HK1110531A - Methods for administering dpd inhibitors in combination with 5-fu and 5-fu prodrugs - Google Patents

Description

Methods of administering DPD inhibitors in combination with 5-FU and 5-FU prodrugs

Background

Technical Field

The present invention relates generally to cancer therapy, and more particularly to cancer therapy using DPD inhibitors in combination with 5-FU and/or 5-FU prodrugs.

Description of the Related Art

5-Fluorouracil (5-FU) has been used clinically to treat solid tumors in cancer patients for more than 30 years (Ansfield et al, Cancer 39: 34-40, 1977; grem et al, Cancer Treat Rep 71: 1249-1264, 1987; chabner et al, Cancer, Principles and Practice of Oncology, 2^ndEd, pp 287-328Philadelphia, PA: j B Lippincott Co, 1985). 5-FU must be activated by metabolic conversion to pseudo-uridine nucleotides (e.g., FUMP, FUDP, FUTP) and pseudo-deoxyuridine nucleotides (e.g., FdUMP, FdUDP, FdUTP) which can interfere with DNA synthesis and RNA function (see Meyers, Pharmacol Rev, 33: 1-15, 1981; Dasher et al, Pharmac Ther 48: 189-. Since 5-FU differs from its natural counterpart uracil only by a fluorine substitution at position 5, it can be readily activated in cancer patients. Unfortunately, its structural similarity to uracil also results in its rapid and extensive conversion to degradation products that lack anti-tumor activity. The metabolic process is called inactivation. 5-FU is rapidly inactivated by the enzyme dihydropyrimidine dehydrogenase (DPD: EC 1312, uracil reductase) (Meyers, Pharmacol Rev, 33: 1-15, 1981; Dasher et al, PharmacTher 48: 189-222, 1990). Thus, the antitumor efficacy of 5-FU for the treatment of cancer depends on a delicate balance between metabolic conversion to antitumor nucleotides (activation) and metabolic conversion to unwanted metabolites (inactivation).

In addition, several clinical problems arise due to metabolic inactivation of 5-FU. First, because DPD levels vary between individuals (Fleming et al, Cancer Res 52: 2899-. In extreme cases, DPD genetic-deficient patients experience severe and sometimes fatal toxicity when treated with 'standard' therapeutic doses of 5-FU (for review see Morrison et al, Oncol Nurs Forum 24: 83-88, 1997). Second, variable levels of DPD in the gastrointestinal tract (Ho et al, Anticancer Res 6: 781-784, 1986; Naguib et al, Cancer Res 45: 5405-5412, 1985; Spector et al, Biochem Pharmacol 46: 2243-. Third, tumors containing high levels of DPD are less likely to respond to 5-FU treatment (Etienne et al, J Clin Oncol 13: 1663-. Finally, degradation products of 5-FU may produce neurotoxicity (Okeda et al, Acta neuropathohol 81: 66-73, 1990; Koenig et al, Arch Neurol 23: 155-.

DPD is a ubiquitous enzyme that is the 1 st and rate-limiting step in the degradation (inactivation) of 5-FU. Studies have shown that inhibition of DPD prolongs the half-life of 5-FU in plasma. Several inhibitors of DPD have been studied, including inhibitors that irreversibly inactivate DPD, as well as inhibitors that reversibly inhibit DPD.

5-ethynyluracil, also known as eniluracil, is an example of a DPD inhibitor, which is an irreversible inactivator of DPD that reduces or eliminates The metabolic inactivation of 5-FU (reviewed in Spector et al, Drugs of The Future 19: 565-. With the structural similarity between eniluracil and 5-FU, eniluracil is a substrate of DPD. As DPD attempts to degrade eniluracil, the latter is converted to a highly reactive compound which binds irreversibly to DPD and thus inactivates the enzyme. Thus, in the presence of very low amounts of eniluracil, the DPD is destroyed and is no longer able to inactivate the 5-FU. Active DPD is only re-emerged in the patient due to de novo DPD enzyme synthesis over a period of several days.

