having a

WO wo 2021/028024 PCT/EP2019/071699 PCT/EP2019/071699 14 sequence which has at least 80%, preferably at least 90%, more preferably at least 95%, at least

96%, at least 97%, at least 98%, or at least 99% sequence identity to the sequence of SEQ ID

NO:1 and comprising a substitution (e.g. an I to T substitution) at the position corresponding to

position 138 I38 of SEQ ID NO:1. A fraction of the PA protein of an influenza A virus comprising the

138T mutation is shown in SEQ ID NO:2. Thus, in a preferred aspect of the present invention the

influenza virus strain does not comprise a PA protein comprising the sequence as shown in SEQ

ID NO:2.

In one aspect of the present invention an influenza virus infection is present if the influenza virus

can be detected. The influenza virus may be detected via PCR. In addition or alternatively the

influenza virus may be detected by using an influenza test kit. Rapid Influenza Diagnostic Test

(RIDTs) based on immunologic detection of viral antigen in respiratory secretions offer point of

care (on-site) tests with results available within 30 minutes. Thus, a RIDT may be used for

detecting the influenza virus. RIDTs can identify the presence of influenza A or B viral

nucleoprotein antigens and display the result in a qualitative way (positive vs. negative) (Ali T, Clin

Infect Dis. 2004 Mar 1;38(5):760-2). RIDT assays are ELISA based assays which are less accurate

than PCR, but have the advantage that they are cheaper and faster.

The influenza virus infection may further be detected by using the Roche cobas cobas®Liat® Liat®point pointof ofcare care

(POC) polymerase chain reaction (PCR) system (Chen, Eur J Microbiol Immunol (Bp). 2015;5(4):236-245). The cobas® cobas Liat® Liat® system system enables enables rapid rapid and and accurate accurate diagnosis diagnosis of of influenza influenza AA

or B nasopharyngeal swab specimens. The system comprises the cobas cobas®Liat® Liat®Analyzer Analyzerand andthe the

cobas® Influenza A/B assay. The detection of the influenza virus may also be carried out by using

a PCR-based molecular test (Prodesse ProFlu+ assay, Chen, Eur J Microbiol Immunol (Bp).

2015;5(4):236-245) or the Alere i Influenza A & B rapid PCR system (Merckx, Ann Intern Med.

2017;167(6):394-409).

The influenza virus infection may also be detected by virus culture techniques, which involve

inoculation of clinical specimens onto cell culture lines. By using this method, over 90% of positive

cultures can be detected within 3 days of inoculation (Newton, Journal of clinical microbiology

40.11 (2002): 4353-4356). The influenza virus infection may also be detected via molecular

diagnostic tests, which use detection of viral nucleic acids in clinical specimens to achieve greater

sensitivity than cell culture and in addition allow detection of virus in samples that have lost

viability.

As indicated above, the influenza virus infection may be detected via polymerase chain reaction

(PCR) assays, which allow both qualitative and quantitative assessments in addition to rapid

subtyping of the virus. The PCR detection and quantification of the influenza virus is commonly known in the art. For Example, real-time reverse transcription PCR (RT-PCR) amplification of the influenza matrix gene may be employed as the method for determining the presence or absence, or the quantity of influenza RNA. Influenza virus RNA extraction and purification is a routine technique and can, e.g., be performed by using a MagNA Pure LC 1.0 or 2.0 isolation station

(Roche Applied Science, product # 05197686001). To perform the test, nucleic acids are extracted

from swab specimen aliquots using the MagNA Pure LC isolation station and the MagNA Pure LC

nucleic acid extraction kit according to the manufacturer's instructions (Roche Applied Science).

Reverse transcription and amplification reactions can be set up using Taqman Fast Virus

Mastermix. During clinical analysis, a 4 point (low, middle and high) influenza A and B standard

curve with known virus particles/ml can be used as control and can accompany every run. To

monitor the whole process from isolation to real-time detection, a universal internal control, the

Phocine Distemper Virus (PDV), may be added to each isolate. In addition, to monitor contamination in every isolation a No Amplification Control (NAC) may be included for every PCR

mix that is made. The positive controls must give a positive signal that lies between specified

action limits. If the value of the positive control lies outside the action limit, all samples tested with

the same PCR mix need to be retested. If the negative control gives a positive signal for influenza,

all samples run with the same PCR mix need to be retested. The output of the influenza RT-PCR

assay is what is known as a Cycle threshold, or Ct value and a Ct value is recorded for each test.

The Ct values are converted to quantitative virus particles/ml values with the standard curves ran

concurrent with the samples.

For influenza A positive subjects an influenza A subtype PCR assay can also be performed. More

specifically, for influenza A positive subjects, sub-typing can be performed directly from a subject's

swab sample using a real time RT-PCR assay. RNA can be isolated from clinical isolates as

described above using the Roche MagNA Pure Total Nucleic Acid kit, and can be amplified using a

one-step RT-PCR with influenza A-subtype specific primers. Further methods for the detection of

particular influenza virus subtypes including suitable primer sequences are commonly known in the

art, and described, e.g., in the "WHO information of the molecular detection of influenza viruses" of

July 2017.

Serological tests, such as complement fixation and haemagglutination inhibition, can be used to

establish retrospectively a diagnosis of an influenza virus infection. Because individuals may have

been previously infected with influenza viruses, paired serum specimens, consisting of an acute

serum specimen and a convalescent serum specimen, obtained 28 days later, may be used for

testing.

Most cases of influenza are diagnosed based on compatible clinical symptoms and seasonal

epidemiology. Thus, also the presence of at least one symptom of influenza indicates that an

WO wo 2021/028024 PCT/EP2019/071699 PCT/EP2019/071699 16 influenza virus infection is present. Therefore, in accordance with the present invention the patient

may be diagnosed as having an influenza virus infection:

(i) due to the presence of fever of 38°C or more (tympanic temperature); and at least one respiratory symptom, preferably cough and/or nasal congestion; and/or

(ii) by using an influenza test kit.

Influenza viruses cause an acute febrile infection of the respiratory tract characterized by the

sudden onset of fever, cough, fatigue, headache, and myalgia. The principal clinical presentation of

influenza disease is essentially common between adults and children, characterized by rapid onset

fever and cough, symptoms generally accepted to be directly consequential to viral replication and

the host immune response (innate especially) to viral replication. Beyond the cardinal symptoms of

flu, gastrointestinal symptoms, such as vomiting and/or diarrhea (Minodier, Virology journal 12.1

(2015): 215) can be more common in infants and young children than in adults, and children,

particularly those aged <5 years, may have higher maximum temperatures and higher hospitalisation rates than adults (Paules and Subbarao, 2017, Rotrosen and Neuzil, 2017). For

example, young children usually have temperatures over 39.5°C and may have febrile seizures

(convulsions).

In one aspect of the present invention an influenza virus infection is present if both features apply,

i.e. the influenza virus can be detected, and at least one symptom of an influenza virus infection is

present. Said at least one symptom of an influenza virus infection may be a sudden onset of fever,

cough, fatigue, headache, and myalgia. The symptoms may further include chills, a sore throat

and/or nasal congestion. The symptoms may also include gastrointestinal symptoms. The

diagnosis of influenza may also comprise testing whether the body temperature reaches 38°C to

40°C within 24 hours from the onset of influenza symptoms (Wright, Fields Virology. 5th ed. (2).

Wolters Kluwer Health/Lippincott Williams & Wilkins; 2007. P. 1691-1740; Monto, Arch Intern Med.

2000;160:3243-3247). 2000;160:3243-3247).

In addition or alternatively, the diagnosis of influenza may be confirmed by all of the following:

(a)Fever (a) Fever>38°C 38°C (axillary) in the predose examinations or >4 hours after dosing of antipyretics if

they were taken.

(b) (b)AAt Atleast leastone oneof ofthe thefollowing followinggeneral generalsystemic systemicsymptoms symptomsassociated associatedwith withinfluenza influenzawith withaa

severity of moderate or greater:

(b)-1 Headache;

(b)-2 Feverishness or chills;

(b)-3 Muscle or joint pain;

(b)-4 Fatigue.

PCT/EP2019/071699

17 (c) At least one of the following respiratory symptoms associated with influenza with a severity of

moderate or greater:

(c)-1 Cough;

(c)-2 Sore throat;

(c)-3 Nasal congestion.

(c)-4 Influenza A or B infection confirmed by POC PCR testing.

There are three types of influenza viruses: A, B, and C. Types A and B cause widespread

outbreaks of influenzal illness nearly every year. Influenza C is associated with sporadic, often

asymptomatic infection with little or no mortality and therefore is not of public health concern. In

accordance with the present invention the influenza virus may be an influenza A virus or an

influenza B virus. For example, the influenza virus may be a type A influenza virus. However, the

influenza virus infection may also be a mixed infection involving the influenza A virus as well as the

influenza B virus.

The means and methods provided herein are particularly advantageous if the influenza virus strain

does not have a resistance against the compound to be used in the present invention. However,

the influenza virus strain may have a resistance against other anti-viral drugs (such as peramivir,

laninamivir, oseltamivir, zanamivir, rimantadine, umifenovir or amantadine). Tests for determining

whether a given virus has a resistance against one or more drugs are commonly known in the art

and comprise, e.g., the phenotypic resistance assay and the NA-Star assay, which are both

described below.

The phenotypic resistance assay may be performed as described in the following: Phenotypic

resistance assays (spot/focus reduction assay) can be performed by using the sensitive Virospot

detection technology which combines classic virus culture in multi-well microtiter plates and virus-

specific immunostaining with automated imaging, detection of infected cells using a CTL

Immunospot UV analyzer equipped with Biospot analysis software. The Virospot technology

platform determines sensitivity of virus isolates to antiviral drugs measuring IC50/IC90- In brief, IC/IC. In brief, the the

method is based on inoculation of infectious virus on MDCK cell monolayers in 96-well plates in the

presence of a drug concentration range. After incubation the cells are fixed and immunostained

with virus-specific antibodies followed with TrueBlue substrate and image capture using the UV

Analyzer.

The NA-Star assay is particularly useful for determining phenotypic resistance to neuraminidase

inhibitors (such as, e.g. oseltamivir), and can be performed as follows: This assay uses a

chemiluminescent substrate for highly sensitive detection of neuraminidase enzyme activity.

Neuraminidase activity yields a luminescent compound which is quantified by using a reader. Virus

WO wo 2021/028024 PCT/EP2019/071699 PCT/EP2019/071699 18

neuraminidase activity is determined in the presence of serial dilutions of the neuraminidase

inhibitor. Sensitivity to neuraminidase inhibitor is expressed as IC50/IC90 values. IC/IC values.

In a preferred aspect of the invention the compound is administered within 96 hours from the time

of symptom onset, preferably within 48 hours from the time of symptom onset. For example, in a

patient as defined under item (i), above (i.e. a patient that is <1 year) the compound may be

administered within 96 hours from the time of symptom onset. In a patient as defined under item

(ii), above, (i.e. a patient that is 1 to <12 years) the compound may be administered within 48

hours from the time of symptom onset. The symptom onset may be the time point of the onset of at

least one systemic symptom and/or at least one respiratory symptom. Said at least one systemic

symptom may be at least one symptom selected from headache, feverishness, chills, muscular

pain, joint pain, and fatigue. Said symptom(s) may be noticed by the patient, parent or caregiver.

Said at least one respiratory symptom may be at least one symptom selected from coughing, sore sore

throat, and nasal congestion. Preferably, the time point of the onset of influenza symptoms is

confirmed by verifying that within 24 hours from the above time point, that the body temperature

reaches 38°C to 40°C or more.

After administration of the compound to be used in the present invention the plasma concentration

of the compound of formula (II) may lead to similar exposures to the ones achieved in non-Asian

adult patient population at the dose of 40 mg in the T0831 study, i.e. AUC=3371 ng.h/mL, Cmax= C=

56.9 ng/ml and C24=33.1 ng/mL. C=33.1 ng/mL. Administration Administration ofof the the compound compound toto bebe used used inin the the present present

invention preferably leads to an accelerated recovery from the influenza virus infection of the

treated patient as compared to an untreated patient to whom the compound has not been

administered. Or, in other words, preferably the treated patient to whom the compound to be used

in the present invention has been administered has a reduced time to recovery as compared to an

untreated patient to whom the compound has not been administered. Herein, the term "untreated

patient" means that said patient did not receive the compound to be used in the present invention,

i.e. did not receive the compound having the formula (I) or (II) or a pharmaceutically acceptable

salt thereof. However, said "untreated patient" may or may not have received another medicament,

e.g. another antiviral drug. For example, in the present invention the untreated patient may have

been administered with oseltamivir. In one example a patient which receives the compound to be

used in the present invention is 1 year or older but younger than 12 years and the untreated patient

has been administered with oseltamivir. The treatment regimen of oseltamivir is commonly known

in the art. For example, oseltamivir may be administered twice daily for 5 days. Appropriate doses

for oseltamivir are based on body weight and commonly known in the art. It is preferred in the

present invention that the compound to be used herein leads to a better therapeutic effect as

compared to oseltamivir administration.

WO wo 2021/028024 PCT/EP2019/071699 PCT/EP2019/071699 19

The treated patient to whom the compound has been administered preferably has a decreased

virological activity as compared to an untreated patient to whom the compound has not been

administered. For example, it is preferred that the change from baseline in the virus titer is at least

-4.20 log10 (TCID50/mL), log (TCID/mL), and/or and/or thatthat the the change change fromfrom baseline baseline in the in the amount amount of viral of viral RNA RNA is least is at at least

-1.75 log10 (virus log (virus particles/mL) particles/mL) onon Day Day 2 2 (i.e. (i.e. two two days days after after administration administration ofof the the compound compound toto bebe

used herein, which is administered on Day 0).

For example, the virological activity may be decreased in the treated patient within 86 hours after

administration of the compound to be used in the present invention, and may remain decreased for

at least 21.5 hours. Measurement of the virological activity is commonly known in the arg. For

example, the virological activity may be measured by:

(a) determination of the time to cessation of viral shedding;

(b) determination determination of of the the influenza influenza virus virus titer; titer; and/or and/or

(c) determination the amount of virus RNA.

In this regard, the duration of influenza virus shedding may be measured as time to shedding

cassation following symptom onset. The amount of virus RNA may be measured by using reverse

transcriptase-polymerase chain reaction (RT-PCR). The virus titer may be measured in the

following manner.

(1) )MDCK-SIAT1 cells seeded MDCK-SIAT1 cells seeded in in aa flat-bottom flat-bottom 96-well 96-well microplate microplate are are cultured cultured in in aa 5% 5% CO CO2

incubator at 37+1°C 37±1°C for 1 day.

(2)A standard strain (e.g. influenza virus AH3N2, A/Victoria/361/2011, storage condition: -80°C,

origin: National Institute of Infectious Diseases), a sample (collected from a patient and stored in

an ultra-low-temperature freezer), and a medium for cell control are diluted 101 to 107 folds by

a 10-fold serial dilution method.

(3) After cells present in a sheet form are confirmed under an inverted microscope, the medium is

removed, and a new medium is added at 100 uL/well. µL/well.

(4) The medium is removed.

(5) Each of the samples (101 to 107) prepared in (2) above is inoculated at 100 uL/well, µL/well, using 4

wells per sample.

6)Centrifugal (6) Centrifugal adsorption adsorption is is performed performed at at room room temperature temperature at at 1000 1000 rpm rpm for for 30 30 minutes. minutes.

(7) After centrifugation, the medium is removed, and cells are washed once with a new medium.

(8)A newmedium (8) new mediumis isadded addedat at100 100µL/well. uL/well.

(9) Incubation is performed in a 5% CO2 incubator at CO incubator at 33±1°C 33+1°C for for 33 days. days.

(10)After incubation, the CytoPathic Effect (CPE) is evaluated under an inverted microscope.

It is preferred that the compound to be used in the present invention reduces the time to alleviation

of influenza signs and symptoms (TASS) by at least 6 hours, preferably by at least about 12 hours

WO wo 2021/028024 PCT/EP2019/071699 PCT/EP2019/071699

20 (e.g. by about 24 hours or more) as compared to an untreated patient to whom the compound has

not been administered. More specifically, the compound preferably reduces TASS by at least 6

hours, preferably by at least about 12 hours (e.g. by about 24 hours or more) relative to their

respective placebos (or relative to an untreated patient). In line with this, it is preferred that the time

from diagnosis of the influenza virus infection until recovery is decreased in the treated patient to

whom the compound has been administered as compared to an untreated patient to whom the

compound has not been administered. In this regard the patient may be classified as being

recovered when at least one of the following recovery criteria is met and remains met for at least

21.5 hours:

(a) return to afebrile state (tympanic temperature 37.2 37.2°C); °C);

(b)a score of 0 (no problem) or 1 (minor problem) for cough and nasal symptoms as specified in

items 14 and 15 of the Canadian Acute Respiratory Illness and Flu Scale (CARIFS), preferably

a score of 0 (no problem) or 1 (minor problem) for all 18 symptoms specified in the (CARIFS);

(c) cessation of viral shedding; and/or

(d)return returnto tonormal normalhealth healthand andactivity. activity.

The Canadian Acute Respiratory Illness and Flu Scale (CARIFS) can be used to identify a

treatment benefit of the compound to be used in the present invention (e.g. baloxavir marboxil).

The CARIFS is commonly known in the art and shown in Figure 9. The CARIFS is a reliable

questionnaire which is composed of 18 questions, each with a 4-point Likert response. The

CARIFS questionnaire can be completed by the patient, parent, caregiver and/or physician and

covers three domains: symptoms (e.g., cough), function (e.g., play), and parental impact (e.g.,

clinginess). The CARIFS is calculated as the sum of the items and measures duration of illness.

The return to normal health and activity may be achieved if the patient is able to return to day care

or school, and/or to resume his or her normal daily activity in the same way as performed prior to

developing the influenza virus infection.

Administration of the compound to be used in the present invention may prevent the occurrence of

an influenza-related complication. Said influenza-related complication may be at least one of the

complications selected from the group consisting of radiologically confirmed pneumonia, bronchitis,

sinusitis, otitis media, encephalitis/encephalopathy, febrile seizures, encephalitis/encephalopathy febrile seizures, and and myositis. myositis. Generally Generally

subsequent or partially overlapping with the initial acute viral illness, the most common

complications of influenza in children are otitis media, pneumonia (primary influenza virus and

secondary bacterial pneumonia), respiratory failure, and seizures (Mistry, Pediatrics 134.3 (2014):

e684-e690). These most common complications are preferably prevented in the patient who is

treated with the compound to be used in the present invention. It is further envisaged that death of

the patient caused by the influenza virus infection is prevented by the administration of the

WO wo 2021/028024 PCT/EP2019/071699 PCT/EP2019/071699 21 compound. Usually, influenza infected persons do not die from the influenza infection per se but

because of the development of a bacterial superinfection. Herein the term "death (of the patient)

caused by the influenza virus infection" also includes death which is caused by a bacterial

superinfection which had developed in an influenza infected person.

In the context of the present invention it is further envisaged that the requirement of antibiotics is

prevented by the administration of the compound. Usually, a bacterial superinfection leads to the

requirement of antibiotics. Thus, in accordance with the present invention, a bacterial

superinfection may be prevented in the treated patient. Another condition which usually leads to a

requirement of antibiotics is an asthma attack. Administration of the compound to be used in the

present invention may also prevent hospitalization of the treated patient.

As detailed herein above and below, the compound to be used in the present invention may have

the formula (I), (II) or may be a pharmaceutically acceptable salt of the compound of formula (I) or

(II). In a preferred aspect of the present invention the compound has the formula (I). The

compound to be used in accordance with the present invention may be combined with other anti-

influenza drugs. Four antiviral drugs are currently approved in the EU for the prevention and

treatment of influenza: the M2 ion-channel inhibitor amantadine and the NAIs oseltamivir

phosphate, zanamivir and peramivir. A second M2 inhibitor, rimantadine, holds marketing

authorisations in the Czech Republic, France and Poland but is not marketed in these countries.

Therefore, the compound to be used in the present invention may be administered as co-therapy

with amantadine, oseltamivir phosphate, zanamivir, peramivir, and/or rimantadine. Neuraminidase

inhibitors (NAIs) are the mainstay of treatment for influenza infections. Therefore, if the compound

to be used in the present invention is administered as co-therapy, then it is preferably combined

with oseltamivir phosphate or zanamivir. Both oseltamivir phosphate and zanamivir are

administered twice daily for 5 days.

The patient to be treated in the present invention is preferably healthy beside the influenza virus

infection. It is preferred that the patient is not treated with any medicament beside the compound to

be used in the present invention. For example, it is preferred that the patient is not treated with an

investigational therapy, a systemic antiviral drug (e.g. peramivir, laninamivir, oseltamivir, zanamivir,

rimantadine, rimantadine, umifenovir umifenovir or or amantadine), amantadine), immunosuppressants, immunosuppressants, corticosteroids, corticosteroids, antifungal antifungal drugs, drugs, or or

a drug which is administered to the eyes, nose or ears, or by inhalation. However, if influenza

symptoms, such as fever and headache, are so severe (e.g. in the opinion of the patient and/or

caregiver) that the patient needs pain treatment, then the compound to be used in context of the

present invention may be combined with acetaminophen (i.e. paracetamol). Acetaminophen may

be administered at a dose appropriate to the age and body weight of the pediatric patient.

WO wo 2021/028024 PCT/EP2019/071699

22

In one aspect of the present invention the patient does not meet one of the following exclusion

criteria:

(i) requires hospitalization (e.g. because of severe symptoms of influenza, complications of

influenza or significant comorbidities);

(ii) has concurrent infections requiring systemic antiviral therapy;

(iii) is a preterm neonate (born at < 37 weeks gestation) and/or weighing < 2.5 kg at screening;

(iv) is obtaining concomitant treatment with steroids or other immunosuppressant therapy;

(v) has an HIV infection or another immunosuppressive disorder;

(vi) has an uncontrolled renal, vascular, neurologic, or metabolic disease (e.g., diabetes, thyroid

disorders, adrenal disease), hepatitis, cirrhosis, or pulmonary disease or patients with known

chronic renal failure;

(vii) has active cancer at any site;

(viii) has a history of organ transplantation;

(ix) has a known allergy to the compound of the invention or to acetaminophen (also known as

paracetamol); and

(x) is a female who has commenced menarche (i.e., child-bearing potential).

The meaning of the term "influenza virus infection" or variations thereof is commonly known in the

art and refers to a disease which is caused by the influenza virus. More specifically, an influenza

virus infection is an acute respiratory infectious disease caused by a virus of the orthomyxovirus

family. Two forms are known to principally infect humans and to cause disease in humans, the

influenza A virus and the influenza B virus. The influenza viruses have a segmented, negative-

sense, single-stranded, lipid encapsulated ribonucleic acid (RNA) genome; they range between 80

and 100 nm in size. Subtypes are defined according to haemagglutinin (HA) and neuraminidase

(NA) glycoproteins present in the viral lipid coat. Influenza viruses enter the respiratory epithelial

cell by attachment of the viral HA to sialic acid-containing receptors on the cell membrane, followed

by internalisation of the virus into an acidic endosome. In the acidic environment of the endosome,

the HA undergoes a conformational change that liberates a fusion peptide and results in fusion of

the viral envelope with the endosomal membrane. At the same time the matrix-2 (M2) protein acts

as an ion channel allowing hydrogen ions to enter the virion from the endosome. This allows the

viral gene segments to leave the virion and enter the cytoplasm, a process known as uncoating.

Viral gene segments are transported to the nucleus where the viral polymerase complex,

composed of the proteins polymerase basic protein 1 (PB1), polymerase basic protein 2 (PB2),

and polymerase acidic protein (PA), directs the synthesis of the plus-sense messenger RNA

(mRNA) as well as, via a plus-sense full length complementary RNA, synthesis of negative-sense

full length copies that will serve as progeny genomic RNA. The polymerase proteins also play a

role in disruption of host cell protein synthesis. Assembly of progeny virions occurs at the plasma membrane, and the viral NA protein plays a role in release of virus from the cell surface by cleavage of surface sialic acid.

The "compound" to be used in the present invention is a compound which has one of the following

formulae I and II:

(I) (II)

O MeO O OH O OH 0 0 0 o N N N., N 0 N o 0 N N 11 -

F F S S F F

or its pharmaceutically acceptable salt (i.e. of the compound having a formula of (I) or (II)). The

compound to be used in the present invention is also referred to herein as "compound", "compound

for use", "compound to be used (herein/in the present invention)" or "compound of the present

invention".

The compound to be used in the present invention acts as a selective cap-dependent endonuclease (CEN) inhibitor, inhibiting the 'cap-snatching' function of the PA subunit of the

influenza polymerase, which is used to cleave 5' cap structures from host cell mRNAs, which are

used as primers for viral mRNA transcription. By inhibiting this essential function, the compound as

used herein suppresses the replication of influenza viruses.

The compound to be used in the present invention has a broad spectrum of activity against

seasonal (e.g. A/H1N1, A/H3N2, and B) and highly pathogenic avian (e.g. A/H5N1, A/H7N9)

influenza viruses, with more potent antiviral activity (lower half maximal inhibitory concentration

[IC50]) compared

[IC]) compared with with other other common common anti-influenza anti-influenza drugs drugs such such asas oseltamivir, oseltamivir, zanamivir, zanamivir, oror

peramivir. The compound's ability to be efficacious as a single dose administration simplifies

treatment and improves patient compliance compared to neuraminidase inhibitors (NAls). (NAIs).

Preferably, the compound has the formula of (I) or (II), most preferably of (I). The compound of

formula (I) can also be displayed as follows:

PCT/EP2019/071699

24 F F S F

H H N N

N o o o

o o

o O Baloxavir marboxil (BXM)

This compound (i.e. the compound of formula (I)) has a molecular formula of C27H23F2N3O7S. CHFNOS. This This

compound is a pro-drug which is known as baloxavir marboxil. Baloxavir marboxil is known in the

art and described, e.g., in Noshi, Antiviral research 160 (2018): 109-117.

Baloxavir marboxil (i.e. the compound of formula (I)) is an anti-influenza virus drug with a novel

mechanism of action. It was discovered and is being developed by Shionogi & Co., Ltd. and F.

Hoffman-La Roche, Ltd. Baloxavir marboxil (S-033188) is a pro-drug and is converted to an active

form baloxavir (S-033447) through metabolism (hydrolysis). The active form is shown herein as

formula (II). The active form baloxavir (S-033447) selectively inhibits cap-dependent endonuclease

(CEN) activity necessary for replication of influenza viruses (Omoto, Sci Rep. 2018; 8(1):9633). A

broad spectrum of activity against seasonal influenza viruses and on alleviating effects of influenza

symptoms were shown in nonclinical efficacy studies and clinical studies in patients with influenza,

including the phase 2 proof of concept and dose-finding study, the phase 3 double-blind study in

otherwise healthy patients (Portsmouth S, Kawaguchi K, Arai M, Tsuchiya K, Uehara T. Cap-

dependent endonuclease inhibitor baloxavir marboxil (S-033188) for the treatment of influenza:

results from a phase 3, randomized, double-blind, placebo- and active-controlled study in

otherwise healthy adolescents and adults with seasonal influenza. Abstract LB-2. Oral presentation

at ID Week 2017, October 4-8 2017, San Diego, CA, USA.), and the Phase 3 open-label study in

otherwise healthy pediatric patients.

The compound as shown in formula (II) is the active form of baloxavir marboxil (i.e. of the pro-drug

of formula (I)). The compound of formula (I) can also be displayed as follows:

F S F

H H - N o O N

N O o O OH

Baloxavir acid (BXA)

The compound of formula (II) is also known as baloxavir or baloxavir acid. Baloxavir acid is known

in the art and described, e.g., in Noshi, Antiviral research 160 (2018): 109-117.

The pharmaceutically acceptable salts of the compounds used in the present invention include, for

example, salts with alkaline metal (e.g., lithium, sodium, potassium or the like), alkaline earth metal

(e.g., calcium, barium or the like), magnesium, transition metal (e.g., zinc, iron or the like),

ammonia, organic bases (e.g., trimethylamine, triethylamine, dicyclohexylamine, ethanolamine,

diethanolamine, diethanolamine, triethanolamine, triethanolamine, meglumine, meglumine, ethylenediamine, ethylenediamine, pyridine, pyridine, picoline, picoline, quinoline quinoline or or the the

like) like) or or amino amino acids, acids, or or salts salts with with inorganic inorganic acids acids (e.g., (e.g., hydrochloric hydrochloric acid, acid, sulfuric sulfuric acid, acid, nitric nitric acid, acid,

carbonic acid, hydrobromic acid, phosphoric acid, hydroiodic acid or the like) or organic acids (e.g.,

formic acid, acetic acid, propionic acid, trifluoroacetic acid, citric acid, lactic acid, tartaric acid,

oxalic acid, maleic acid, fumaric acid, mandelic acid, glutaric acid, malic acid, benzoic acid,

phthalic acid, ascorbic acid, benzenesulfonic acid, p-toluenesulfonic acid, methanesulfonic acid,

ethanesulfonic acid or the like). Especially, salts with sodium, potassium, calcium, magnesium,

iron and the like are included. These salts can be formed by the usual methods.

The production of the compound of the present invention is well known in the art. For example, the

compound of the present invention can be prepared with the methods described in the patent

application PCT/JP2016/063139, which is published as WO 2016/175224A1.

As mentioned above, in accordance with the present invention, it is preferred that the influenza

virus strain does not comprise a PA protein having a sequence which has at least 80%, preferably

at least 90%, more preferably at least 95%, at least 96%, at least 97%, at least 98%, or at least

99% sequence identity to the sequence of SEQ ID NO:1 and comprising a substitution (e.g. an I to

T substitution) at the position corresponding to position 138 I38 of SEQ ID NO:1. In particular, FASTA

sequences of two sequences of viral PA proteins can be generated and aligned in order to

evaluate the degree of identity between the two viral PA proteins. To determine the percent identity of two sequences, the sequences are aligned for optimal comparison purposes (e.g., gaps can be introduced in one or both of a first and a second amino acid sequence for optimal alignment and non-homologous sequences can be disregarded for comparison purposes). The percent identity between the two sequences is a function of the number of identical positions shared by the sequences, taking into account the number of gaps, and the length of each gap, which need to be introduced for optimal alignment of the two sequences. Percent identity between two polypeptides/amino acid sequences is determined in various ways which are known by the skilled person, for instance, using publicly available computer software such as Smith Waterman

Alignment (Smith, T. F. and M. S. Waterman (1981) J Mol Biol 147:195-7); "BestFit" (Smith and

Waterman, Advances in Applied Mathematics, 482 489 (1981)) as incorporated into GeneMatcher

PlusTM, Schwarz Plus Schwarz andand Dayhof Dayhof (1979), (1979), Atlas Atlas of of Protein Protein Sequence Sequence andand Structure, Structure, Dayhof, Dayhof, M.O., M.O., Ed,Ed,

pp 353-358; BLAST program (Basic Local Alignment Search Tool; (Altschul, S. F., W. Gish, et al.

(1990) J Mol Biol 215: 403-10), BLAST-2, BLAST-P, BLAST-N, BLAST-X, WU-BLAST- 2, ALIGN,

ALIGN-2, CLUSTAL, or Megalign (DNASTAR) software. In addition, those skilled in the art can

determine appropriate parameters for measuring alignment, including any algorithms needed to

achieve maximal alignment over the length of the sequences being compared. Preferably, the viral

PA protein sequences are compared over their entire lengths. For purposes of the present

invention, the comparison of sequences and determination of percent identity between two

sequences can be accomplished using a Blossum 62 scoring matrix (with a gap penalty of 12, a

gap extend penalty of 4, and a frameshift gap penalty of 5).

As described above, the present invention provides means and methods for treating an influenza

virus infection of patients that are younger than 12 years, in particular by providing an optimized

dosage for these pediatric patients. In line with this, the invention also relates to the following

aspects. All explanations, definitions and preferred aspects which are explained above and below

also relate, mutatis mutandis, to the inventive aspects described below.

The invention also relates to a compound for use in treating an influenza virus infection, wherein

the compound has one of the formulae (I) and (II) or its pharmaceutically acceptable salt, and

wherein the following dosage is used:

(i) in a patient that is younger than 1 year:

(a) if (a) thethepatient patient is is younger younger than than4 4weeks, then weeks, the the then effective amountamount effective is 0.8-1.2 mg/kg is 0.8-1.2 mg/kg

body weight, preferably about 1 mg/kg body weight;

(b) the (b)if patient the is is patient 4 weeks or or 4 weeks older but older younger but than younger 3 months, than then 3 months, the then effective the effective

amount is 0.8-1.2 mg/kg body weight, preferably about 1 mg/kg body weight;

(c) (c) if if the the patient patient is is 33 months months or or older older but but younger younger than than 12 12 months, months, then then the the effective effective

amount is 1.8-2.2 mg/kg body weight, preferably about 2 mg/kg body weight;

(ii) in a patient that is 1 year or older but younger than 12 years:

(a)if the (a) the patient patient has has a a body body weight weight ofof less less than than 2020 kg, kg, then then the the effective effective amount amount isis 1.8- 1.8-

2.2 mg/kg body weight, preferably about 2 mg/kg body weight; or

(b) if the (b)if the patient patient has has aa body body weight weight of of 20 20 kg kg or or more, more, then then the the effective effective amount amount is is 35-45 35-45

mg, preferably about 40 mg.

The invention further relates to a pharmaceutical composition for use in treating an influenza virus

infection, wherein the pharmaceutical composition comprises the compound having one of the

formulae (I) and (II) or its pharmaceutically acceptable salt, and optionally comprising a

pharmaceutically acceptable carrier, wherein the following dosage is used:

(i) in a patient that is younger than 1 year:

(a)i the patient (a) the patient is is younger younger than than 44 weeks, weeks, then then the the effective effective amount amount is is 0.8-1.2 0.8-1.2 mg/kg mg/kg

body weight, preferably about 1 mg/kg body weight;

(b)i (b)itthe thepatient patientis is4 4weeks weeksor orolder olderbut butyounger youngerthan than3 3months, months,then thenthe theeffective effective

amount is 0.8-1.2 mg/kg body weight, preferably about 1 mg/kg body weight;

(c) (c) if if the the patient patient is is 33 months months or or older older but but younger younger than than 12 12 months, months, then then the the effective effective

amount is 1.8-2.2 mg/kg body weight, preferably about 2 mg/kg body weight;

(ii) in a patient that is 1 year or older but younger than 12 years:

(a)i the patient has a body weight of less than 20 kg, then the effective amount is 1.8-

2.2 mg/kg body weight, preferably about 2 mg/kg body weight; or

(b) (b)iif the the patient patient has has a a body body weight weight ofof 2020 kgkg oror more, more, then then the the effective effective amount amount isis 35-45 35-45

mg, preferably about 40 mg.

Also encompassed by the present invention is a method for treating influenza, comprising: reading

a dosage instruction on a package insert or in a package for a pharmaceutical formulation

comprising a compound having one of the formulae (I) and (II)) or being a pharmaceutically salt

thereof; and administering an effective amount of the compound to an influenza-infected patient,

and wherein the following dosage is used:

(i) in a patient that is younger than 1 year:

(a) the patient is younger than 4 weeks, then the effective amount is 0.8-1.2 mg/kg

body weight, preferably about 1 mg/kg body weight;

(b)i thepatient (b) the patientis is44weeks weeksor orolder olderbut butyounger youngerthan than33months, months,then thenthe theeffective effective

amount is 0.8-1.2 mg/kg body weight, preferably about 1 mg/kg body weight;

(c) if the patient is 3 months or older but younger than 12 months, then the effective

amount is 1.8-2.2 mg/kg body weight, preferably about 2 mg/kg body weight;

(ii) in a patient that is 1 year or older but younger than 12 years:

(a)i the patient has a body weight of less than 20 kg, then the effective amount is 1.8-

2.2 mg/kg body weight, preferably about 2 mg/kg body weight; or

(b) if thethe patient patient hashas a body a body weight weight of of 20 20 kg kg or or more, more, then then thethe effective effective amount amount is is 35-45 35-45

mg, preferably about 40 mg.

WO wo 2021/028024 PCT/EP2019/071699 PCT/EP2019/071699

28 The invention also relates the use of a compound which has one of the formulae (I) and (II), or its

pharmaceutically acceptable salt, for the preparation of a medicament for treating an influenza-

infected patient, wherein the following dosage is used:

(i) in a patient that is younger than 1 year:

(a)if the patient (a)i the patient is is younger younger than than 44 weeks, weeks, then then the the effective effective amount amount is is 0.8-1.2 0.8-1.2 mg/kg mg/kg

body weight, preferably about 1 mg/kg body weight;

(b) the patient if the is 4 patient isweeks or older 4 weeks but but or older younger than younger 3 months, than then 3 months, the the then effective effective

amount is 0.8-1.2 mg/kg body weight, preferably about 1 mg/kg body weight;

(c) if the patient is 3 months or older but younger than 12 months, then the effective

amount is 1.8-2.2 mg/kg body weight, preferably about 2 mg/kg body weight;

(ii) in a patient that is 1 year or older but younger than 12 years:

(a)if the patient has a body weight of less than 20 kg, then the effective amount is 1.8-

2.2 mg/kg body weight, preferably about 2 mg/kg body weight; or

(b) if the (b)it the patient patient has has aa body body weight weight of of 20 20 kg kg or or more, more, then then the the effective effective amount amount is is 35-45 35-45

mg, mg, preferably preferablyabout 40 mg. about 40 mg.

Also provided by the present invention is a package comprising a pharmaceutical formulation

comprising a compound which has one of the formulae (I) and (II), or its a pharmaceutically salt,

and further comprising a dosage instruction for administering an effective amount of the compound

to an influenza-infected patient, wherein the following dosage is used:

(i) in a patient that is younger than 1 year:

(a)if the patient (a)i the patient is is younger younger than than 44 weeks, weeks, then then the the effective effective amount amount is is 0.8-1.2 0.8-1.2 mg/kg mg/kg

body weight, preferably about 1 mg/kg body weight;

(b)i (b)ififthe the patient patient is is4 4weeks weeksor or older but but older younger than 3than younger months, then thethen 3 months, effective the effective

amount is 0.8-1.2 mg/kg body weight, preferably about 1 mg/kg body weight;

(c) if the patient is 3 months or older but younger than 12 months, then the effective

amount is 1.8-2.2 mg/kg body weight, preferably about 2 mg/kg body weight;

(ii) in a patient that is 1 year or older but younger than 12 years:

(a)i the patient has a body weight of less than 20 kg, then the effective amount is 1.8-

2.2 mg/kg body weight, preferably about 2 mg/kg body weight; or

(b) if the (b)if the patient patient has has aa body body weight weight of of 20 20 kg kg or or more, more, then then the the effective effective amount amount is is 35-45 35-45

mg, preferably about 40 mg.

As mentioned above, one aspect of the present invention relates to a pharmaceutical composition

comprising a compound which has one of the formulae (I) and (II), or its pharmaceutically

acceptable salt, and optionally comprising a pharmaceutically acceptable carrier. The

pharmaceutical compositions can be formulated with a pharmaceutically acceptable carrier by

known methods. For example, the compositions can be formulated by appropriately combining the

ingredients with a pharmaceutically acceptable carrier or a medium, specifically, sterile water or physiological saline, vegetable oils, emulsifiers, suspending agents, surfactants, stabilizers, 30 Sep 2025 flavoring agents, excipients, vehicles, preservatives, binding agents, and such, by mixing them at a unit dose and form required by generally accepted pharmaceutical implementations. Specific examples of the carriers include light anhydrous silicic acid, lactose, crystalline cellulose, mannitol, starch, carmellose calcium, carmellose sodium, hydroxypropyl cellulose, hydroxypropyl methylcellulose, polyvinylacetal diethylaminoacetate, polyvinylpyrrolidone, gelatin, medium-chain 22051576_1 (GHMatters) P118017.AU triglyceride, polyoxyethylene hardened castor oil 60, saccharose, carboxymethyl cellulose, corn starch, inorganic salt, and such. The content of the active ingredient in such a formulation is 2019461218 adjusted so that an appropriate dose within the required range can be obtained.