Enuracil has been tested in phase I clinical trials in cancer patients (reviewed in Levin et al, Invest New Drugs 18: 383-90, 2000; Baker et al, J Clin Oncol 18: 915-9262000; Schilsky et al, J Clin Oncol 4: 1450-7, 1998). It is very effective in eliminating DPD activity without causing toxicity. 0.74mg/m²The dose of (total about 1mg) eliminated more than 90% of all DPD over a long period of time. In fact, the level of DPD is only 3% of the pre-dose level 24 hours after one dose of eniluracil. The elimination half-life of 5-FU was increased from about 10 minutes to 3.5 hours by administering one dose of eniluracil. The dosage is 3.7mg/m²The eniluracil of (a) extends the half-life of 5-FU to 4.5 hours. Higher doses do not add significant benefit.

Eniluracil has also been administered orally in phase II and III clinical trials (reviewed in Levin et al, Invest New Drugs 18: 383-90, 2000; Schilsky et al, J ClinOncol: 20: 1519-26, 2002). Two dosing regimens were used in the above experiments. In the '5-day regimen', eniluracil is administered at a fixed dose of 50mg per day, on days 1 to 7. 5-FU is at about 20mg/m²On days 2 to 6 following eniluracil administration. In the '28-day protocol', eniluracil and 5-FU are in a 10: 1 eniluracil: fixed ratio co-administration of 5-FU b.i.d. (2 times 1 day) for 28 days. The dose of 5-FU is about 1mg/m². Eniluracil eliminates the 5-FU-associated hand-foot syndrome toxicity, enabling 5-FU to be administered orally safely, and producing highly predictable plasma levels of 5-FU. Unfortunately, however, the antitumor activity of the protocol is disappointing. In two multicenter phase III studies using a 28-day eniluracil regimen for colorectal cancer treatment, patients receiving eniluracil and 5-FU tended to have lower antitumor activity than patients treated with the standard 5-FU regimen without eniluracil (Schilsky et al, J Clin Oncol：20：1519-26，2002)。

Thus, there remains an important and unmet need in the art to identify optimal dosing and administration regimens for the use of DPD inhibitors in combination with 5-FU and 5-FU prodrugs in order to maximize the antitumor efficacy and therapeutic index of the 5-FU and 5-FU prodrugs, to improve the predictability of dosing, and to enable the 5-FU and 5-FU prodrugs to be effectively administered orally. The present invention fulfills these needs and provides other related advantages.

Summary of The Invention

The present invention relates generally to improved methods of administering DPD inhibitors such as eniluracil in combination with 5-FU and a 5-FU prodrug. Thus, according to one aspect of the present invention there is provided a method of treating cancer in a patient comprising first administering a DPD inhibitor which substantially eliminates this enzyme and then administering 5-FU or a 5-FU prodrug, wherein the 5-FU or 5-FU prodrug is administered at a dose such that: upon its administration, the 5-FU or 5-FU prodrug is present in the patient in an amount significantly exceeding the free DPD inhibitor.

In one embodiment according to this aspect of the invention, the 5-FU or 5-FU prodrug is administered at least about 4 hours, at least about 6 hours, at least about 8 hours, at least about 10 hours, at least about 12 hours, at least about 14 hours, at least about 24 hours, or at least about 36 hours after the DPD inhibitor is administered.

In another embodiment according to this aspect of the invention, the 5-FU or 5-FU prodrug is administered about 4-72 hours, 4-36 hours, 4-24 hours, 4-14 hours, 6-14 hours, or 8-14 hours after the DPD inhibitor is administered.

In another embodiment according to this aspect of the invention, the 5-FU or 5-FU prodrug is administered at a time that: at least about 0.1-4 elimination half-lives, 1-4 elimination half-lives, 2-4 elimination half-lives, or 3-4 elimination half-lives of the DPD inhibitor have passed since the administration of the DPD inhibitor.

In another embodiment according to this aspect of the invention, the DPD inhibitor is administered at a dose sufficient to reduce DPD activity in the patient to less than about 10%, less than about 5%, less than about 3% or less than about 1% of baseline DPD activity in the patient.

In another embodiment according to this aspect of the invention, the 5-FU or 5-FU prodrug is administered at a dose that is: upon its administration, the 5-FU or 5-FU prodrug is present in the patient in an amount at least about 2-fold, at least about 3-fold, at least about 5-fold, or at least about 100-fold more than the DPD inhibitor.

In another embodiment according to this aspect of the invention, the DPD inhibitor is an irreversible DPD inhibitor.

In another embodiment according to this aspect of the invention, the DPD inhibitor is a reversible DPD inhibitor. In such embodiments, it will be appreciated that certain preferred reversible DPD inhibitors include tightly bound inhibitors which dissociate from DPD at a slower rate than excess inhibitor is eliminated from the body and therefore are not present in significant excess when 5-FU or the 5-FU prodrug is administered. Other preferred inhibitors include inhibitors that inhibit DPD activity but do not significantly inhibit other enzymes that activate fluorouracil, such as uridine phosphorylase (upese), orotate phosphoribosyltransferase (OPRTase) and Thymidine Phosphorylase (TP).

In another embodiment according to this aspect of the invention, the 5-FU or 5-FU prodrug is selected from the group consisting of the following compounds and their 5' -esters, including phosphate esters: 5-fluorouridine, 5-fluorocytidine, 5-fluoro-2-deoxyuridine, 5-fluoro-2-deoxycytidine, and 5-fluorouracil.

In another embodiment according to this aspect of the invention, the 5-FU or 5-FU prodrug is selected from the group consisting of: 5 ' -deoxy-4 ', 5-fluorouridine, 5 ' -deoxy-5-fluorouridine, 1- (2-tetrahydrofuryl) -5-fluorouracil，1-C_1-8Alkylcarbamoyl-5-fluorouracil derivatives, 1- (2-tetrahydrofuryl) -5-fluorouracil, 5' -deoxy-5-fluoro-N- [ (pentyloxy) carbonyl]-cytidine (capecitabine), or a compound capable of being converted in vivo into 5-FU.

In another embodiment according to this aspect of the invention, the DPD inhibitor is eniluracil or a prodrug thereof.

In another embodiment according to this aspect of the invention, the DPD inhibitor is eniluracil and is administered at a dose of 0.8-15, 2-15, 5-15 or 2.5-5mg/m²。

In another embodiment according to this aspect of the invention, the DPD inhibitor is eniluracil and the 5-FU or 5-FU prodrug is 5-FU.

In another embodiment according to this aspect of the invention, the 5-FU or 5-FU prodrug is 5-FU and is administered in a dose of 0.5-80, 0.5-40, 10-80, 10-60, 10-30 or 20-60mg/m²。

In another embodiment of the invention, the dosage ratio of eniluracil to 5-FU or a 5-FU prodrug is from 1: 3 to 1: 20, from 1: 5 to 1: 15, or from 1: 8 to 1: 12.

In a preferred embodiment, the amount of the first component is about 2.5-5mg/m²The dosage of eniluracil is about 15-30mg/m at least about 10-14 hours later²Or a 5-FU or 5-FU prodrug or administered in a dose of about 5-100mg/m²Capecitabine of (1). Alternatively, additional doses of 5-FU or capecitabine may be administered thereafter, with or without additional doses of eniluracil.

In another embodiment according to this aspect of the invention, the DPD inhibitor is eniluracil and the 5-FU or 5-FU prodrug is capecitabine.

In another embodiment according to this aspect of the invention, the DPD inhibitor is eniluracil, the 5-FU or 5-FU prodrug is 5-FU or capecitabine, and the eniluracil is administered at a dose of about 08-15, 2.5-15, 5-15 or 2.5-5mg/m²。

In another embodiment according to this aspect of the invention, the DPD inhibitor is eniluracil, the 5-FU or 5-FU prodrug is 5-FU, and the eniluracil is administered at a dose of about 2.5-5mg/m²And said 5-FU is administered in a dose of about 0.5-40mg/m²Depending on the dosage regimen used.