The pharmaceutical composition may optionally comprise one or more pharmaceutically acceptable excipients, such as carriers, diluents, fillers, disintegrants, lubricating agents, binders, colorants, pigments, stabilizers, preservatives, antioxidants, or solubility enhancers. Also, the pharmaceutical compositions may comprise one or more solubility enhancers, such as, e.g., poly(ethylene glycol), including poly(ethylene glycol) having a molecular weight in the range of about 200 to about 5,000 Da, ethylene glycol, propylene glycol, non-ionic surfactants, tyloxapol, polysorbate 80, macrogol-15-hydroxystearate, phospholipids, lecithin, dimyristoyl phosphatidylcholine, dipalmitoyl phosphatidylcholine, distearoyl phosphatidylcholine, cyclodextrins, hydroxyethyl-β-cyclodextrin, hydroxypropyl-β-cyclodextrin, hydroxyethyl-γ-cyclodextrin, hydroxypropyl-γ-cyclodextrin, dihydroxypropyl-β-cyclodextrin, glucosyl-α-cyclodextrin, glucosyl-β- cyclodextrin, diglucosyl-β-cyclodextrin, maltosyl-α-cyclodextrin, maltosyl-β-cyclodextrin, maltosyl-γ- cyclodextrin, maltotriosyl-β-cyclodextrin, maltotriosyl-γ-cyclodextrin, dimaltosyl-β-cyclodextrin, methyl-β-cyclodextrin, carboxyalkyl thioethers, hydroxypropyl methylcellulose, hydroxypropylcellulose, polyvinylpyrrolidone, vinyl acetate copolymers, vinyl pyrrolidone, sodium lauryl sulfate, dioctyl sodium sulfosuccinate, or any combination thereof.

The pharmaceutical compositions are not limited to the means and methods described herein. The skilled person can use his/her knowledge available in the art in order to construct a suitable composition. Specifically, the pharmaceutical compositions can be formulated by techniques known to the person skilled in the art such as the techniques published in Remington’s Pharmaceutical Sciences, 20th Edition.

In the claims which follow and in the description of the invention, except where the context requires otherwise due to express language or necessary implication, the word “comprise” or variations such as “comprises” or “comprising” is used in an inclusive sense, i.e. to specify the presence of the stated features but not to preclude the presence or addition of further features in various embodiments of the invention.

22051576_1 (GHMatters) P118017.AU

29a 30 Sep 2025

The content of all documents cited herein above and below is incorporated by reference in its entirety.

The present invention is further described by reference to the following non-limiting figures and examples. 22051576_1 (GHMatters) P118017.AU

2019461218

22051576_1 (GHMatters) P118017.AU

The Figures show:

Figure 1: Simulated total drug exposure for three different dosing regimens in pediatrics (Non-

Asian, Age 1-12 year olds). Bottom and top of the boxplot represent 25th and 75th percentile;

middle line in the box represents 50th percentile; lower and upper whisker represent 10th and 90th

percentile. Note: for ease of simulations of regimen 2, the weight at which bodyweight-based

dosing converts to flat dosing was 26.6 kg.

Figure 2: Simulated peak drug exposure for three different dosing regimens in pediatrics (Non-

Asian, Age 1-12 year olds). Bottom and top of the boxplot represent 25th and 75th percentile;

middle line in the box represents 50th percentile; lower and upper whisker represent 10th and 90th

percentile. Note: for ease of simulations of regimen 2, the weight at which bodyweight-based

dosing converts to flat dosing was 26.6 kg.

Figure 3: Simulated drug exposure at 24 hours after dosing for three different dosing regimens in

pediatrics (Non-Asian, Age: 1-12 year olds). Bottom and top of the boxplot represent 25th and 75th

percentile; middle line in the box represents 50th percentile; lower and upper whisker represent 10th

and 90th percentile. Note: for lease of simulations ease of simulations of of regimen regimen 2, 2, the the weight weight at at which which bodyweight- bodyweight-

based dosing converts to flat dosing was 26.6 kg.

Figure 4: Simulated drug exposure at 72 hours after dosing for three different dosing regimens in

pediatrics (Non-Asian, Age: 1-12 year olds). Bottom and top of the boxplot represent 25th and 75th

percentile; middle line in the box represents 50th percentile; lower and upper whisker represent 10th

and 90th percentile. Note: for ease of simulations of regimen 2, the weight at which bodyweight-

based dosing converts to flat dosing was 26.6 kg.

Figure 5: Simulated total drug exposure for three different dosing regimens in pediatrics (Non-

Asian, Age: < 1 year old). Bottom and top of the boxplot represent 25th and 75th percentile; middle

line in the box represents 50th percentile; lower and upper whisker represent 10th and 90th

percentile. Grey box with rounded edges indicates nearly identical match with adult exposures in

this model.

Figure 6: Simulated peak drug exposure for three different dosing regimens in pediatrics (Non-

Asian, Age: < 1 year olds). Bottom and top of the boxplot represent 25th and 75th percentile; middle

line in the box represents 50th percentile; lower and upper whisker represent 10th and 90th

percentile.

WO wo 2021/028024 PCT/EP2019/071699 31 Figure 7: Simulated drug exposure at 24 hours after dosing for three different dosing regimens in

pediatrics pediatrics (Non-Asian, (Non-Asian, Age: Age: <1 < 1year yearolds). olds).Bottom Bottomand andtop topofofthe theboxplot boxplotrepresent represent25th 25thand and75th 75th

percentile; middle line in the box represents 50th percentile; lower and upper whisker represent 10th

and 90th percentile.

Figure 8: Simulated drug exposure at 72 hours after dosing for three different dosing regimens in

pediatrics (Non-Asian, pediatrics (Non-Asian, Age: Age: < 1 < year year olds). olds). Bottom Bottom andoftop and top theof the boxplot boxplot represent represent 25th and 75th 25th and 75th

percentile; middle line in the box represents 50th percentile; lower and upper whisker represent 10th

and 90th percentile.

Figure 9: Canadian Acute Respiratory Illness and Flu Scale (CARIFS) Questionnaire.

Figure 10: The powder X-ray diffraction pattern of the crystal of compound I of Example 6.

The Examples illustrate the invention.

Example 1: Materials and Methods of the Simulation of pediatric doses

1. Population Pharmacokinetic (PK) Analysis

Population PK analysis were conducted using Japanese pediatric patient study information.

1.1 Background Data Following background data available for subjects were summarized and were used as the

candidate of covariates: age (years and weeks), body weight, body mass index (BMI), aspartate

aminotransferase (AST), alanine aminotransferase (ALT), total bilirubin (Tbil), estimated glomerular

filtration rate (eGFR), and creatinine clearance (CLcr) at baseline as continuous data, and gender

(male, female), race ("Asian", "Non-Asian", wherein the "Non-Asian" group reflects, e.g., white such

as Caucasian patients), health status (otherwise healthy patients with influenza, or patients without

influenza) and food conditions (dosing 4 4hours hoursbefore beforeand and4 hours after 4 hours food after intake food [fasted], intake [fasted], dosing within 2 to 4 hours before or 2 to 4 hours after food intake [intermediate], or dosing < 2

hours before or < 2 hours after food intake [fed]) as categorical data. Background data at baseline

were obtained from observations prior to or on the first day of dosing or at screening if this value

was not available. The eGFR was calculated by Schwartz formula (Schwartz, Pediatric Clinics of

North America. 1987; 34: 571-90). CLcr for pediatrics was calculated from eGFR and body surface

area (BSA). The BSA was calculated using the following equation reported by Mostellar (Mosteller,

N Eng J Med. 1987;317:1098).

BSA (m ² = [height (cm) x body weight (kg)/3600]1/2 (m²) (kg)/3600]¹²

The following equations were used to calculate eGFR and CLcr.

Parameter Age Equation

2 to 11 years eGFR == 0.55 eGFR 0.55X [height

[height (cm)]/Scr (cm)]/Scr eGFR (mL/min/1.73 (mL/min/1.73m²) m² Birth to 1 year eGFR = 0.45 x X [height (cm)]/Scr (Full-term infants)

CLer (mL/min) V < 12 years CLer = eGFR X BSA/1.73 CLer=eGFRxBSA/1.73 BSA = body surface area (m ² Scr (m²; Ser = serum creatinine (mg/dL)

1.2 Base Model

A 2-compartment model with first-order absorption and lag time was initially tested for describing

plasma concentration of baloxavir (S-033447), because it is the same structural model that was

previously selected to describe the data in pediatric patients (Ishibashi T. Population

Pharmacokinetics of S-033188 (Pediatric Patient). Study Report (Final, Study No.: S-033188-CB-

273-N). Shionogi & Co., Ltd.; 2017). The 2-compartment model includes the following parameters:

apparent total clearance (CL/F), apparent volume of central and peripheral compartments (Vc/F

and Vp/F), apparent inter-compartmental clearance (Q/F), first-order rate of absorption (Ka), and

absorption lag time (ALAG). The difference of systemic exposure among formulations was

incorporated in the model as the difference of relative bioavailability (F). F is 1 for to-be-marketed

20-mg tablet and 0.88 for to-be-marketed 10-mg tablet (A Phase 1 Study to Evaluate the

Bioequivalence of S-033188 10-mg and 20-mg Tablets and Effect of Food on the Pharmacokinetics in Healthy Adults. Clinical Study Report (Study No. 1622T081F). Shionogi & Co.,

Ltd.; 2017). F was set to 1 for 2% granule in this study because 2% granule and 20-mg tablet is

bioequivalent (Study No. 1703T081G) (A Phase 1 Study to Evaluate the Bioequivalence of S-

033188 20-mg Tablet and S-033188 Granules 2%. Clinical Study Report (Study No. 1703T081G).

Shionogi & Co., Ltd.; 2018).

Individual model parameters were estimated based on a fixed effect parameter (PKP) and an inter-

individual variability (IIV) for certain PK parameters which are assumed to follow a log-normal

distribution and exponential error model as described in Equation (1):

PKPi PKP == PKP PKP Xx exp exp(NPKP,i) (npkp,i) (1) (1)

where PKP represents the i-th individual value of PK parameters, PKP represents the typical value

of population PK parameters, and nPKP,i denotes , denotes the difference the difference between between the i-th the i-th individual individual and and

typical typicalPKPKparameter. The The parameter. nPKP is aa random randomvariable of of variable the the IIV IIV parameters and normally parameters distributed and normally distributed WPKP² with a mean of 0 and a variance of WPKP2.

PCT/EP2019/071699

33

After model building, the covariance between pairs of random IIV parameters were examined

graphically by plotting nPKP, in different , in different PK parameters PK parameters and and covariance covariance might might be added be added as as

appropriate to account for observed correlations. Decisions regarding the inclusion of covariance of

IIV were based on the numerical stability of the resulting model or on the goodness-of-fit (GOF)

plots as described in Section 1.5.

Shrinkage Shrinkageinineach NPKP(sh_npkp) each (sh_nPKP) was was computed computedininNONMEM. NONMEM.

The additive error model, the proportional error model and/or the combination error model (the

additive error + the proportional error model) were tested as an intra-individual (residual) variability.

The additive error model, the proportional error model and the combination error model are given

in the following equations.

Cij = Cij (pred) + ,ij : additive error model (2)

Cij Cij == Cij Cij(pred) (pred) + +E1.ij) x (1 ,i) : proportional error model (3)

Cij = Cij (pred) x (1 + ,ij) + ,ij : combination error model (4) Cij = + E2,ij where Cii Cij represents the observed j-th concentration in the i-th individual, Cij (pred) represents the

j-th concentration predicted from the i-th individual PK parameters and E (E1,ij, (E1,ij, ,ij) E2,IJ) denotes denotes thethe

difference between the j-th observed and predicted concentration in the i-th individual. The E(E1,ij, (E1,ij,

E2,jj) ,ij) isis a a random random variable variable ofof the the intra-individual intra-individual variability variability parameters parameters from from population population mean mean and and

normally distributed with a mean of 0 and a variance of o2 (012, ² (², ²).o22.

Shrinkage in E(sh_) (sh_e) was was computed computed inin NONMEM. NONMEM.

Error model for intra-individual variability was selected by the diagnostic plots described in Section

1.5 and/or the value of objective function value (OBJ) at the statistical significance level of 0.05 (p

< < 0.05) 0.05)based basedonon x2 x² test, thatthat test, is, difference in OBJ in is, difference (AOBJ) OBJ of () less than -3.84 of less for onefor than -3.84 degree one of degree of

freedom represents a statistically significant model improvement.

The structure of the base model with error models was expanded as necessary to best reflect the

characteristic shape of the observations over time. When IIV could not be estimated appropriately,

removal of its IIV term was considered.

1.3 Covariate Model

After building a base model with selection of an error model for intra-individual variability, the

influence of background data was assessed to build a covariate model. Covariate model was

WO wo 2021/028024 PCT/EP2019/071699 PCT/EP2019/071699

34 constructed by means of combination of screening for covariates, forward selection, and stepwise

backward deletion. The significance level of 0.05 based on x2 X² test (p < 0.05) was used for the

screening (AOBJ ( was was lessless thanthan -3.84 -3.84 for for one one degree degree of freedom). of freedom). The The significant significant covariates covariates at at screening were tested in the forward selection at the significance level of 0.05 based on x2 X² test to

construct a full model (AOBJ ( was was lessless thanthan -3.84 -3.84 for for one one degree degree of freedom). of freedom). The The significance significance

level of 0.01 based on x2 x² test was used for the stepwise backward deletion to construct a final

model (AOBJ ( was was moremore thanthan 6.636.63 for for one one degree degree of freedom). of freedom).

As the first covariate assessment, body weight was tested on CL/F and Vc/F because body weight

is considered to be the most significant covariate in pediatrics. Body weight was tested as a

covariate on the other PK parameters (e.g., Vp/F, Q/F etc.).

For body weight, a power model as shown in Equation (5) was used.

PKP PKP == 01xx (COV/median (COV/median of ofCOV)2 COV)² (5)

where where COV COVisisa a values of the values covariate of the and 01, covariate O2 ,areare and the the typical values typical of model values of parameters to be model parameters to be

estimated in equation. The typical allometric exponents of 0.75 on CL/F and Q/F, and 1 on Vc/F

and Vp/F (Holford, Clin. Pharmacokinet. 1996; 30: 329-32; Anderson, Annu Rev Pharmacol

Toxicol. 2008; 48: 303-32) were tested for O2 for for the the effect effect ofof body body weight weight onon clearance clearance and and volume volume

of distribution. Also, exponents of 0.632 on CL/F and Q/F, and 1.03 on Vc/F and Vp/F, which were

estimated in the previous pediatric population PK model for baloxavir (S-033447) (Ishibashi T.

Population Pharmacokinetics of S-033188 (Pediatric Patient). Study Report (Final, Study No.: S-

033188-CB-273-N). Shionogi & Co., Ltd.; 2017; published (Koshimichi, Journal of Pharmaceutical

Sciences (2019) 1-6, https://doi.org/10.1016/j.xphs.2019.04.010), were tested for O2 for for the the effect effect

of body weight on clearance and volume of distribution.

In addition to body weight, age (weeks), BMI, gender, AST, ALT, Tbil, eGFR, CLcr, and health

status were tested as a covariate on CL/F; age (weeks), BMI, gender, and health status were

tested as a covariate on Vc/F; age (weeks), gender, health status and food conditions were tested

as a covariate on Ka; and food conditions was tested as a covariate on F. Background data was

tested as a covariate on the other PK parameters (e.g., Vp/F, Q/F etc.).

Prior to building covariate models, plots for relationships between covariates and PK parameters

were generated for visual inspection of covariates based on the base model.

For continuous covariates, a power model as shown in Equation (6) was used.

WO wo 2021/028024 PCT/EP2019/071699

35 PKP PKP == 01xx (COV/median (COV/median of ofCOV)2 COV)² (6)

where where COV COVisisa a values of the values covariate of the and 01, covariate O2 ,areare and the the typical values typical of model values of parameters to be model parameters to be

estimated in equation.

For binary and categorical covariates, a multiplicative model as shown in Equation (7) was used.

PKP = CAT=0 x (OCAT_i)AT¹ (7)

where CAT_i is a series of indicator variables with a value of either 0 or 1 assigned (CAT_1,

CAT_2, CAT_n representing the in levels of n levels of CAT; CAT; e.g., e.g., CAT_1 CAT_1 == 00 for for male male and and CAT_1 CAT_1 == 11 for for

female), and OCAT=0 is the CAT=0 is the typical typical values values of of model model parameters parameters to to be be estimated estimated when when the the individual individual

categorical covariate index variable is equal to zero and OCAT_ CAT_i is the i-th relative influence of model

parameters to be estimated for categorical covariate index variable when CAT_ CAT_iis isequal equalto toone. one.

After building the final model, for a simulation purpose for younger children aged < 2 years, a

sigmoid hyperbolic model was incorporated in the model (simulation model) to describe the

maturation of CL/F. Maturation factor (MF) is described in Equation (8), and CL/F is multiplied by

MF.

MF = PMAY/(PMAY + (8) (8)

where PMA is postmenstrual age (weeks), TM50 TM isis maturation maturation half-life half-life (weeks), (weeks), and and Y Y isis hill hill

coefficient. PMA was calculated as 40 + age (weeks), assuming that all patients were full-term

delivery. The values of TM50 and TM and Y Y for for baloxavir baloxavir (S-033447) (S-033447) were were estimated estimated from from data. data. Also, Also, the the

values values of ofTM50 TM == 54.2 54.2 weeks weeksand andY Y = 3.92 forfor = 3.92 morphine, whichwhich morphine, is metabolized by uridine is metabolized by uridine diphosphate glucuronosyl transferase (UGT) (Anderson, Paediatr Anaesth. 2011; 21: 222-37),

were tested. The model with the smallest OBJ was selected as the simulation model.

Alternative expressions might be considered for continuous covariates based on trends that were

observed in covariate plots and alternative expressions might be considered for categorical

covariates to facilitate the interpretation of the typical parameter estimates with respect to specific

patient categories.

Highly correlated covariates might be tested in separate models in order to avoid confounding in

the estimation of covariate effects.

WO wo 2021/028024 PCT/EP2019/071699 PCT/EP2019/071699

36 A covariate might be retained in the final model, despite not meeting the criteria above, if there is a

strong pharmacological or physiological rationale for its inclusion.

1.4 Parameter Estimation

The population PK parameters were estimated for the plasma baloxavir (S-033447) concentration

data by NONMEM. The first-order conditional estimation method with interaction (FOCE-I) was

used for the analysis.

1.5 Model Evaluation

The base and final model were evaluated by using the point estimates of PK parameters and their

relative standard error. Also, the following GOF plots with reference lines (identity, zero line, etc.)

were generated for model diagnostics.

Observed concentrations (OBS) versus population predicted concentrations (PRED) in both

linear and log scale with a line of identity and a trend line

OBS versus Bayesian-predicted individual concentrations (IPRED) in both linear and log scale

with a line of identity and a trend line

Conditional weighted residuals (CWRES) or conditional weighted residuals with interaction

(CWRESI) versus PRED with a zero line and a trend line

|Individual weighted residuals (IWRES) (IWRES)|versus versusIPRED IPREDwith witha atrend trendline line

CWRES or CWRESI versus time after reference dose (TARD)

Histogram (optionally QQ plot) of CWRES or CWRESI and IWRES

Plots of empirical Bayesian estimate (EBE) of parameters (only base model) and ETAs versus

the potential covariates

A scatter plot matrix of EBE of ETAs (only final model)

Distributions (e.g., histograms) of EBE of ETAs (only final model)

OBS, IPRED and PRED concentrations versus time overlaid by individual for representative

subjects (secondary any given subjects) (only final model)

The PRED, IPRED, CWRES, CWRESI and IWRES are the reserved terms in NONMEM.

The final model should meet the following criteria:

A "minimization successful" statement is indicated by NONMEM.

A covariance step is completed without warning messages by NONMEM.

The number of significant digits is 3 3for forall allestimated estimated0. .

Final estimates of 0 are are not not close close to to boundaries. boundaries.

GOF plots do not indicate unexplained trends.

PCT/EP2019/071699

37

A final model that did not meet these criteria might be accepted only after careful consideration of

the modeling strategy and study objectives.

The predictive performance of a final model was evaluated by prediction-corrected visual predictive

check (pcVPC) (Bergstand, AAPS J. 2011; 13: 143-51) and calculating the percentage of the

observations outside the 90% prediction intervals (PI). In addition to the pcVPC, the final model

was also evaluated by bootstrapping technique (Ette, Journal of clinical pharmacology. 1997, 37

(6): 486-95). At least 200 bootstrap replications were performed and the associated mean

parameter estimates and their corresponding 95% confidence interval (CI) were derived from the

replicates.

1.6 Individual post-hoc Pharmacokinetic parameters

The individual systemic exposures of baloxavir (S-033447), such as Cmax, C, thethe area area under under thethe

plasma concentration-time curve from time zero to infinity (AUCo-inf), and CC24 (AUC-inf), and after after a single a single dose dose of of

baloxavir marboxil (S-033188) were calculated using individual post-hoc PK parameters with

empirical Bayesian estimations of the final model. Also, these exposures were calculated using

individual post-hoc PK parameters with empirical Bayesian estimations of the simulation model.

The formulae needed to calculate the exposure metrics depends on the model structure.

1.7 Monte-Carlo Simulation

Monte-Carlo simulation was employed with the final model to assess the relationship between

body body weight weightand PK PK and parameters (Cmax, parameters (C,AUCO-inf, AUC-inf,andand C24). C).A Athousand virtual thousand pediatric virtual patients pediatric were patients were

generated for every 5 kg by simulating the body weight (10 to < 60 kg) based on the final model to

be assumed as a uniform distribution for body weight.

Also, Monte-Carlo simulation was employed with the simulation model to assess the relationships

between age (0 months to < 2 years old) and PK parameters (Cmax, AUCO-inf (C, AUC-inf, andand C).C24). A thousand A thousand

virtual pediatric patients were generated for every month old by simulating the age based on the

simulation model. The relationship between age and body weight for Japanese pediatrics followed

the database by Ministry of Health, Labour and Welfare ( Ministry of Health, Labour and Welfare.

Research for growth of babies (2010). URL: http://www.e-

stat.go.jp/SG1/estat/Xlsdl.do?sinfid=000012673573). To generate stat.go.jp/SG1/estat/Xlsdl.do?sinfid=000012673573) virtual virtual To generate pediatricpediatric patients, patients, log- log-

normal distribution was assumed for body weight and geometric mean and its coefficient of

variance were set for each month (Table 3), and 1:1 proportion was assumed for gender. MF was

calculated for each month by equation 8 assuming that all pediatric patients are full-term delivery

and their ages are middle in the age range. For example, a pediatric patient with 6 months old,

his/her PMA is 40 weeks + 6.5 months = 68.2 weeks.

WO wo 2021/028024 PCT/EP2019/071699

38 Table 3: The Relationships between Age and Body Weight for Birth to < 2 Years Old Pediatrics

(a) Boys

Percentile Assumed Maturation Age (months) 3 10 25 25 50 75 90 97 97 Geometric Mean Factor CV% 0 to 1 2.55 2.91 3.23 3.23 3.57 3.89 4.17 4.47 3.57 17.8 0.551 1 to 2 3.53 3.94 4.35 4.79 5.22 5.59 5.96 4.79 16.3 0.620 2 to 3 4.41 4.88 5.34 5.84 6.33 6.76 7.18 7.18 5.84 14.9 0.679 3 to 4 5.12 5.61 6.10 6.63 7.16 7.62 7.62 8.07 6.63 13.8 0.728 4 to 5 5.67 6.17 6.17 6.67 7.22 7.76 8.25 8.25 8.72 7.22 12.8 0.770 5 to 6 6.10 6.60 6.60 7.10 7.66 8.21 8.71 9.20 7.66 12.1 0.804 6 to 7 6.44 6.94 6.94 7.44 8.00 8.56 9.07 9.57 8.00 11.5 0.832 7 to 8 6.73 7.21 7.71 8.27 8.84 9.36 9.87 8.27 11.0 0.856 8 to 9 6.96 7.44 7.94 8.50 9.08 9.61 9.61 10.14 8.50 10.7 10.7 0.875 9 to 10 7.16 7.64 8.13 8.13 8.70 9.29 9.83 10.37 8.70 10.4 0.892 10 to 11 7.34 7.81 8.31 8.88 9.48 10.03 10.59 8.88 10.1 0.905 11 11 to to 12 12 7.51 7.98 8.48 9.06 9.67 10.23 10.23 10.82 9.06 10.0 0.917 12 to 13 7.68 8.15 8.65 8.65 9.24 9.86 10.44 11.04 9.24 9.8 9.8 0.927 13 to 14 7.85 8.32 8.32 8.83 8.83 9.42 10.05 10.65 11.28 11.28 9.42 9.7 9.7 0.935 14 to 15 8.02 8.49 8.49 9.00 9.60 10.25 10.86 11.51 9.60 9.6 9.6 0.942 15 15 to to 16 16 8.19 8.67 8.67 9.18 9.79 10.44 11.08 11.08 11.75 9.79 9.5 0.949 16 to 17 8.36 8.84 9.35 9.97 10.64 11.29 11.98 9.97 9.4 9.4 0.954 17 to 18 8.53 9.01 9.53 10.16 10.84 11.51 12.23 10.16 9.3 0.958 18 to 19 8.70 9.18 9.71 10.35 11.04 11.73 11.73 12.47 10.35 9.2 0.963 19 to 20 8.86 9.35 9.89 10.53 10.53 11.25 11.95 12.71 10.53 9.2 0.966 20 to 21 9.03 9.52 10.06 10.72 11.45 12.17 12.96 10.72 9.1 0.969 21 to 22 9.19 9.69 10.24 10.91 11.65 12.39 13.20 10.91 10.91 9.1 0.972 22 to 23 9.36 9.86 10.41 10.41 11.09 11.85 12.61 13.45 11.09 9.1 0.974 23 to 24 9.52 10.03 10.03 10.59 11.28 12.06 12.83 13.69 13.69 11.28 9.0 9.0 0.977

WO wo 2021/028024 PCT/EP2019/071699 PCT/EP2019/071699

39 (b) Girls

Percentile Assumed Maturation Age (months) 3 10 25 50 75 90 97 97 Geometric Mean Factor CV% 00 to to 11 2.52 2.82 2.82 3.10 3.41 3.71 3.98 4.25 4.25 3.41 16.2 0.551

11 to to 22 3.39 3.39 3.73 4.08 4.47 4.86 5.20 5.54 4.47 14.8 0.620 2 to 3 4.19 4.58 4.58 4.97 5.42 5.42 5.86 6.27 6.27 6.67 6.67 5.42 13.7 0.679 3 to 4 4.84 5.25 5,67 5.67 6.15 6.64 7.08 7.08 7.53 6.15 12.8 0.728 4 to 5 5.35 5.77 6.21 6.71 7.23 7.23 7.70 7.70 8.18 6.71 12.1 0.770 5 to 6 5.74 6.17 6.62 6.62 7.14 7.67 7.67 8.17 8.67 7.14 11.6 0.804 6 to 7 6.06 6.49 6.95 7.47 7.47 8.02 8.53 8.53 9.05 7.47 11.2 0.832 7 to 8 6.32 6.32 6.75 7.21 7.75 7.75 8.31 8.83 9.37 9.37 7.75 10.8 0.856 8 to 9 6.53 6.97 7.43 7.97 7.97 8.54 9.08 9.63 7.97 7.97 10.6 0.875 9 to 10 6.71 7.15 7.62 7.62 8.17 8.17 8.74 9.29 9.85 8.17 8.17 10.5 0.892 10 to 11 6.86 7.31 7.78 7.78 8.34 8.93 8.93 9.49 10.06 8.34 8.34 10.3 0.905 11 11 to to 12 12 7.02 7.02 7.46 7.46 7.95 8.51 9.11 9.11 9.68 10.27 8.51 10.3 0.917 12 to 13 7.16 7.62 8.11 8.68 9.29 9.87 10.48 10.48 8.68 8.68 10.2 0.927 13 to 14 7.31 7.77 7.77 8.27 8.85 8.85 9.47 10.07 10.69 8.85 10.2 0.935 14 to 15 7.46 7.93 8.43 9.03 9.66 10.27 10.27 10.90 9.03 9.03 10.1 0.942 15 to 16 7.61 8.08 8.60 9.20 9.85 10,47 10.47 11.12 9.20 10.1 0.949 16 to 17 7.75 8.24 8.24 8.76 9.38 10.04 10.04 10.67 11.33 9.38 10.1 0.954 17 to 18 7.90 7.90 8.39 8.93 9.55 10.23 10.87 10.87 11.55 9.55 10.1 0.958 18 to 19 8.05 8.55 9.09 9.73 10.42 10.42 11.08 11.77 9.73 9.73 10.1 0.963 19 to 20 8.20 8.20 8.71 9.26 9.91 10.61 11.28 11.28 11.99 9.91 10.1 0.966 20 to 21 8.34 8.34 8.86 8.86 9.43 10.09 10.09 10.81 11.49 12.21 10.09 10.1 0.969 21 to 22 8.49 8.49 9.02 9.59 10.27 11.00 11.70 11.70 12.44 10.27 10.2 0.972 22 to 23 8.64 8.64 9.18 9.18 9.76 10.46 11.20 11.92 11.92 12.67 10.46 10.2 0.974 23 to 24 8.78 9.34 9.93 10.64 11.40 12.13 12.90 10.64 10.2 0.977

2. Software

PK calculations were performed by using WinNonlin (Version 6.2.1). SAS (Version 9.2) was used

for statistical analyses. R (Version 3.0.2) was used for PK/PD analysis. NONMEM (Version 7.3),

Intel Visual FORTRAN Compiler (version 2010), and Perl-speaks-NONMEM (version 4.2) were

used for population PK analysis.

Example 2: Population pharmacokinetic parameters

A population PK model has been developed to describe baloxavir PK in both Japanese and non-

Japanese influenza patients (adults and adolescents) who are otherwise healthy (T0821 and

T0831). The relationship between drug exposure and various covariates has been explored. The

population PK model parameters are summarised in Table 4. Likewise, a paediatric population PK

model has been developed to describe the population PK of baloxavir in Japanese otherwise

healthy patients aged 66months monthsto to<<12 12years years(Study (StudyT0822, T0822,also alsocalled called1618T0822; 1618T0822;and andStudy Study

T0833, also called 1705T0833). The population PK model parameters in paediatrics are summarised in Table 5.

wo 2021/028024 WO PCT/EP2019/071699 PCT/EP2019/071699

40 Table 4: Population Pharmacokinetic Parameters in Adults (report S-033188-CB-272-N)

Pharmacokineti C parameter Units Estimate RSE (%) IIV (%)

CL/F L/hr 5.40 1.5 38.7

Vc/F L L 333 2.7 2.7 54.8

Q/F L/hr 6.27 4.5 - -

Vp/F L 212 2.3 2.3 22.2

Ka 1/hr 1.10 1.10 6.5 6.5 111.8 hr 0.32 3.6 ALAG -

CL/F (L/hr) CL/F (L/hr)= = 5.40 x (body 5.40 weight/64.8) X (body 1.04 x1.72 weight/64.8) 1.04Non-Asian x (ALT/17) X-0.115 x1.72 Non-Asian ,-0.115 , where (ALT/17) Non-Asian where Non-Asian = 1 for Non-Asian and Non-Asian = 0 for Asian 1.76 Vc/F (L) Vc/F (L) = = 333 333 x x (body (body weight/64.8) weight/64.8) x 1.76 X Non-Asian 1.36 1.36 Non-Asian Q/F (L/hr) Q/F (L/hr) = = 6.27 6.27 x X (body weight/64.8) 0.473 0.473 (body weight/64.8)

Vp/F (L) = 212 x (body weight/64.8) 0.642

Ka (hr ¹ = 1.10 x 0.613 gender, where gender = 1 for female and gender = 0 for male (hr¹) Effect of Effect offood on on food bioavailability = 0.869 bioavailability fed fed where = 0.869 fed fed where = 1 when = 1 dosing < 2 hours when dosing < 2before hoursorbefore after or after

food intake and fed = 0 when dosing 22hours hoursbefore beforeor orafter afterfood foodintake intake Abbreviations: ALAG, absorption lag time; CL/F, apparent total clearance; Ka, first-order rate of

absorption; Q/F, apparent inter-compartmental clearance; Vc/F, apparent volume of central compartment; Vp/F, apparent volume of peripheral compartment.

Table 5: Population Pharmacokinetic Parameters in Japanese paediatrics- studiesT0822 studies (1618T0822) and T0833 (1705T0833)

Pharmacokinetic Units Estimate RSE (%) IIV (%) parameter CL/F L/hr 2.72 5.4 5.4 22.7

Vc/F L 117 11.9 -

Q/F L/hr 1.06 36.7 -

Vp/F L 67.1 34.4 -

1/hr 0.702 17.9 128.1 Ka hr hr 0.47 4.1 ALAG CL/F (L/hr) = 2.72 X (body weight/20.7) 0.77 0.77 CL/F (L/hr) = 2.72 x (body weight/20.7) 1.07 Vc/F (L) Vc/F (L)= =117 x(body 117 weight/20.7) x(body 1.07 weight/20.7) Q/F (L/hr) = 1.06 x (body weight/20.7) 0.77 1.07 1.07 Vp/F (L) = 67.1 x(body weight/20.7) Relative bioavailability for 10-mg tablet = 0.88 (fixed)

Abbreviations: ALAG, absorption lag time; CL/F, apparent total clearance; Ka, First-order rate of

absorption; Q/F,apparent inter-compartmental clearance; Vc/F, apparent volume of central compartment; Vp/F, apparent compartment;Vp/F, apparent volume volume of of peripheral peripheral compartment. compartment.

Baloxavir PK was found to be linear with respect to dose in both adults and paediatrics. PK was

found to be well described using a two-compartment model with first-order absorption with a lag-

time and first order elimination from the central compartment. In adults, baloxavir demonstrated low

oral clearance of 5.4 L/hr (Japanese). Both bodyweight and race (Asian versus non-Asian) were

found to be significant covariates on CL/F. At the same bodyweight, CL/F was on average 1.7 fold

higher in non-Japanese. Interestingly, a similar but slightly lower ethnic effect was seen on volume

(V/F), suggesting the covariate may not solely reflect a difference in absolute bio-availability (F). In

Japanese paediatrics, bodyweight was a significant covariate on both clearance and volume.

Population median oral clearance was about 3 L/h for a Japanese child weighing 24 kg. Oral drug

clearance and inter-compartmental clearance scaled to bodyweight with an allometric exponent of

0.632, whereas both central and peripheral volume terms scaled with their typical exponent

approaching 1. Based on these allometric relationships, bodyweight-adjusted oral drug clearance

(L/hr/kg) decreases with increasing bodyweight and can be estimated to be about 2-fold lower in a

10-kg child compared to an adult of 70 kg. Furthermore, because volume of distribution scaled

roughly proportional to bodyweight (i.e., approximately constant on a per kg basis), disposition half-

life increases with increasing bodyweight.

Example 3: Dose finding for non-Asian (e.g. white) paediatric patients

A single dose administration will be used, as supported by adult and adolescent phase 2/3 studies

as well as phase 3 Japanese paediatric studies, where a single oral dose administration was

confirmed to provide rapid and sustained relief of influenza symptoms.

Optimal doses for two non-Asian paediatric patient groups (patient group 1: birth to <1 year, and

patient group 2: 1 to <12 years) were simulated. The optimal doses were simulated to match adult

exposures exposuresininterms of of terms total drug drug total exposure (AUCinf), exposure C24 and CC72, (AUCinf), andwhile not exceeding C, while adult Cmax. not exceeding In C· In adult

the Japanese phase 2, global phase 3 studies and Japanese paediatric studies, baloxavir marboxil

has shown a consistent and substantial drop in viral titres within 24 hours post dose. This supports

the selection of C24 C asas the the primary primary PKPK metric metric for for acute acute viral viral killing killing and and use use ofof this this metric metric toto inform inform

exposure-matching to adults. However, because an adequate level of drug exposure beyond 24

hours may play a role to sustain inhibition of viral replication, model simulations also ensured the

selected doses would adequately match adult exposure in terms of overall drug exposure (e.g.,

AUCinf AUCinf and andC72). C). AA link linkbetween betweenviral rebound viral and less rebound sustained and less drug exposure sustained over time over drug exposure (shorter time (shorter

T1/2 relative to adults) cannot be ruled out at this point.

Simulations of the anticipated drug exposure in non-Japanese paediatric subjects were obtained

from the Japanese population PK model (Section 1.2, Table 5) with the following two optimizations:

(1) The disposition parameters CL/F and Vc/F obtained in Japanese paediatric patients were

scaled by respectively 1.72 and 1.36, to account for the anticipated ethnic effect in these

parameters as estimated from the global adult population PK model (Section 1.2, Table 4). A

more detailed explanation of the factors 1.72 and 1.36 for accounting for the ethnic effect in

pharmacokinetics pharmacokinetics of of baloxavir baloxavir marboxil marboxil can can be be found found in in Koshimichi, Koshimichi, Hiroki, Hiroki, et et al. al. "Population "Population

WO wo 2021/028024 PCT/EP2019/071699 PCT/EP2019/071699

42 Pharmacokinetic and Exposure-Response Analyses of Baloxavir Marboxil in Adults and

Adolescents Including Patients With Influenza." Journal of pharmaceutical sciences (2018).

(2) (2) AA literature-based literature-based maturation maturation factor factor (MF) (MF) was was used used to to reduce reduce CL/F CL/F parameter parameter in in an an attempt attempt to to

mimic ontogeny and select conservative doses in neonates and infants. MF was expressed as

MF = PMAy / (PMAy + TM50y), where PMA is postmenstrual age (weeks), TM50 is maturation

half-life (54.2 weeks) until 50% maturation, and y Y is Hill coefficient (3.92). The maturation

factor (MF) is described, e.g. in Anderson, Paediatr Anaesth. 2011; 21: 222-37.

Model-based simulations (accounting for ethnic effect as well as bodyweight) indicated a regimen

of 2 mg/kg up to 20 kg and 40 mg above 20 kg can be expected to mimic adult drug exposure

adequately adequatelyininterms of of terms AUCinf, C24 and AUCinf, C72 Cand C and waswas and selected in paediatrics selected older than in paediatrics older3 months than 3 for months for

studies CP40559 (Study 1) and CP40563 (Study 2). Furthermore, simulations confirm that this

regimen can contain Cmax below C below thethe current current upper upper limit limit of of exposure exposure achieved achieved andand confirmed confirmed to to be be

safe in humans SO so far. For younger infants (<3 (< 3months), months),where whereincomplete incompleteenzyme enzymematuration maturation

cannot fully be ruled out to slightly reduce overall drug clearance, simulations are supportive that

baloxavir marboxil dosing at 1 mg/kg is sufficient for adequate matching of drug exposure to adults.

Further details on the simulations which led to optimal doses for non-Asian (e.g. white such as

Caucasian) paediatric patients are given in Examples 4 and 5, below.

Example 4: Simulations for optimal doses for non-Asian pediatric patients (1-12 years old)

The three dosing regimens explored were based on patient weight:

(1) 1 mg/kg < 40 kg, 40 mg flat > 40 40 kg kg (previously (previously proposed proposed regimen), regimen),

(2) 1.5 mg/kg < 25 kg, 40 mg flat 25 25kg, kg,and and

(3) 2.0 mg/kg < 20 kg, 40 mg flat > 20 20 kg. kg.

Of note, each regimen is tailored to the weight at which body weight (BW)-based dosing will stop,

thereby managing risk to exceed 40 mg (adult reference dose). The projected pediatric drug

exposure for various BW groups in terms of total drug exposure (AUCo-inf), peak drug (AUC-inf), peak drug exposure exposure

(Cmax), (C), andand drug drug concentration concentration at at 24 24 hours hours andand 72 72 hours hours after after dosing dosing is is depicted depicted in in Figure Figure 1, 1,

Figure 2, Figure 3, and Figure 4, respectively. Adult reference exposure distributions for efficacy

are shown for adults globally, and separated out for Caucasians and Asians. The thorough QT

(TQT) study in Asians provides the current safe upper limit of exposure achieved in humans SO so far.