An exemplary regimen, e.g., a 1 day 2 times (b.i.d.) 28 day (28-day) regimen, employs 5-FU in a dose of about 0.5-1.5mg/m². Another exemplary regimen, e.g., a 1-day 1-time for 5-day (5-day) regimen, employs 5-FU in a dose of about 10-60mg/m². In a more specific embodiment, the dose of 5-FU is from about 10 to about 30mg/m². In another embodiment, the dose of 5-FU is from about 20 to about 60mg/m²。

In another exemplary embodiment, e.g., a 1 week 1 (weekly) regimen, 5-FU may be administered in a dose of about 10-80mg/m². In more specific embodiments, 5-FU is administered in a dose of about 15-40 or 10-30mg/m². In another embodiment, 5-FU is administered in a dose of about 30-80mg/m²。

In another embodiment according to this aspect of the invention, the DPD inhibitor is eniluracil, the 5-FU or 5-FU prodrug is capecitabine, and the eniluracil is administered at a dose of about 0.8-15, about 2-15, about 5-15, or about 2.5-5mg/m²The capecitabine is administered in a dosage of about 0.8-200mg/m². In a more specific embodiment, the capecitabine is administered in a dose of about 0.8-10mg/m²Or 1.3-4mg/m²(e.g., for certain exemplary extended daily regimens of 2 times a day for 1 day).

In another embodiment according to this aspect of the invention, the DPD inhibitor comprises a 5-substituted uracil analog or a prodrug thereof.

In another embodiment according to this aspect of the invention, the DPD suppression is performed by a single processorThe agents include uracil analogs substituted at the 5-position with: a halogen atom, C_2-4Alkenyl, C substituted by halogen_2-4Alkenyl radical, C_2-6Alkynyl, C substituted by halogen_2-6Alkynyl, cyano or C substituted by halogen_1-4An alkyl group.

In another embodiment according to this aspect of the invention, the DPD inhibitor comprises a uracil analogue selected from the group consisting of: eniluracil, 5-propynyluracil, 5-cyanouracil, 5-propynyluracil, 5-bromoethynyluracil, 5- (1-chloroethenyl) uracil, 5-iodouracil, 5-bromovinyluracil, (E) -5- (2-bromovinyl) uracil, 5-hex-1-ynyluracil, 5-vinyluracil, 5-trifluorouracil, 5-bromouracil, and 5- (2-bromo-1-chloroethenyl) uracil.

In another embodiment according to this aspect of the invention, the DPD inhibitor is selected from the group consisting of: 5- (phenylselenenyl) uracil (PSU), 5- (phenylthio) uracil (PTU), 5- (phenylseleno) barbituric acid and 5- (phenylthio) barbituric acid.

According to another aspect of the present invention there is provided a method of treating cancer in a patient comprising administering first eniluracil and then 5-FU, wherein the 5-FU is administered at a dose such that: upon its administration, the 5-FU is present in the patient in an amount significantly exceeding that of the DPD inhibitor.

In one embodiment according to this aspect of the invention, the 5-FU is administered at least about 4 hours, 6 hours, 8 hours, 10 hours, 12 hours, 14 hours, 24 hours, or 36 hours after the eniluracil is administered. In a preferred embodiment, the 5-FU is administered at least about 4 hours, at least about 8 hours, or at least about 12 hours after the eniluracil is administered.

In another embodiment according to this aspect of the invention, the 5-FU is administered about 4-72 hours, 4-36 hours, 4-24 hours, 4-14 hours, 6-14 hours, or 8-14 hours after the eniluracil is administered. In a preferred embodiment, the 5-FU is administered about 4 to 14 hours after the eniluracil is administered.

In another embodiment of the invention, the 5-FU is administered at a time such that: since the administration of eniluracil, about 0.1 to 4 elimination half-lives, 1 to 4 elimination half-lives, 2 to 4 elimination half-lives or 3 to 4 elimination half-lives of eniluracil have been passed.

In another embodiment according to this aspect of the invention, the eniluracil is administered in an amount sufficient to reduce DPD activity in the patient to less than about 10%, less than about 5%, less than about 3% or less than about 1% of baseline DPD activity.

In another embodiment according to this aspect of the invention, the 5-FU is administered at a dose that: upon administration thereof, the 5-FU is present in the patient in an amount at least about 2-fold, at least about 3-fold, at least about 5-fold, or at least about 100-fold greater than the eniluracil.