In this regard, Q and T are two peaks in an electrocardiogram and if the distance between the two

peaks changes during a clinical study it can indicate a drug's cardiac liability. In other words "TQT" measures side effects of the drug investigated on the heart (see, e.g., Grenier, Drug, healthcare and patient safety 10 (2018): 27).

As shown in previous studies, oral drug clearance of baloxavir is characterized to scale

allometrically with an exponent of 0.632 on BW in Asian Pediatrics. Based on this relationship, BW-

adjusted oral drug clearance (L/hr/kg) was estimated to be about 2-fold lower in a 10-kg child

compared to an adult of 70 kg. In agreement with these calculations, the herewith provided

simulation confirms that regimen three (i.e. regimen (3) shown above) matches adult exposure

optimally in terms of both total drug exposure (Figure 1) as well as drug levels up to 72 hours after

dosing (Figure 4), particularly in pediatrics with a BW less than 25 kg. In light of the higher drug

clearance and, hence, a faster disposition in children, a higher dose per BW (compared to adults)

can also sustain drug exposure until at least 72 hours after dosing at similar levels as seen in

adults. It can, however, be appreciated from Figure 4 that the improved exposure matching of

regimen three (relative to regimen one) on AUCO-inf and C72 AUC-inf and C72 comes comes at at the the expense expense of of an an increase increase

in Cmax (Figure C (Figure 2) 2) andand C24 (Figure C (Figure 3) of3) of about about 2-fold 2-fold (relative (relative to regimen to regimen one).one). Nonetheless, Nonetheless,

average peak drug levels will remain below the levels measured in the adult thorough QT (TQT)

study.

The optimal regimen should present the highest benefit-risk profile based on available data, and

thus balances risks of compromised efficacy and safety. A single dose of baloxavir marboxil has

been well tolerated in both adults and Asian pediatrics, and a substantial and consistent reduction

in viral titers has been seen over a wide dose range, indicating a wide therapeutic window. In line

with this wide window, no clear relationship has been found between drug exposure and

occurrence of adverse events. Moreover, as baloxavir was well tolerated in the TQT study (with

highest peak and total drug exposures SO so far achieved in human), it appears reasonable to

consider the exposure data of this study as the best estimate of a safe upper limit of exposure in

humans.

In the recently completed study using 1 mg/kg of baloxavir marboxil was used in Asian pediatrics

weighing less than 20 kg. Our simulations support that more adequate exposure matching to adults

can can be be achieved achievedin in terms of both terms totaltotal of both (AUCo-inf) and sustained (AUC-inf) (C72) drug and sustained (C)exposure using either drug exposure using either

regimen two or three (i.e. regimen (2) or (3) specified above). Regimen three however mimics adult

exposure better than regimen two, while both regimens can contain exposure with sufficient

confidence within a reliable benchmark shown to be safe in adults.

Of note, in addition to our simulations, the available sparse PK data in the recently completed

Asian pediatric study 1602T0833 (enrolling pediatrics weighing less than 20 kg) confirms drug

concentrations briefly after dosing to fluctuate at about the mean of 100 ng/mL (1 mg/kg). Since PK

is known to be linear with dose, a dose of 2 mg/kg can be expected to increase exposure by a

WO wo 2021/028024 PCT/EP2019/071699

44 factor of 2. It appears reasonable therefore to propose regimen three (i.e. regimen (3) specified

above): 2 mg/kg for patients weighing up to 20 kg (and 40 mg flat for patients weighing more than

20 kg).

Example 5: Simulations for optimal doses for non-Asian pediatric patients (0-1 year old)

The three dosing regimens explored were:

(1) 1 mg/kg (previously proposed regimen),

(2) 1.5 mg/kg, and

(3) 2.0 mg/kg.

Simulation of pediatric drug exposure distribution in terms of AUCO-inf, AUCo-inf, Cmax, C, C, C24, and Cand areC72 are

depicted in Figure 5, Figure 6, Figure 7, and Figure 8 respectively.

In agreement with the simulations for 1-12 year old children, regimen three (i.e. regimen (3)

specified above) matches adult exposure most optimally in terms of total drug exposure (AUCo-inf) (AUC-inf)

and C72, C, atat least least for for infants infants aged aged 3 3 months months and and older. older. For For the the younger younger infants infants (<(< 3 3 months), months), where where

incomplete enzyme maturation might slightly reduce overall drug clearance, simulations are

supportive that baloxavir marboxil dosing at 1 mg/kg is sufficient for adequate matching of AUCo-inf AUC-inf

to adults. In infants older than 3 months, the overall increase in AUCo-inf using regimen AUC-inf using regimen three three is is

also also expected expectedto to improve matching improve of drug matching of exposure to adults drug exposure to in terms in adults of C72 (Figure terms of C 8), but with (Figure 8), but with

an approximate 2-fold increase in terms of Cmax compared C compared to to regimen regimen oneone (Figure (Figure 6).6). Of Of note, note,

since baloxavir has low oral drug clearance, in addition to a demonstrated age-independent

absolute bio-availability (similar Cmax C in in adults adults andand children children seen seen in in Asian Asian patients patients at at 1 mg/kg), 1 mg/kg), C Cmax

predictions can be made with fairly high confidence across age-groups (note also that the volume

of distribution is demonstrated to be proportional to BW).

Taken together, these simulations support the ability to improve benefit-risk assessment for infants

of 3 months and older with a regimen of 2 mg/kg, while the reduced dose of 1 mg/kg is considered

sufficient for younger infants (4 weeks-3 months) as well as for newborns (0-4 weeks).

Example 6: Preparation of granulae comprising the compound of the invention

A. Preparation of granulae compositions

A compound II can be produced, e.g., by a method disclosed in International Publication No. WO

2016/175224.

PCT/EP2019/071699

45

Manufacturing Method for Compound /

O OH O MeO MeO O O O N O N. N N N zu O N N. N O N

F S S F F S S F F Il Il I

Potassium carbonate (1483.4 mg, 10.7 mmol), potassium iodide (549.5 mg, 3.3 mmol), tetrahydrofuran (33.1 g), N,N-dimethylacetamide (3.8 g) and water (80.3 mg) were added to the

compound Il (4.0 g, 8.3 mmol), followed by stirring. The resultant mixture was heated to 60°C, to

which chloromethyl methyl carbonate (1758.9 mg, 14.2 mmol) was added. The resultant was

stirred at 60°C for 9 hours, and then cooled to 20°C. Acetic acid (822.0 mg), 2-propanol (3.1 g)

and water (20.0 g) were added thereto, and the resultant was extracted twice with tetrahydrofuran

(1.8 g, 8.9 g g). g). The The solvent solvent was was distilled distilled off off through through vacuum vacuum concentration concentration toto a a liquid liquid weight weight ofof

about 32 g. The resultant was heated to 45°C, 2-propanol (1.6 g) was added thereto, and the

resultant was cooled to 20°C. A sodium acetate aqueous solution prepared from sodium acetate

(339.0 mg) and water (46.0 g) was added thereto, followed by cooling to 5°C. After the resultant

was stirred at 5°C for 3 hours, a pale yellow precipitate was filtered off. The thus obtained solid

was washed with a mixture of 2-propanol (4.7 g) and water (6.0 g), and the solid was then washed

again with 2-propanol (6.3 g). To the thus obtained pale yellow solid, dimethyl sulfoxide (30.9 g)

was added, followed by stirring. The resultant was heated to 60°C, to which a mixture of dimethyl

sulfoxide (2.2 g) and water (4.8 g) was added. A mixture of dimethyl sulfoxide (19.9 g) and water

(28.4 g) was further added thereto, followed by cooling to 20°C 20°C.After Afterthe theresultant resultantwas wasstirred stirredat at

20°C for 3 hours, a generated white precipitate was filtered off. The thus obtained solid was

washed with a mixture of dimethyl sulfoxide (8.0 g) and water (4.8 g), and the solid was washed

again with water (12.0 g). The thus obtained solid was dried to give a compound I (4.21 g) as

white crystal.

1 H-NMR (DMSO-D6) 1H-NMR (DMSO-D6) :: 2.91-2.98 2.91-2.98 (1H, (1H, m), m), 3.24-3.31 3.24-3.31 (1H, (1H, m), m), 3.44 3.44 (1H, (1H, t, t, JJ == 10.4 10.4 Hz), Hz), 3.69 3.69 (1H, (1H,

dd, J = 11.5, 2.8 Hz), 3.73 (3H, s), 4.00 (1H, dd, J = 10.8, 2.9 Hz), 4.06 (1H, d, J = 14.3 Hz), 4.40

(1H, d, J = 11.8 Hz), 4.45 (1H, dd, J = 9.9, 2.9 Hz), 5.42 (1H, dd, J = 14.4, 1.8 Hz), 5.67 (1H, d, J =

6.5 Hz), 5.72-5.75 (3H, m), 6.83-6.87 (1H, m), 7.01 (1H, d, J = 6.9 Hz), 7.09 (1H, dd, J = 8.0, 1.1

Hz), 7.14-7.18 (1H, m), 7.23 (1H, d, J = 7.8 Hz), 7.37-7.44 (2H, m)

WO wo 2021/028024 PCT/EP2019/071699 PCT/EP2019/071699

46 Powder X-ray Diffraction: 20 (°: (°):Characteristic Characteristicpeaks peaksare arepresent presentat at8.6° 0.2°, 14.1° 8.6°±0.2°, 0.2°, 14.1°±0.2°, 17.4°+0.2°, 17.4°±0.2°, 20.0°+0.2°, 20.0°±0.2°, 24.0° 0.2°, 26.3° 24.0°±0.2°, 0.2 o 29.6°+0.2° 26.3°±0.2°, 29.6°±0.2° and 35.4°+0.2°. 35.4°±0.2°.

The powder X-ray diffraction pattern of the crystal of compound I is shown in Figure 10.

(1) Study on Stabilizer

In order to study a stabilizer, a stabilizer shown in each of Tables 7 to 9 and a compound

represented by formula (I) were wet-granulated, and the amount of increase in the compound

represented by formula (II), which is a related substance, were evaluated after a temporal stability

test of the produced granule. A preparation having a formulation shown in Table 6 was produced

by the stirring granulation method.

[Table 6]

Content (mg)

Compound represented by Formula (I) 2.0

Purified White Sugar 488.0

Hydrogenated HydrogenatedMaltose Starch Maltose Syrup Starch (Maltitol) Syrup (Maltitol) 500.0

Stabilizer 30.0

Hydroxypropyl Cellulose 10.0

Total 1030.0

(Method for Manufacturing Preparation)

A compound represented by formula (I), purified white sugar, powdered hydrogenated maltose

starch syrup (maltitol), a stabilizer and hydroxypropyl cellulose shown in Table 6 were mixed using

a high-speed mixer (FS-GS SJT 10 high-speed mixer, Fukae Powtec Co., Ltd.), and water was

added to the mixture, followed by stirring granulation. Then, the granulation product was subjected

to to size size selection selection in in aa power power mill mill (model (model P-3S, P-3S, Showa Showa Kagakukikai Kagakukikai Co., Co., Ltd.), Ltd.), and and the the resultant resultant was was

dried at 65 to 70°C in a fluidized bed granulator (WSG2&5 fluid bed dryer granulator, Okawara

Mfg. Co., Ltd.). After drying, a granule was obtained by size selection in a power mill (model P-3S,

Showa Kagakukikai Co., Ltd.). Granulation conditions in the high-speed mixer were as follows:

(Granulation Conditions)

- Granulator: FS-GS SJT 10 high-speed mixer

- Rotational Speed of Agitator: 250 rpm

- Rotational Speed of Chopper: 2500 rpm

- Acceleration in Solution Injection: 21 + ± 2 g/min

- Moisture: 4 to 6.5% by weight

- Mashing time: 1 min + ± 5 sec

(Temporal Stability Test of Preparation) wo 2021/028024 WO PCT/EP2019/071699 PCT/EP2019/071699

47 The produced preparation was stored at 60°C for 2 weeks, and the amount of increase in the

compound represented by formula (II), which is a related substance, was measured.

(Stabilizer)

As shown in Tables 7 to 9, sodium chloride (Kanto Chemical Co., Inc.), potassium chloride (Wako

Pure Chemical Industries, Ltd.), ascorbic acid (Nacalai Tesque, Inc.), fumaric acid (Merck KGaA),

medium-chain fatty acid triglyceride Miglyol (Mitsuba Trading Co., Ltd.), triethyl citrate (Merck

KGaA), sodium nitrite (Nacalai Tesque, Inc.), glycerin (Kanto Chemical Co., Inc.), and vitamin E

(Merck KGaA) were used as the stabilizer.

[Table 7]

Example 7-1 Example 7-2 Example 7-3 Example 7-4

Potassium Stabilizer Sodium Chloride Ascorbic Acid Fumaric Acid Chloride

[Table 8]

Example 7-5 Example 7-6 Comparative Comparative

Example 7-1 Example 7-2

Medium-Chain Fatty Acid Triethyl Stabilizer Sodium Nitrite Glycerin Triglyceride Miglyol Citrate

[Table 9]

Comparative Comparative

Example 7-3 Example 7-4

Stabilizer Vitamin E None

(Method for Measuring Compound represented by Formula (II))

The amount of the compound represented by formula (II) was measured by liquid chromatography

by employing the following method and conditions:

- Detector: ultraviolet absorptiometer (measurement wavelength: 260 nm)

- Column: XBridge C18, 3.5 um, µm, 3.0 X 150 mm

- Column temperature: constant temperature around 35°C

- Mobile Phase A: 0.1% trifluoroacetic acid/0.2 mM EDTA solution, Mobile Phase B:

acetonitrile

- - Delivery of mobile phase: controlled for a concentration gradient with a mixing ratio

between the mobile phase A and the mobile phase B changed as shown in Table 10.

[Table 10]

Time after Injection (min) Mobile Phase A (vol%) Mobile Phase B (vol%)

0 - 5 70 30 0 5 5 40 40 70 20 70 20 30 80 30 80 40 40.1 20 70 20 70 80 30 80 30

- Flow rate: about 0.6 mL/min

- Injection amount: 5 ul µL

- Sample cooler temperature: about 5°C

- Washing solution for autoinjector: acetonitrile/methanol mixture (1:3)

- Range of area measurement: 50 minutes after injection of sample solution

- Equation for calculating amount of compound represented by formula (II):

Amount Amount of ofcompound compoundrepresented by formula represented (II) (%) by formula = (ATII (II) (%) =/ (ATII EAT) X /100 x 100

ATII: peak area of compound represented by formula (II) in sample solution

EAT: : SumSum of of peak peak areas areas of of sample sample solution solution (excluding (excluding blank blank andand system system peaks) peaks)

(Results)

The amount of increase (%) in the compound represented by formula (II) in the temporal stability

test of the preparations of Examples 7-1 to 7-6 and Comparative Examples 7-1 to 7-4 is shown in

Tables 11 to 13. As a result, the amount of increase (%) in the compound represented by formula

(II) in the granules of Examples 7-1 to 7-6 was lower than that in the granule containing no

stabilizer of Comparative Example 7-4. Particularly, the amount of increase in the compound

represented by formula (II) in the granules containing sodium chloride of Example 7-1, ascorbic

acid of Example 7-3, fumaric acid of Example 7-4 and medium-chain fatty acid triglyceride Miglyol

of Example 7-5 was much smaller than that in the granule containing no stabilizer of Comparative

Example 7-4.

[Table 11]

Example 7-1 Example 7-2 Example 7-3 Example 7-4

Potassium Stabilizer Sodium Chloride Ascorbic Acid Fumaric Acid Chloride Chloride

Amount of Increase

(%) in Compound 0.70 1.31 0.28 0.30 represented by

Formula (II)

[Table 12]

Example 7-5 Example 7-6 Comparative Comparative

Example 7-1 Example 7-2

Medium-Chain Fatty Triethyl Stabilizer Sodium Nitrite Glycerin Acid Triglyceride Citrate

WO wo 2021/028024 PCT/EP2019/071699 PCT/EP2019/071699

49 Miglyol

Amount of Increase

(%) in Compound 0.34 1.24 6.63 9.95 represented by

Formula (II)

[Table 13]

Comparative Comparative

Example 7-3 Example 7-4

Stabilizer Vitamin E None Amount of Increase (%) in Compound 3.56 1.35 represented by Formula (II)

(2) Study on Excipient

In order to study an excipient, an excipient shown in each of Tables 14 to 16 and a compound

represented by formula (I) were wet-granulated, and the amount of increase in the compound

represented by formula (II), which is a related substance, was evaluated after a temporal stability

test of the produced granule.

(Method for Producing Preparation)

An excipient shown in each of Tables 14 to 16 and a compound represented by formula (I) were

mixed mixed in in aa bag bag at at aa ratio ratio of of 1:1, 1:1, and and then, then, the the mixture mixture was was sieved sieved through through aa 30-mesh 30-mesh sieve sieve (wire (wire

diameter: 0.22 mm). The sieved mixed powder was mixed in a mortar, and then, purified water

was gradually added such that moisture in granulation was about 5% by weight based on the

charged amount of the materials, and the resultant was kneaded using a pestle. The kneaded

product was subjected to wet size selection while pressed by hand through 16-mesh wires (wire

diameter: 0.55 mm). The granulation product after the size selection was dried in a vented dryer,

and a granule was prepared while pressed by hand through 20-mesh wires (wire diameter: 0.40

mm).

(Temporal Stability Test of Preparation)

The produced preparation was stored at 60°C for 2 weeks, and the amount of increase in the

compound represented by formula (II), which is a related substance, was measured.

(Excipient)

WO wo 2021/028024 PCT/EP2019/071699

50 As shown in Tables 14 to 16, purified white sugar (Merck KGaA), hydrogenated maltose starch

syrup (maltitol, ROQUETTE), D-mannitol (ROQUETTE), lactose hydrate (DMV-Fonterra Excipients

GmbH & Co. KG), sorbitol (Merck KGaA), erythritol (ROQUETTE), xylitol (ROQUETTE), and

isomalt (Beneo-Palatinit GmbH) were used as the excipient

[Table 14]

Example 7-7 Example 7-8 Example 7-9

Hydrogenated Maltose Excipient Purified White Sugar D-Mannitol Starch Syrup (Maltitol)

[Table 15]

Reference Example 7-1 Reference Example 7-2 Reference Example 7-3

Excipient Lactose Hydrate Sorbitol Erythritol

[Table 16]

Reference Example 7-4 Reference Example 7-5

Excipient Xylitol Isomalt Isomalt

(Results)

The amount of increase (%) in the compound represented by formula (II) in the temporal stability

test of the preparations of Examples 7-7 to 7-9 and Reference Examples 7-1 to 7-5, and the

melting point of each excipient are shown in Tables 17 to 19. As a result, the amount of increase

(%) in the compound represented by formula (II) in the granules of Examples 7-7 to 7-9 was

slightly lower than that in the granules of Reference Examples 7-1, 7-2 and 7-5. The amount of

increase (%) in the compound represented by formula (II) in the granules of Reference Examples

7-3 and 7-4 was almost the same as that in the granules of Examples 7-7 to 7-9, whereas the

melting point was lower as compared with Examples 7-7 to 7-9 and thus, there was a possibility of

sticking. Accordingly, it was regarded that purified white sugar, hydrogenated maltose starch syrup

(maltitol) and D-mannitol are preferred as the excipient.

[Table 17]

Example 7-7 Example 7-8 Example 7-9

Excipient Purified White Sugar Hydrogenated D-Mannitol

Maltose Starch

Syrup (Maltitol)

Melting point (C) (°C) 160 186 145 166 168 Amount of Increase (%) 0.08 0.06 0.11 in Compound

WO wo 2021/028024 PCT/EP2019/071699 51 51

represented by Formula (II)

[Table 18]

Reference Example Reference Reference

7-1 Example 7-2 Example 7-3

Excipient Lactose Hydrate Sorbitol Erythritol

Melting point (C) (°C) 201 202 95 121

Amount of Increase (%)

in Compound 0.17 0.15 0.08 represented by Formula (II) (II)

[Table 19]

Reference Example Reference

7-4 Example 7-5

Excipient Xylitol Isomalt

Melting point (C) 141 (°C) 92 96 141- 161 161

Amount of Increase (%) in

Compound represented by 0.04 0.38

Formula (II)

(3) Study on Combination of Excipients

Although purified white sugar, hydrogenated maltose starch syrup (maltitol) and D-mannitol were

selected as a preferable excipient, in order to study a combination of these excipients, a

combination of excipients shown in each of Tables 20 and 21 and a compound represented by

formula (I) were wet-granulated, and the produced granule was evaluated for (a) the amount of

increase in the compound represented by formula (II), which is a related substance, (b)

suspensibility in water, (c) container adherence adherence,(d) (d)aafine finegranule granuleyield, yield,and and(e) (e)aabulk bulkdensity. density.AA

preparation having a formulation shown in each of Tables 20 and 21 was produced by the stirring

granulation method.

201

[Table 20]

Example 7-10 Example 7-11 Example 7-12

(weight mg) (weight mg) (weight mg)

Compound represented by 10.0 20.0 10.0

Formula (I)

Maltitol 300.0 350.0 490.0

D-Mannitol 614.0 554.0 490.0

Purified White Purified WhiteSugar Sugar - - -

Sodium Chloride 30.0 30.0 -

Polyvinyl Pyrrolidone 10.0 10.0 10.0 k25 Total 964.0 964.0 1000.0

Weight Ratio of Sugar Maltitol: Maltitol: Maltitol:

or Sugar Alcohol D-Mannitol = D-Mannitol = D-Mannitol = 32.8:67.2 38.7:61.3 38.7:61.3 50.0:50.0 50.0:50.0

[Table 211 21]

Comparative Comparative

Example 7-5 Example 7-6

(weight mg) (weight mg)

Compound represented by 10.0 10.0 Formula (I)

Maltitol 500.0 -

D-Mannitol - 500.0

Purified White Purified WhiteSugar Sugar 480.0 480.0

Sodium Chloride - -

Polyvinyl Pyrrolidone k25 10.0 10.0

Total 1000.0 1000.0

Weight Ratio of Sugar or Maltitol: D-Mannitol: D-Mannitol:

Sugar Alcohol Purified White Sugar = Purified White Sugar =

51.0:49.0 51.0:49.0

(Method for Producing Preparation)

A compound represented by formula (I), an excipient and polyvinyl pyrrolidone shown in each of

Tables 20 and 21 were mixed using a high-speed mixer (LFS-GS-2J high-speed mixer, Fukae

Powtec Co., Ltd.), and water was added to the mixture, followed by stirring granulation. Then, the

granulation product was subjected to size selection in a power mill (model P-3S, Showa

Kagakukikai Co., Ltd.), and the resultant was dried at 65 to 70°C in a fluidized bed granulator (MP-

01 Fluid bed dryer granulator, Powrex Corp.). After drying, a granule was obtained by size

PCT/EP2019/071699

53 selection in a power mill (model P-3S, Showa Kagakukikai Co., Ltd.). Granulation conditions in the

high-speed mixer were as follows:

(Granulation (Granulation Conditions) Conditions)

- Granulator: LFS-GS-2J high-speed mixer

- Rotational Speed of Agitator: 333 rpm

- Rotational Speed of Chopper: 2500 rpm

- Acceleration in Solution Injection: 20 + ± 3.5 g/min

- Moisture: 3 to 7.5% by weight

- Mashing time: 1 to 2 min + ± 5 sec

(Suspensibility Test of Preparation in Water)

The number of times of mix by inversion required for preparing a visually uniform suspension when

9.5 mL of water was added to about 1 g of the present preparation was recorded.

(Container Adherence of Preparation)

In the production of the present preparation, the amount of a granulation product adhering to the

interior wall of a stirring granulator after granulation was visually confirmed. The presence or

absence of adhesion after scraping off was evaluated as an index for container adherence.

(Fine Granule Yield Measurement of Preparation)

100 g of the present preparation was sieved through Nos. 30 and 140 sieves, and the ratio of the

amount of a granule passing through the No. 30 sieve and remaining on the No. 40 sieve to the

total amount of the sieved granule was calculated.

(Bulk Density Measurement of Preparation)

The present preparation was injected to a container (capacity: 100 mL) until overflowing, and the

preparation was carefully leveled off to remove an excess from the upper surface of the container.

The value of a preparation weight in the container was obtained from a container weight tared in

advance, and a bulk density was determined according to the following equation:

Bulk density = Preparation weight in container / 100

(Excipient)

As shown in Tables 20 and 21, purified white sugar (Merck KGaA), hydrogenated maltose starch

syrup (maltitol, ROQUETTE), and D-mannitol (ROQUETTE) were used in combination as the

excipient.

(Results) wo 2021/028024 WO PCT/EP2019/071699 54 54 The suspensibility in water, container adherence, fine granule yield and bulk density of the preparations of Examples 7-10 to 7-12 and Comparative Examples 7-5 and 7-6 are shown in

Tables 22 and 23. As a result, the preparations of Examples 7-10 to 7-12 containing a mixture of

hydrogenated maltose starch syrup (maltitol) and D-mannitol as an excipient had excellent

suspensibility in water, small adherence to a container, and a bulk density of 0.5 g/mL or larger.

Particularly, in Examples 7-10 and 7-11, the fine granule yield was also as high as 90% or more.

On the other hand, the preparations of Comparative Examples 7-5 and 7-6 containing a mixture of

purified white sugar and hydrogenated maltose starch syrup (maltitol) or purified white sugar and

D-mannitol as an excipient were inferior in suspensibility in water to Examples and also had large

container adherence. Particularly, in Comparative Example 7-6, the fine granule yield was also

low.

[Table 22]

Example 7-10 Example 7-11 Example 7-12

Suspensibility in Water Uniformly Uniformly Uniformly

suspended by 15 suspended by 10 suspended by by times times 10 times

Container Adherence Small Small Small

Fine Fine Granule GranuleYield (%)(%) Yield 92 90 72 Bulk Density (g/mL) 0.67 0.67 0.59

[Table 23]

Comparative Comparative

Example 7-5 Example 7-6

Suspensibility in Water Uniformly suspended by 25 Uniformly suspended by

times 30 times

Container Adherence Large Large

Fine Granule Yield (%) 89 66 Bulk Bulk Density Density(g/mL) (g/mL) 0.76 0.76 0.65

(4) Study on Binder

In order to study a binder, a binden binder shown in Table 24 and a compound represented by formula (I)

were wet-granulated, and the produced preparation was evaluated for (a) the amount of increase

in the compound represented by formula (II), which is a related substance, after a temporal stability

test and (b) a bulk density. A preparation having a formulation shown in Table 24 was produced by

the stirring granulation method. Polyvinyl pyrrolidone K25 (BASF) and hydroxypropyl cellulose SL

(Shin-Etsu Chemical Co., Ltd.) were used as the binder.

WO wo 2021/028024 PCT/EP2019/071699

55

[Table 24]

Example 7-13 Example 7-14 Reference

(weight mg) (weight mg) Example 7-6

(weight mg)

Compound represented by Formula (I) 10.0 10.0 10.0 10.0 10.0

Purified White Sugar 480.0 460.0 480.0

Hydrogenated Maltose Starch syrup 500.0 500.0 500.0 (Maltitol)

Polyvinyl Pyrrolidone K25 10.0 30.0 -

Hydroxypropyl Cellulose SL - - - 10.0 10.0

Total 1000.0 1000.0 1000.0

(Method for Producing Preparation)

A compound represented by formula (I), purified white sugar, hydrogenated maltose starch syrup

(maltitol), and hydroxypropyl cellulose SL (Nippon Soda Co., Ltd.) or polyvinyl pyrrolidone K25 as a

binder shown in Table 24 were mixed using a high-speed mixer (LFS-GS-2J high-speed mixer,

Fukae Powtec Co., Ltd.), and water was added to the mixture, followed by stirring granulation.

Then, the granulation product was subjected to size selection in a power mill (model P-3S, Showa

Kagakukikai Co., Ltd.), and the resultant was dried at 65 to 70°C in a fluidized bed granulator (MP-

01 Fluid bed dryer granulator, Powrex Corp.). After drying, a granule was obtained by size

selection in a power mill (model P-3S, Showa Kagakukikai Co., Ltd.). Granulation conditions in the

high-speed mixer were as follows:

(Granulation Conditions)

- Granulator: LFS-GS-2J high-speed mixer

- Rotational Speed of Agitator: 333 rpm

- Rotational Speed of Chopper: 2500 rpm

- Acceleration in Solution Injection: 20 + ± 3.5 g/min

- Moisture: 3 to 7.5% by weight

± 5 sec - Mashing time: 1 to 2 min +

(Temporal Stability Test of Preparation)

The produced preparation was stored at 60°C for 2 weeks, and the amount of increase in the

compound represented by formula (II), which is a related substance, was measured.

(Bulk Density Measurement of Preparation)

The present preparation was injected to a container (capacity: 100 mL) until overflowing, and the

preparation was carefully leveled off to remove an excess from the upper surface of the container.

WO wo 2021/028024 PCT/EP2019/071699

56 The value of a preparation weight in the container was obtained from a container weight tared in

advance, and a bulk density was determined according to the following equation:

Bulk density = Preparation weight in container / 100

(Results)

The amount of increase (%) in the compound represented by formula (II) in the temporal stability

test of the preparations of Examples 7-13 and 7-14 and Reference Example 7-6, and the bulk

density are shown in Table 25. As a result, the amount of increase (%) in the compound

represented by formula (II) in the preparations of Examples 7-12 and 7-13 containing polyvinyl

pyrrolidone was lower than that in the preparation of Reference Example 7-6 containing

hydroxypropyl cellulose. The amount of increase (%) in the compound represented by formula (II)

in the temporal stability test and the bulk density in the preparation of Example 7-12 in which the

amount of polyvinyl pyrrolidone was 1% by weight were lower than those in the preparation of

Example 7-13 in which the amount of polyvinyl pyrrolidone was 3% by weight.

[Table 25]

Example 7-13 Example 7-14 Reference

Example 7-6

Amount of Increase (%) in Compound 0.12 0.15 0.20 represented by Formula (II)

Bulk Density (g/mL) 0.72 0.77 -

(5) Study on Fluidizing Agent

In order to study a fluidizing agent, (a) the amount of related substances after temporal storage of

a preparation and (b) stickiness between preparations were evaluated. A preparation having a

formulation shown in each of Tables 26 and 27 was produced by the stirring granulation method.

1% and 3% light anhydrous silicic acid (Cab-o-sil, Cabot Corp.), 1% and 3% hydrated silicon

dioxide (RxCIPIENTS) and 1% and 3% sodium stearyl fumarate (PRUV, JRS Pharma) were used

as the fluidizing agent.

[Table 26]

Example 7-15 Example 7-16 Example 7-17

(weight mg) (weight mg) (weight mg)

Compound represented by Formula (I) 10.0 10.0 10.0

Hydrogenated Maltose Starch Syrup 490.0 490.0 490.0 (Maltitol)

D-Mannitol 490.0 490.0 490.0

Polyvinyl Pyrrolidone k25 10.0 10.0 10.0 wo 2021/028024 WO PCT/EP2019/071699 PCT/EP2019/071699

57 Sucralose 5.0 5.0 5.0 5.0

Light Anhydrous Silicic Acid 10.0 10.0 30.0 -

Hydrated Silicon Dioxide - - 10.0

Sodium Stearyl Fumarate - - -

Strawberry Flavor 1.0 1.0 1.0

Total 1016.0 1036.0 1016.0

[Table 27]

Example 7-18 Comparative Comparative

(weight mg) Example 7-7 Example 7-8

(weight mg) (weight mg)

Compound represented by Formula 10.0 10.0 10.0 (I)

Hydrogenated Maltose Starch Syrup 490.0 490.0 490.0 (Maltitol)

D-Mannitol 490.0 490.0 490.0

Polyvinyl Pyrrolidone k25 10.0 10.0 10.0

Sucralose 5.0 5.0 5.0 5.0

Light Anhydrous Silicic Acid - - 10.0

Hydrated Silicon Dioxide 30.0 - -

Sodium Stearyl Fumarate - 10.0 10.0 30.0

Strawberry Flavor 1.0 1.0 1.0

Total 1036.0 1016.0 1036.0

(Method for Producing Preparation)

A compound represented by formula (I), hydrogenated maltose starch syrup (maltitol), D-mannitol,

polyvinyl pyrrolidone K25, sucralose, a fluidizing agent (any of light anhydrous silicic acid, hydrated

silicon dioxide, and sodium stearyl fumarate) and strawberry flavor shown in each of Tables 26 and

27 were mixed using a high-speed mixer (LFS-GS-2J high-speed mixer, Fukae Powtec Co., Ltd.),

and water was added to the mixture, followed by stirring granulation. Then, the granulation product

was subjected to size selection in a power mill (model P-3S, Showa Kagakukikai Co., Ltd.), and the

resultant was dried at 65 to 70°C in a fluidized bed granulator (MP-01 Fluid bed dryer granulator,

Powrex Corp.). After drying, a granule was obtained by size selection in a power mill (model P-3S,

Showa Kagakukikai Co., Ltd.). Granulation conditions in the high-speed mixer were as follows:

(Granulation Conditions)

- Granulator: LFS-GS-2J high-speed mixer

- Rotational Speed of Agitator: 333 rpm

- Rotational Speed of Chopper: 2500 rpm wo 2021/028024 WO PCT/EP2019/071699 PCT/EP2019/071699

58 - Acceleration in Solution Injection: 20 + 3.5 g/min

- Moisture: 3 to 7.5% by weight

± 5 sec - Mashing time: 1 to 2 min +

(Temporal Stability Test of Preparation)

The produced present preparation was stored at 60°C for 2 weeks, and the amount of increase in

the compound represented by formula (II), which is a related substance, was measured.

(Stickiness Test of Preparation)

1 g of the preparation was charged into a 4 mL brown bottle, and evaluation was made as follows:

good (indicated by circle), the preparation present at the bottom fluidized when the bottle was

inverted three times; fair (indicated by triangle), the preparation present in an upper part fluidized

when the bottle was inverted three times; and poor (indicated by x-mark), the preparation did not

fluidize when the bottle was inverted three times.

(Results)

The amount of increase (%) in the compound represented by formula (II) in the temporal stability

test of the preparations of Examples 7-15 to 7-18 and Comparative Examples 7-7 and 7-8, and the

stickiness between preparations are shown in Tables 28 and 29. As a result, the amount of

increase (%) in the compound represented by formula (II) in the preparations of Examples 7-15 to

7-18 was almost the same as that in the preparations of Comparative Examples 7-7 and 7-8

containing sodium stearyl fumarate, and was almost the same even when the amount of the

fluidizing agent was changed.

Meanwhile, as a result of studying the stickiness of the preparations of Examples 7-15 to 7-18 and

Comparative Examples 7-7 and 7-8, the preparations of Examples 7-15 to 7-18 had smaller

stickiness than that of the preparations of Comparative Examples 7-7 and 7-8.

[Table 28]

Example 7-15 Example 7-16 Example 7-17

Amount of Increase (%) in Compound 0.64 0.51 0.34 represented by Formula (II)

Stickiness O O

[Table 29]

Comparative Comparative Example 7-18 Example 7-7 Example 7-8

Amount of Increase (%) in Compound 0.58 0.51 0.45 represented by Formula (II)

Stickiness x o

(6) Study on Suspending Agent

In order to study a suspending agent, the suspensibility of a preparation in water was evaluated.

The present preparation having a formulation shown in Table 30 was produced by the stirring

granulation method. Hypromellose (TC-5, Shin-Etsu Chemical Co., Ltd.), hydroxypropyl cellulose

(HPC-L, Nippon Soda Co., Ltd.), and methyl cellulose (SM-4, Shin-Etsu Chemical Co., Ltd.) were

used as the suspending agent.

[Table 30]

Example 7-19 Reference Reference Comparative

(weight mg) Example 7-7 Example 7-8 Example 7-9

(weight mg) (weight mg) (weight mg)

Compound represented by 20.0 20.0 20.0 20.0

Formula (I)

D-Mannitol 564.0 564.0 564.0 564.0

Hydrogenated Maltose 350.0 350.0 350.0 353.0 Starch Syrup (Maltitol)

Sodium Chloride 30.0 30.0 30.0 30.0

Polyvinyl Pyrrolidone 10.0 10.0 10.0 10.0

Hypromellose 3.0 3.0 - - - - -

Hydroxypropyl - 3.0 - - - Cellulose

Methyl Cellulose - 3.0 - -

Sucralose 5.0 5.0 5.0 5.0 5.0 5.0 5.0

Light Anhydrous Silicic 20.0 20.0 20.0 20.0 Acid

Strawberry Flavor 1.0 1.0 1.0 1.0

Total 1003.0 1003.0 1003.0 1003.0

(Method (Methodfor forProducing Preparation) Producing Preparation)

A compound represented by formula (I), D-mannitol, hydrogenated maltose starch syrup (maltitol),

sodium chloride and polyvinyl pyrrolidone K25 shown in Table 30 were mixed using a vertical

granulator (model VG-50, Powrex Corp.), and water was added to the mixture, followed by stirring

granulation. Then, the granulation product was subjected to size selection in a power mill (model

P-3S, Showa Kagakukikai Co., Ltd.), and the resultant was dried at 65 to 70°C in a fluidized bed

granulator (GPGC-15&30 fluid bed dryer granulator, Powrex Corp.). After drying, size selection wo 2021/028024 WO PCT/EP2019/071699

60 was performed in a power mill (model P-3S, Showa Kagakukikai Co., Ltd.). The granulation

product after the size selection was mixed with sucralose, a suspending agent (any of

hypromellose, hydroxypropyl cellulose, and methyl cellulose), light anhydrous silicic acid and

strawberry flavor using a V-shaped mixer (130 L V type blender, manufactured by Tokuju Corp.) to

obtain a granule.

(Granulation Conditions)

- Granulator: vertical granulator VG-50

- Rotational Speed of Agitator: 200 rpm

- Rotational Speed of Chopper: 2500 rpm

- Acceleration in Solution Injection: 105 + ± 3 g/min

- Moisture: 4.5 to 7.5% by weight

- Mashing time: 1 to 3 min + ± 5 sec

(Suspensibility Test of Preparation in Water)

1 g of the present preparation was added into a stoppered container containing 9.5 ml mL of water,

and the stoppered container was reciprocally inverted 40 times, and immediately thereafter, a

liquid was collected from upper and lower parts of the container. After the completion of container

inversion, the container was left at room temperature for 10 minutes, and a liquid was collected

from a central part of the container. The concentration of the compound represented by formula (I)

in the collected liquids was measured.

(Method for Measuring Compound represented by Formula (I))

The amount of the compound represented by formula (I) was measured by liquid chromatography

by employing the following method and conditions:

- Detector: ultraviolet absorptiometer (measurement wavelength: 260 nm)

- Column: ACQUITY UPLC BEH C18 1.7 um, µm, 2.1 X 50 mm (Waters Corp.)

- Column temperature: constant temperature around 35°C

- Mobile Phase A: 0.1% trifluoroacetic acid/0.2 mM EDTA solution, Mobile Phase B:

acetonitrile acetonitrile

- - Delivery of mobile phase: controlled for a concentration gradient with a mixing ratio

between the mobile phase A and the mobile phase B changed as shown in Table 31

[Table 31]

Time after Injection (min) Mobile Phase A (vol%) Mobile Phase B (vol%)

0 -2.3 0 2.3 62 38 2.3 - 33 2.3 62 -> 20 38 -> 80 62 20 38 80 3 4 20 80

- Flow rate: about 0.6 mL/min

PCT/EP2019/071699 61

- Injection amount: 4 ul µL

- Sample cooler temperature: about 5°C

- Washing solution for autoinjector: acetonitrile

- Range of area measurement: 8 minutes after injection of sample solution

- Equation for calculating amount of compound represented by formula (I):

Amount of compound represented by formula (I) (%) = MS / C xAT / As x 100

MS: weighed amount (mg)

C: labeled amount in preparation (mg/mL)

As: peak area obtained from standard solution

AT: peak area obtained from sample solution

(Evaluation of Suspensibility in Water)

The suspensibility of the preparation was evaluated according to the following equation:

Ratio (%) of amount of compound represented by formula (I) in suspension at central position of

container after 10 minutes from container inversion = (Concentration of compound represented by

formula (I) in suspension at central position of container after 10 minutes from container inversion /

Concentration of compound represented by formula (I) in suspension at central position of

container immediately after container inversion) x 100 (%)

(Results)

The suspensibility in water of the preparations of Example 7-19, Reference Examples 7-7 and 7-8

and Comparative Example 7-9 is shown in Table 32. As a result, the ratio of the amount of the

compound represented by formula (I) in the suspensions of Example 7-19 and Reference Examples 7-7 and 7-8 was higher than that in the suspension of Comparative Example 7-9

containing no suspending agent. Particularly, the preparation of Example 7-19 containing

hypromellose had a high ratio of the amount of the compound represented by formula (I) in the

suspension and had good suspensibility in water.

[Table 32]

Example 7-19 Reference Reference Comparative

Example 7-7 Example 7-8 Example 7-9

Ratio (%) of amount of 95.1 93.0 92.9 65.8

compound represented by formula (I) in suspension at

central position of

container after 10 minutes

from container inversion

(7) Study on Lubricant

In order to study a lubricant, an angle of repose was evaluated as an index for fluidity of a

preparation. A preparation having a formulation shown in Table 33 was produced by the stirring

granulation method. Talc (Merck KGaA, LUB) was used as the lubricant.

[Table 33]

Example 7-20 Comparative

(weight mg) Example 7-10

(weight mg)

Compound represented by Formula 20.0 20.0 (I)

D-Mannitol 560.0 561.0

Powdered Hydrogenated Maltose 350.0 350.0 Starch Syrup (Maltitol)

Sodium Chloride 30.0 30.0

Polyvinyl Pyrrolidone 10.0 10.0

Hypromellose 3.0 3.0

Sucralose 5.0 5.0

Light Anhydrous Silicic Acid 20.0 20.0

Talc 1.0 -

Strawberry Flavor 1.0 1.0

Total 1000.0 1000.0

(Method for Producing Preparation)

A compound represented by formula (I), D-mannitol, hydrogenated maltose starch syrup (maltitol),

sodium chloride, polyvinyl pyrrolidone K25, and hypromellose shown in Table 33 were mixed using

a vertical granulator (model FM-VG50, Powrex Corp.), and water was added to the mixture,

followed by stirring granulation. Then, the granulation product was subjected to size selection in a

power mill (model P-3S, Showa Kagakukikai Co., Ltd.), and the resultant was dried at 65 to 70°C in

a fluidized bed granulator (GPGC-15&30 fluid bed dryer granulator, Powrex Corp.). After drying,

size selection was performed in a power mill (model P-3S, Showa Kagakukikai Co., Ltd.). The

granulation product after the size selection was mixed with talc, sucralose, light anhydrous silicic

acid and strawberry flavor using a V-shaped mixer (130 L V type blender, Tokuju Corp.) to obtain a

granule.

(Granulation Conditions)

- Granulator: vertical granulator VG-50

- Rotational Speed of Agitator: 200 rpm

- Rotational Speed of Chopper: 2500 rpm

- Acceleration in Solution Injection: 105 + ± 3 g/min

- Moisture: 4.5 to 7.5% by weight

- Mashing time: 1 to 3 min + 5 sec

(Measurement of Angle of Repose of Preparation)

The angle of repose of the produced preparation was measured using a powder tester (Hosokawa

Micron Group) under the following conditions:

Operation time: 170 sec, Slow down: 10 sec, Amplitude: 1.5 mm

(Results)

The angle of repose of the preparations of Example 7-20 and Comparative Example 7-10 is shown

in Table 34. As a result, the preparation of Example 7-20 containing talc had a smaller angle of

repose than that of the preparation of Comparative Example 7-10 containing no talc, demonstrating

that the fluidity of the preparation can be enhanced by containing talc.

[Table 34]

Example 7-20 Comparative

Example 7-10

Angle of Repose (°) 33.7 36.2

(8) Measurement of Release Rate

The preparation of Example 7-20 shown in Table 33 was stored at 60°C for 2 weeks and at 40°C

and 75% relative humidity for 2 weeks, and the release rate of the compound represented by

formula (I) was measured.

(Dissolution Property Test of Preparation)

The produced preparation was stored at 60°C for 2 weeks and at 40°C and 75% relative humidity

for 2 weeks, and the release rate of the compound represented by formula (I) was measured by

the second method of Dissolution Test described in the Japanese Pharmacopoeia (paddle

method). The fluid used in the method of Dissolution Test was the dissolution test second fluid

(containing 1% Tween 20), and the rotational speed of the paddle was set to 50 rpm.

(Results)

As shown in Figure 2, the release rate from the preparation of Example 7-20 after storage at 60°C

for 2 weeks and after storage at 40°C and 75% relative humidity for 2 weeks hardly differed from

the release rate from the preparation immediately after preparation.

WO wo 2021/028024 PCT/EP2019/071699

64 (9) Preparation having different composition ratio

Example 7-21 shown in Tables 34 was prepared in the same manner of Example 7-20 by the

stirring granulation method.

[Table 35]

Example 7-21

(weight mg)

Compound represented by Formula (I) 40.0

D-Mannitol 540.0

Powdered Hydrogenated Maltose Starch Syrup 350.0 (Maltitol)

Sodium Chloride 30.0

Polyvinyl Pyrrolidone 10.0 10.0

Hypromellose 3.0 3.0

Sucralose 5.0 5.0

Light Anhydrous Silicic Acid 20.0

Talc 1.0

Strawberry Flavor 1.0

Total 1000.0

B. Preparation of granules which are optimized for the preparation of an oral suspension

Granules which are optimized for the preparation of an oral suspension have been prepared. The

granulated powder was manufactured via a standard wet granulation process. The detailed

composition of the granules for oral suspension is shown Table 1 and the rationale for use of the

excipients is provided. The excipients and their amounts are known to be suitable for the intended

paediatric populations from 0 to < 18 years of age. The granulae can easily be reconstituted with

water. More specifically, 2 g granulae, which contain 40 mg of baloxavir marboxil (nominal) can be

reconstituted with 20 mL water, which corresponds to a final concentration of 2 mg of the

compound /mL.

The detailed composition of the granules for oral suspension is shown Table 36.

Table 36: Components and Composition of Baloxavir marboxil Granules for Oral

Suspension

Component Nominal Nominal Concentration Function Quality Standard amount in Granule in Granule

(mg/bottle) (%)

Active Baloxavir Marboxil 40 2 In-house standard ingredient

Mannitol 1120 56 Diluent Ph. Eur./USP/JP

Maltitol Diluent Ph. Eur./NF/JPE 700 35 Taste

Sodium Chloride 60 3 masking Ph. Eur./USP/JP

agent

Hypromellose 6 0.3 Dispersant Ph. Eur./USP/JP

Povidone 1 Povidone(K(Kvalue: 25)25) value: 20 Binder Ph. Eur./USP/JP

Silica, Colloidal 40 2 Fluidizer Ph. Eur./NF/JP Anhydrous Sucralose 10 10 0.5 Sweetener Ph. Eur./NF/JPE

Talc 2 0.1 Lubricant Lubricant Ph. Eur./USP/JP

Strawberry Flavour 2 0.1 Flavour In-house standard

Purified Water a Vehicle Ph. Eur./USP/JP - - - - Total Weight b 2,000 100 100 - - - a Purified water is removed during manufacturing process.

b An overfill of, e.g. 0.13 g of granules is applied to obtain the targeted maximum extractable

volume of 20 mL after reconstitution; fill weight may be adjusted based on assay value for bulk

granules.

Bitter taste has been reported in adult clinical studies with baloxavir marboxil and several

excipients have been included in the formulation to mask the bitter taste and ensure palatability,

such as sodium chloride, sucralose and strawberry flavour. Thus, the granulae provided herewith

have the advantages that they are to be administered in the form of an oral suspension and that

the bitter taste of the active compound is masked. Accordingly, these granulae improve

acceptance of the compound in paediatric patients, which contributes to the achievement of the

therapeutic effect.

Example 7: Global phase III study investigating one-dose baloxavir marboxil (XOFLUZA) in children with the flu

Methods:

WO wo 2021/028024 PCT/EP2019/071699 PCT/EP2019/071699

66 miniSTONE-2 was a phase III, global multicenter, randomized, double-blind, active-

controlled study in otherwise healthy paediatric patients with influenza, conducted during

the 2018/19 season mainly in the US. The study evaluated the safety (primary objective),

pharmacokinetics (PK) and efficacy (secondary objective) of one-dose of baloxavir

marboxil (granular formulation for suspension) in otherwise healthy children aged 1 to less

than 12 years with influenza. More specifically, the effect of baloxavir marboxil was

compared to the effect of oseltamivir. The influenza infection was confirmed by a rapid

influenza diagnostic test and displaying influenza-like symptoms (a temperature of 38°C or

over, and one or more respiratory symptoms).

Patients were randomized 2:1 to receive either a weight-based single oral dose of

baloxavir marboxil or standard oral dose of oseltamivir (twice-daily dosing for five days).

More specifically, participants enrolled in the study were recruited in parallel into two

cohorts: patients aged five to less than 12 years and patients aged one to less than 5

years. Patients in both cohorts were randomly assigned to receive one-dose of baloxavir

marboxil (2mg/kg for patients under 20kg or 40mg for patients 20kg or over) or oseltamivir

twice a day over five days (dosing according to body weight).

The primary endpoint was the proportion of patients with adverse events or severe

adverse events up to study day 29. Secondary endpoints include pharmacokinetics (PK),

time to alleviation of influenza signs and symptoms, and duration of symptoms, including

fever and time to cessation of viral shedding by virus titer for virology.

Results in summary:

This study investigated the safety (primary objective), pharmacokinetics and efficacy of a

single dose of baloxavir marboxil in otherwise healthy children aged 1 to < 12 years with

influenza. The study showed that baloxavir marboxil (XOFLUZA), given as a new oral

suspension, is a well-tolerated and effective potential treatment for the flu in otherwise

healthy children aged one to less than 12 years.

The obtained results can be summarized as follows.

Baloxavir was well tolerated and no new safety signals were identified

no SAEs

No relevant differences in demographics or clinical baseline characteristics

were noticed between baloxavir and oseltamivir groups

median age 6 years; 53% female; 85% Caucasian; no relevant differences

observed between baloxavir and oseltamivir groups

Pharmacokinetic data

initial 'lead in' PK indicated baloxavir exposure to be consistent with adults

and adolescents

Baloxavir showed comparable efficacy compared with oseltamivir in Time To

Alleviation of Influenza Signs and Symptoms (TASS) endpoint

TASS uses cough, nasal symptoms, return to daycare/school/normal activities (from parent/carer questionnaire) and fever

TASS: baloxavir 138 hrs (CI 116.6, 163.2); oseltamivir 150 hrs (CI 115.0,

165.7) 165.7)

TASS was an exploratory endpoint and did not undergo statistical testing.

The almost identical confidence intervals indicate comparable efficacy

between treatment treatmennt

Clear difference in Time To Cessation of Viral Shedding

There was a clear difference in the median Time to Cessation of Viral

Shedding between baloxavir (24 hrs) and Oseltamivir (76 hrs); delta 56 hrs.

These data continue to suggest that baloxavir-treated patients are no longer

infective after a median time of 1 day compared to 3 days in oseltamivir-

treated patients. This may be of significance to the reduction of onward

transmission of influenza.

Results in detail:

The study assessed baloxavir marboxil versus an active comparator (oseltamivir) in

children aged between one and less than 12 years with the flu.

WO wo 2021/028024 PCT/EP2019/071699 PCT/EP2019/071699

68

Of the 176 paediatric patients recruited, 124 formed the ITTi population (baloxavir

marboxil, n=81 vs oseltamivir, n=43), 89.7% of which had an influenza A infection (65.5%

H3N2, 24.1% H1N1). No SAEs, deaths or adverse events of special interest were

observed and the safety profile of baloxavir marboxil was consistent with that observed in

clinical studies to date. The median time to alleviation of influenza signs and symptoms

observed in the BXM group (138 hours [95% CI; 116.6,163.2]) was comparable to the

oseltamivir group (150 hours [95% CI; 115.0,165.7]). Consistent with previous phase III

studies, there was a clear difference in the median time to cessation of viral shedding

between baloxavir marboxil (24.2 hours [95% CI; 23.5,24.6]) and oseltamivir (75.8 hours

[95% CI; 68.9,97.8]).

Thus, the phase III miniSTONE-2 study met its primary endpoint, demonstrating that

baloxavir marboxil (XOFLUZA) is well-tolerated in children with the flu. As described

above, the study also showed that baloxavir marboxil is comparable to oseltamivir - a

proven effective treatment for children with the flu - at reducing the duration of flu

symptoms, including fever.

Conclusion:

A single, oral dose of baloxavir marboxil was well tolerated and effective for the treatment

of influenza in otherwise healthy paediatric patients aged between 1 and < 12 years. The

MINISTONE-2 study showed that baloxavir marboxil (XOFLUZA), given as a new oral

suspension, is a well-tolerated and effective potential treatment for the flu in otherwise

healthy children aged one to less than 12 years.

wo 2021/028024 WO PCT/EP2019/071699

69 The present invention refers to the following nucleotide and amino acid sequences:

SEQ ID NO:1: Influenza A virus (A/WSN/1933(H1N1)): GenBank:X17336.1, (A/WSN/1933(H1N1): GenBank: X17336.1,comprising comprisingthe the138T 138T

mutation. The 138T mutation is underlined and shown in bold face.

MEDFVRQCFNPMIVELAEKAMKEYGEDLKIETNKFAATCTHLEVCFMYSDFHFIDEQGESIVVELG DPNALLKHRFEIIEGRDRTIAWTVINSICNTTGAEKPKFLPDLYDYKKNRFIEIGVTRREVHIYYLEKA DPNALLKHRFEIEGRDRTIAWTVINSICNTTGAEKPKFLPDLYDYKKNRFIEIGVTRREVHIYYLEKA NKIKSEKTHIHIFSFTGEEMATKADYTLDEESRARIKTRLFTIRQEMASRGLWDSFRQSERGEETIE NKIKSEKTHIHIFSFTGEEMATKADYTLDEESRARIKTRLFTIRQEMASRGLWDSFRQSERGEETIE ERFEITGTMRKLADQSLPPNFSSLENFRAYVDGFEPNGYIEGKLSQMSKEVNARIEPFLKSTPRPL ERFEITGTMRKLADQSLPPNFSSLENFRAYVDGFEPNGYIEGKLSQMSKEVNARIEPFLKSTPRPL RLPDGPPCSQRSKFLLMDALKLSIEDPSHEGEGIPLYDAIKCMRTFFGWKEPNVVKPHEKGINPNY RLPDGPPCSQRSKFLLMDALKLSIEDPSHEGEGIPLYDAIKCMRTFFGWKEPNVVKPHEKGINPNY LLSWKQVLAELQDIENEEKIPRTKNMKKTSQLKWALGENMAPEKVDFDDCKDVGDLKQYDSDER LLSWKQVLAELQDIENEEKIPRTKNMKKTSQLKWALGENMAPEKVDFDDCKDVGDLKQYDSDEP ELRSLASWIQNEFNKACELTDSSWIELDEIGEDAAPIEHIASMRRNYFTAEVSHCRATEYIMKGVYI NTALLNASCAAMDDFQLIPMISKCRTKEGRRKTNLYGFIIKGRSHLRNDTDVVNFVSMEFSLTDP NTALLNASCAAMDDFQLIPMISKCRTKEGRRKTNLYGFIIKGRSHLRNDTDVVNFVSMEFSLTDPR LEPHKWEKYCVLEVGDMLLRSAIGHVSRPMFLYVRTNGTSKIKMKWGMEMRRCLLQSLQQIESM LEPHKWEKYCVLEVGDMLLRSAIGHVSRPMFLYVRTNGTSKIKMKWGMEMRRCLLOSLQQIESMI EAESSVKEKDMTKEFFENKSETWPVGESPKGVEEGSIGKVCRTLLAKSVFNSLYASPQLEGFSAE EAESSVKEKDMTKEFFENKSETWPVGESPKGVEEGSIGKVCRTLLAKSVENSLYASPQLEGFSAD SRKLLLIVQALRDNLEPGTFDLGGLYEAIEECLINDPWVLLNASWFNSFLTHALR SRKLLLIVQALRDNLEPGTFDLGGLYEAIEECLINDPVVVLLNASWFNSFLTHALR

SEQ ID NO:2: Sequence fraction of the influenza A virus (A/WSN/1933(H1N1)): GenBank: (A/WSN/1933(H1N1): GenBank: X17336.1, comprising the 138T mutation. The 138T mutation is underlined and shown in bold face.

FAATCTH

Claims (17)

1. A method for treating an influenza virus infection, wherein said method comprises administering an effective amount of a compound to a patient having an influenza virus infection, wherein the compound has one of the following formulae I and II: 22051576_1 (GHMatters) P118017.AU

(I) (II) 2019461218

, , or is a pharmaceutically acceptable salt thereof, and wherein the following dosage is used: (i) in a patient that is younger than 1 year: (a) if the patient is younger than 4 weeks, then the effective amount is 0.8-1.2 mg/kg body weight, optionally about 1 mg/kg body weight; (b) if the patient is 4 weeks or older but younger than 3 months, then the effective amount is 0.8-1.2 mg/kg body weight, optionally about 1 mg/kg body weight; (c) if the patient is 3 months or older but younger than 12 months, then the effective amount is 1.8-2.2 mg/kg body weight, optionally about 2 mg/kg body weight; (ii) in a patient that is 1 year or older but younger than 12 years: (a) if the patient has a body weight of less than 20 kg, then the effective amount is 1.8- 2.2 mg/kg body weight, optionally about 2 mg/kg body weight; or (b) if the patient has a body weight of 20 kg or more, then the effective amount is 35-45 mg, optionally about 40 mg.

2. Use of a compound in the manufacture of a medicament for treating an influenza virus infection in a patient, wherein the compound has one of the following formulae I and II: (I) (II)

22051576_1 (GHMatters) P118017.AU

22051576_1 (GHMatters) P118017.AU

, , 2019461218

or is a pharmaceutically acceptable salt thereof, and wherein the following dosage is used: (i) in a patient that is younger than 1 year: (a) if the patient is younger than 4 weeks, then the effective amount is 0.8-1.2 mg/kg body weight, optionally about 1 mg/kg body weight; (b) if the patient is 4 weeks or older but younger than 3 months, then the effective amount is 0.8-1.2 mg/kg body weight, optionally about 1 mg/kg body weight; (c) if the patient is 3 months or older but younger than 12 months, then the effective amount is 1.8-2.2 mg/kg body weight, optionally about 2 mg/kg body weight; (ii) in a patient that is 1 year or older but younger than 12 years: (a) if the patient has a body weight of less than 20 kg, then the effective amount is 1.8- 2.2 mg/kg body weight, optionally about 2 mg/kg body weight; or (b) if the patient has a body weight of 20 kg or more, then the effective amount is 35-45 mg, optionally about 40 mg.

3. The method of claim 1 or the use of claim 2, wherein the patient is white.

4. The method or use of any one of claims 1-3, wherein the patient does not have an Asian ethnicity.

5. The method or use of any one of claims 1-4, wherein the compound is administered in the form of a suspension of granules.

6. The method or use of any one of claims 1-5, wherein the compound is orally administered.

7. The method or use of any one of claims 1(ii)(a), 2(ii)(a) and 3-6, wherein the patient is 1 year old or older but younger than 5 years.

8. The method or use of any one of claims 1(ii)(b), 2(ii)(b) and 3-6, wherein the patient is 5 years old or older but younger than 12 years.

22051576_1 (GHMatters) P118017.AU

9. The method or use of any one of claims 1(ii)(b), 2(ii)(b), 3-6 and 8, wherein the patient has a body weight which is less than 40 kg.

10. The method or use of any one of claims 1-9, wherein the patient is healthy except for the influenza virus infection. 22051576_1 (GHMatters) P118017.AU

11. The method or use of any one of claims 1-10, wherein the patient is diagnosed as having 2019461218

an influenza virus infection: (a) due to the presence of fever of 38°C or more (tympanic temperature); and at least one respiratory symptom, optionally cough and/or nasal congestion; and/or (b) by using an influenza test kit.

12. The method or use of any one of claims 1-11, wherein the influenza virus is a type A influenza virus.

13. The method or use of any one of claims 1-12, wherein the compound is administered within 96 hours from the time of symptom onset, optionally within 48 hours from the time of symptom onset.

14. The method or use of claim 13, wherein the symptom onset is the time point of the onset of at least one systemic symptom and/or at least one respiratory symptom.

15. The method or use of claim 14, wherein the at least one systemic symptom is at least one symptom selected from headache, feverishness, chills, muscular pain, joint pain, and fatigue.

16. The method or use of claim 14 or 15, wherein the at least one respiratory symptom is at least one symptom selected from coughing, sore throat, and nasal congestion.

17. The method or use of any one of claims 1-16, wherein the patient to whom the compound has been administered has a decreased virological activity as compared to a patient to whom the compound has not been administered.

18. The method or use of claim 17, wherein the virological activity is measured by: (i) determination of the time to cessation of viral shedding; (ii) determination of the influenza virus titer; and/or (iii) determination the amount of virus RNA.

22051576_1 (GHMatters) P118017.AU

19. The method or use of claim 18(i), wherein the duration of influenza virus shedding is measured as time to shedding cassation following symptom onset.

20. The method or use of claim 18(iii), wherein the amount of virus RNA is measured by using reverse transcriptase-polymerase chain reaction (RT-PCR). 22051576_1 (GHMatters) P118017.AU

21. The method or use of any one of claims 1-20, wherein the compound reduces the time to 2019461218

alleviation of influenza signs and symptoms (TASS) by at least 6 hours, optionally by at least about 12 hours as compared to a patient to whom the compound has not been administered.

22. The method or use of any one of claims 1-21, wherein the time from diagnosis of the influenza virus infection until recovery is decreased in the patient to whom the compound has been administered as compared to a patient to whom the compound has not been administered.

23. The method or use of claim 21 or 22, wherein the patient has recovered when at least one of the following recovery criteria is met and remains met for at least 21.5 hours: (i) return to afebrile state (tympanic temperature ≤ 37.2 °C); (ii) a score of 0 (no problem) or 1 (minor problem) for cough and nasal symptoms as specified in items 14 and 15 of the Canadian Acute Respiratory Illness and Flu Scale (CARIFS), optionally a score of 0 (no problem) or 1 (minor problem) for all 18 symptoms specified in the (CARIFS); (iii) cessation of viral shedding; and/or (iv) return to normal health and activity.

24. The method or use of claim 23(iv), wherein return to normal health and activity is achieved if the patient is able to return to day care or school, and/or to resume his or her normal daily activity in the same way as performed prior to developing the influenza virus infection.

25. The method or use of any one of claims 17-24, wherein the patient to whom the compound has not been administered has been administered oseltamivir.

26. The method or use of any one of claims 1-25, wherein the administration of the compound prevents the occurrence of an influenza-related complication.

22051576_1 (GHMatters) P118017.AU

27. The method or use of claim 26, wherein the influenza-related complication is at least one of 30 Sep 2025

the complications selected from the group consisting of radiologically confirmed pneumonia, bronchitis, sinusitis, otitis media, encephalitis/encephalopathy, febrile seizures, and myositis.

28. The method or use of any one of claims 1-27, wherein death of the patient caused by the 22051576_1 (GHMatters) P118017.AU

influenza virus infection is prevented by the administration of the compound. 2019461218

29. The method or use of any one of claims 1-28, wherein the requirement of antibiotics is prevented by the administration of the compound.

30. The method or use of any one of claims 1-29, wherein the compound has the formula (I).

22051576_1 (GHMatters) P118017.AU

WO wo 2021/028024 PCT/EP2019/071699

1/10

Figure 1: Simulated total drug exposure for three different dosing regimens in pediatrics

(Non-Asian, Age 1-12 year olds)

1 mg/kg < 40 kg, 40 mg flat 40 40kg kg 1.5 mg/kg < 25 kg, 40 mg flat 25 25kg kg 1 1 2 25000 25000 Non-Asian Pediatrics_simulation Non-Asian Pediatrics_simulation o Phase Adult 3 Adult Phase 3 A dult Phase Phase 3_Adult 3_Adult (Asian) (Asian) 8 Phase 3 3 A-dult 8 Phase dult(Asian) (Asian) 20000 20000 20000 Phase 3_Adult (Non-Asian) Phase Phase3_A-dult 3_Adult(Non-Asian) (Non-Asian) XXX XXX Phase Phase3 Pediatrics D Phase Phase 33_Pediatrics Pediatrics (ng.hr/mL) AUC0-inf (ng.hr/mL) AUCD-inf Pediatrics TQT 80 mgmg TQT_80 TQT 80 mg TQT_80mg CIKE> OKD

15000 Phase 10 mg mg 2 10 mean mean 0 15000 Phase 2 10 mg mean mgmean 0 6 6

10000 0 10000 1-0000 0 00 8 GENE

5000 5000

0 00 10 15 20 25 30 35 40 45 50 55 60 10 15 20 25 30 35 40 45 50 55 60 Body Body weight weight (kg) (kg) Body weight (kg)

3 2.0 mg/kg < 20 kg, 40 mg flat 20 20kg kg 3 25000 25000 Non-Asian Pediatrics_simulation Pe diatrics_simulation

Phase Phase 33_Adult Adult Phase 3 Adult (Asian) 3_Adult 8 20000 20000 Phase 3 Adult (Non-Asian) 3_Adult

Phase 3 Pediatrics O (ng.hr/mL) AUCO-inf TQT 80 mgmg TQT_80 15000 Phase Phase 22 10 10 mg mg mean mean - 0 e D

10000 8 0 9

5000 o

0 10 15 20 25 30 35 40 45 50 55 60

Body weight Body weight(kg) (kg) wo 2021/028024 WO PCT/EP2019/071699

2/10

Figure 2: Simulated peak drug exposure for three different dosing regimens in pediatrics (Non-Asian, Age (Non-Asian, Age1-12 year 1-12 olds) year olds)

1 mg/kg < 40 kg, 40 mg flat 40 40kg kg 1.5 mg/kg < 25 kg, 40 mg flat 25 25kg kg 1 500 2 500 Non Asian Pediatrics_simulati Non-Asian on Pediatrics_simulation o Non-Asian Pediatrics_simulation O Phase Adult 3_Adult 3_Adult Phase Adult Phase 3 Adult (Asian) 3_Adult Phase Phase 33_Adult Adult (Asian) (Asian) 400 400 400 3 Adult (Non-Asian) Phase 3_Adult Phase 3 Adult (Non-Asian) 3_Adult XXX Phase 3 Pediatrics Phase 3_Pediatrics Phase 33.Pediatrics Pediatrics ////// TQT_ 80 mg TQT_80 mg

(ng/mL) Cmax TQT 80 mg TQT_80mg (ng/mL) Cmax 1010 Phase 2 mgmg mean mean 300 Phase 2 10 mg 210 mg mean mean 300

000

200 0 200 C docc

B O o

100 100

0 0 10 15 10 15 30 35 20 25 30 35 40 45 50 40 45 50 55 55 60 60 10 15 20 25 30 35 40 45 50 55 60

Body weight (kg) Body weight (kg)

2.0 mg/kg < 20 kg, 40 mg flat 20 20kg kg 500 3 Non-Asian Pediatrics_simulation 0 Phase Adult 3_Adult Phase 3 Adult (Asian) 3_Adult B 400 Phase Phase3 Adult (Non-Asian) 3_Adult(Non-Asian) XXX Phase 3_Pediatics Phase Pediatrics TQT_80mg (ng/mL) Cmax 300 Phase 2 10 mg mean

0 000

200 o 0000

e

100

0 10 15 10 25 30 15 20 25 30 35 35 40 40 45 50 55 45 50 55 60 60

Body weight (kg)

WO wo 2021/028024 PCT/EP2019/071699 PCT/EP2019/071699

3/10

Simulated Figure 3: Simulated drug drug exposure exposure atat 2424 hours hours after after dosing dosing for for three three different different dosing dosing regimens in pediatrics (Non-Asian, Age: 1-12 year olds)

1 1 mg/kg < 40 kg, 40 mg flat 40 40kg kg 1.5 mg/kg < 25 kg, 40 mg flat 25 25kg kg

250 250 2 Non-Asian Pediatrics_sinmlation Pediatrics_simulation Non-Asian Pediatrics_simulation

Phase 3 Adult 3_Adult Phase Adult 3_Adult Phase 3_Adult(Asian) o Phase 3 Adult(Asian) 3_Adult (Asian) 200 200 200 Phase 3 Adult (Non-Asian) 3_Adult(Non-Asian) 3 Adult (Non-Asian) Phase 3_Adult XXX 0 Phase 3 Pediatrics 3_Pediatrics Phase 3 Pediatrics 8 8 C24 (ng/mL) TQT 80 mg TQT_80mg C24 (ng/mL) TQT 80 mg TQT_80mg 150 Phase 210 mg mean 0 0 150 Phase Phase 10 mg mg 2 10 mean mean 0 150 150

B B o 6 8 8 100 100 100 0 of 0 +0 50 50

0 o 0 0 o 15 20 10 15 20 25 25 30 30 35 35 40 404545505055556060 10 15 20 10 15 20 25 25 30 30 35 404545505055556060 35 40

Body weight (kg) Body weight (kg)

2.0 mg/kg < 20 kg, 40 mg flat 20 20kg kg 250 250 3 Non-Asian Non-Asian Pediatrics_simulation Pediatrics_simulation

Phase Phase 33_Adult Adult Phase 3 Adult (Asian) 3_Adult(Asian) o 0 200 200 XXXX Phase Phase 33_Adult Adult (Non-Asian) (Non-Asian) 0 Phase 3 Pediatrics 3_Pediatrics

////// 8 C24 (ng/mL) TQT 80 mg TQT_80 150 Phase 210 mg mean

0 X300

100

*o 50

0 o 10 15 10 15 20 20 25 25 30 30 35 404545505055556060 35 40

Body weight (kg)

WO wo 2021/028024 PCT/EP2019/071699

4/10

Figure Figure 4: 4: Simulated Simulated drug drug exposure exposure at at 72 72 hours hours after after dosing dosing for for three three different different dosing dosing regimens in pediatrics (Non-Asian, Age: 1-12 year olds)

1 1 mg/kg < 40 kg, 40 mg flat 40 40kg kg 2 1.5 mg/kg < 25 kg, 40 mg flat 25 25kg kg

120 120 120 Non-Asian Non-A sianPediatrics_simulation Pediatrics_simulation Non-Asian Non-A sian Pediatrics_simulation Pediatrics_simulation

Phase Phase3 _Adult 3_Adult Phase Phase3 _Adult _Adult 100 100 Phase 3 Adult (Asian) 3_Adult 100 100 Phase 3 Adult (Asian) 3_Adult Phase 3 Adult (Non-Asian) 3_Adult Phase 3 Adult (Non-Asian) 3_Adult Phase 3 Pediatrics Phase Phase 33 Pediatrics Pediatrics 8 0

80 TQT_ 80 mg TQT_80 mg 80 80 TQT_80 mg 0 C72 (ng/mL)

0 0 C72 (ng/mL)

o 0 Phase 2 10 mg mean Phase 2 10 mg mean

60 60 6 8 8 8

40 40 40 O 333 O 3 - 9 9 20 # 20

o a o o 0 0 10 15 15 20 20 25 25 30 30 35 35 40 4045 45505055556060 10 15 20 25 30 35 40 45 50 55 60

Body weig Body ht (kg) weight (kg) Body weight (kg)

2.0 mg/kg < 20 kg, 40 mg flat 20 20kg 3 kg 120 120 Non-A sian Non-A sanPediatrics_simulation Pediatrics simulation Phase Phase 3_Adult 3_Adult 100 Phase 3 Adult (Asian) 3_Adult Phase 3 Adult (Non-Asian) 3_Adult Phase Phase3 Pediatrics _Pediatrics $300 O

80 ////// TQT_80 mg C72 (ng/mL)

Phase Phase 22 10 10 mg mg mean mean O 0

60 6 8

40 40 O THE

# e 0 $ R 9 o a 0 10 15 20 25 30 35 40 45 50 55 60

Body weight (kg)

WO wo 2021/028024 PCT/EP2019/071699

5/10

Figure 5: Simulated total drug exposure for three different dosing regimens in pediatrics (Non-Asian, Age:< 1 (Non-Asian, Age: <1year yearold) old)

1 1.5 mg/kg 1 mg/kg 2 25000 25000

Non-Asian Pediatrics simulation Non-Asian Pediatrics_simulation o Phase 3_Adult Phase 3 Adult 3_Adult 8 8 Phase3 Adult (Asian) Phase3_Adult (Asian) Phase3_Adult (Asian) 20000 Phase3_Adult (Asian) 20000 20000 Phase3_Adult(Non-Asian) Phase3_Adult (Non-Asian) Phase3_Adult (Non-Asian) o

(ng.hr/mL) AUC0-inf 0 (ng.hr/mL) AUC0-inf Phase Pediatrics Phase Pediatrics

TQT 80mg (INCD TQT TQT 80mg 80mg CINCD

15000 15000 Phase Phase 22 10 10 mg mg mean mean O Phase 2 10 mg mean 8 R 6

o D

10000 6 10000 6 com o 0 9 8 the

5000 5000 5000 o o 0000

**

0 0 33 6 9 12 0 3 6 9 12 0

Age (month) Age (month)

2 mg/kg 3 35000 35000 Non-Asian Pediatrics_simulation

30000 Phase Adult 3_Adult 30000 (AMAR Phase3_Adalt Phase3_Adult (Asian) (Asian) Phase3_Adult (Non-Asian) Phase3_Adult (Non-Asian) (ng.hr/mL) AUC0-inf 25000 25000 Phase Pediatrics TQT 80mg TQT 80mg 0 Phase 2 1010 mgmg mean mean 8 20000 20000 o CRD OR 15000

0 10000

5000 5000 :

0 0 3 6 9 12

Age (month)

WO wo 2021/028024 PCT/EP2019/071699

6/10

Figure 6: Simulated peak drug exposure for three different dosing regimens in pediatrics (Non-Asian, Age:< 1 (Non-Asian, Age: <1year yearolds) olds)

1 1 mg/kg 2 1.5 mg/kg 500 500 Non-Asian Pediatrics_simulation Non-Asian Pediatrics_simulation 0 Non-Asian Pediatrics_simulation o Phase Phase 3_Adult 3_Adult Phase 3_Adult Phase Adult Phase3 Adult (Asian) Phase3_Adult Phase3_Adult (Asian) 400 400 Phase3_Adult (Non-Asian) KXXI Phase3_Adult(Non-Asian) Phase3_Adult (Non-Asian) XXX Phase Phase 33 Pediatrics Pediatrics Phase Pediatrics TQT 80mg

(ng/mL) Cmax Cmax (ng/mL) THAN TQT TQT 80mg 80mg Phase 2 10 mg mean 300 Phase 2 10 mg mean 300

000

200 200 o COOD

0 0 O

100 100 100

0 0 0 3 6 9 12 0 3 6 12 12 9 Age (month) Age Age (month) (month)

2 mg/kg 500 3 Non-Asian Pediatrics_simulation O Phase _Adult 3_Adult Phase3_Adult (Asian) Phase3_Adult(Asian) 400 Phase3 Adult (Non-Asian) Phase3_Adult XXX Phase Phase3 Pediatrics Pediatrics Cmax (ng/mL) TQT TQT 80mg 80mg 300 Phase Phase 22 10 10 mg mg mean mean

000

200 200 o 3000

0

100

0 0 3 6 12 9 Age Age (month) (month)

WO wo 2021/028024 PCT/EP2019/071699

7/10

Figure 7: Simulated drug exposure at 24 hours after dosing for three different dosing regimens in pediatrics (Non-Asian, Age: < <11 year year olds) olds)

1 1 mg/kg 1.5 mg/kg 250 250 2 250 Non-Asian Pediatrics_simulation Non-Asian Pediatrics_simulation Pediatrics_sinmalation

Phase Adult 3_Adult Phase 3_Adult Phase3_Adult (Asian) o 0 Phase3_Adult (Asian) 200 200 200 Phase3 Adult (Non-Asian) Phase3_Adult Phase3_Adult(Non-Asian) Phase3_Adult (Non-Asian) XXX Phase Phase Pediatrics Pediatrics Phase Pediatrics 8 8 C24 (ng/mL) TQT 80mg C24 (ng/mL) TQT 80mg 150 Phase 10 mg mean 150 Phase 10 mg mean 0 : 0 CODE

IDO 200 100 100 100 of 0 c 50 50 50

03 CO GO as

0 0 0 0

0 3 6 9 12 0 3 6 9 12

Age (month) Age (month)

2 mg/kg 3 300 300 Non-Asian Pediatrics_simulation

Phase 3 Adult 3_Adult 250 Phase3_Adult (Asian) Phase3_Adult (Non-Asian) XXX Phase 3 Pediatrics Phase Pediatrics O O 200 TQT 80mg C24 (ng/mL)

O Phase 10 Phase 10 mg mg mean mean bood

150 0 0 O COME IDO

100 100

+o 50

Of

0 0 3 6 9 12

Age (mouth) (month)

WO wo 2021/028024 PCT/EP2019/071699

8/10

Figure Figure 8: 8: Simulated Simulated drug drug exposure exposure at at 72 72 hours hours after after dosing dosing for for three three different different dosing dosing regimens in pediatrics (Non-Asian, Age: < <11 year year olds) olds)

1 1 mg/kg 2 1.5 mg/kg

120 120 120 Non-Asian Pediatrics_simulation Non-Asian Pediatrics_simulation

Phase Adult 3_Adult Phase Adult 100 Phase3_Adult (Asian) 100 100 Phase3_Adult (Asian) Phase3_Adult(Asian) Phase3 Adult (Non-Asian) Phase3_Adult(Non-Asiam) Phase3_Adult(Non-Asian) Phase3_Adult (Non-Asian) Phase 3 Pediatrics Phase Pediatrics 00 00 0 Phase Pediatrics 0.00 o

80 TQT 80mg 80 TQT 80mg C72 (ng/mL) O O C72 (ng/mL) o 0 Phase 10 mg mean Phase 10 mg mg 2 10 mean mean

60 B 60 8 8 B

40 40 o 0 III) del

9 g 9 20 20 o 0 O O O o 0 0 0 3 6 9 12 0 3 6 9 12

Age (month) Age (month)

3 2 mg/kg 200 Non Non Asian Asian Pediatrics_simulation Pediatrics_simulation

Phase Phase 3_Adult 3_Adult Phase3_Adult(Asian) Phase3_Adult(Asian) Phase3_Adult (Non-Asian) Phase3_Adult(Non-Asian) 150 XXX Phase 3 Pediatrics Pediatrics Phase

C72 (ng/mL) TQT 80mg 1010 Phase 2 mgmg mean mean

100 100 1000

O 0

6 0 50

0 0 o 0 3 6 9 12

Age (month)

WO wo 2021/028024 PCT/EP2019/071699

9/10

Figure 9.

Canadian Acute Respiratory Illness and Flu Scale (CARIFS) Questionnaire

Item Don't No Minor Moderate Major Know/Not Problem Problem Problem Problem Applicable

1. Poor appetite 2. Not sleeping well

3. Irritable, cranky, fussy

4. Feels unwell 5. Low energy. tired

6. Not playing well

7. Crying more than usual

8. Needing extra care

9. Clinginess

10. Headache 11. Sore throat

12. Muscle aches or pains

13. Fever

14. Cough 15. Nasal congestion, runny nose

16. Vomiting 17. Not interested in what's going on

18. Unable to get out of bed

Since the last assessment has the subject been able to return to day care/school, or resume their normal daily activity in the same way as performed prior to developing the flu? Yes No This form was filled out by: Parent

Carer

Other

Note: The term "Carer" in this questionnaire corresponds to the term "caregiver" used throughout the protocol.

Figure 10.

Powder X-ray diffraction pattern of the crystal of compound I

40. 001 100

30. 000 000 00

30,

26 (° (°)

20. 000 000

10. 000

C p S (cps)

80000 00000 60000 00000 40000 20000