In another embodiment according to this aspect of the invention, the eniluracil is administered in an amount of about 0.7-15mg/m². In another embodiment of the invention, the eniluracil is administered in an amount of about 2.5-5mg/m². In another embodiment of the invention, the eniluracil is administered in an amount of about 5-15mg/m²。

In another embodiment according to this aspect of the invention, the eniluracil is administered in an amount of about 2.5-5mg/m²And said 5-FU is administered in a dose of about 0.5-40mg/m²。

According to another aspect of the present invention, there is provided a method of treating cancer in a patient comprising administering first eniluracil and then 5-FU, wherein said eniluracil is administered at a dose of about 2.5-5mg/m²And wherein the time of administration of said 5-FU is such that: from the time of eniluracil administration, elimination half-lives of approximately 1-4, 2-4, or 3-4 eniluracils have passed.

In one embodiment according to this aspect of the invention, the 5-FU is administered at least about 4 hours, 6 hours, 8 hours, 10 hours, 12 hours, or 14 hours after the eniluracil is administered.

In one embodiment according to this aspect of the invention, the 5-FU is administered about 4-36 hours, 4-24 hours, 4-14 hours, 6-14 hours, or 8-14 hours after the eniluracil is administered.

In another embodiment according to this aspect of the invention, the 5-FU is administered at a dose that: upon administration thereof, the 5-FU is present in the patient in an amount at least about 2-fold, at least about 3-fold, at least about 5-fold, or at least about 100-fold greater than the eniluracil.

In another embodiment according to this aspect of the invention, the 5-FU is administered in a dose of about 0.5-40mg/m²。

In a more specific embodiment, eniluracil (or another DPD inhibitor) is administered first, followed by multiple doses of 5-FU or 5-FU prodrug at desired time points, and then optionally followed by another administration of eniluracil (or another DPD inhibitor). For example, in a preferred embodiment, about 2.5-5mg/m is administered first²Is administered at least about 10-14 hours later, e.g., about 15-30mg/m²Or about 5-100mg/m²The evening before day 1 of capecitabine of (a) was administered eniluracil as described above, followed by similar multiple doses of 5-FU or capecitabine. For example, in one illustrative embodiment, eniluracil is administered first, followed by multiple doses of 5-FU or capecitabine per day, e.g., for a three day period per week, followed by optionally administering eniluracil again, and the cycle is repeated.

According to another aspect of the present invention, there is provided a method of treating cancer in a patient comprising administering first eniluracil and then 5-FU, wherein said eniluracil is administered at a dose of about 2.5-5mg/m²When said 5-FU is administeredThe following are the following: from the time of the eniluracil administration, 1-4, 2-4 or 3-4 elimination half-lives of the eniluracil have been passed, and the 5-FU is administered at a dose of about 0.5-40mg/m²。

According to another aspect of the present invention there is provided an oral pharmaceutical time-release (time-release) formulation comprising a DPD inhibitor and 5-FU or a 5-FU prodrug, wherein upon administration of the formulation to a patient, the 5-FU or 5-FU prodrug is not substantially released until about 0.5-36, 4-36, 4-24 or 4-14 hours after the DPD inhibitor has been released.

According to another aspect of the present invention, there is provided a pharmaceutical formulation comprising a DPD inhibitor and a delivery vehicle for administering the DPD inhibitor to a patient. In another embodiment, the formulation comprises a DPD inhibitor and 5-FU or a 5-FU prodrug. In another embodiment, the formulation comprises a delivery vehicle, a DPD inhibitor and 5-FU or a 5-FU prodrug. In a specific embodiment, the delivery vehicle is a microsphere. In related embodiments, the delivery vehicle is a microsphere that is capable of preferentially or selectively targeting the DPD inhibitor to cancer cells using formulation and delivery techniques well known in the art.

The above and other aspects of the invention will be apparent by reference to the following detailed description and attached drawings. Patents and other documents cited herein are incorporated herein by reference in their entirety for the purpose of describing various aspects of the present invention in more detail.

Brief description of the drawings

FIG. 1 shows the chemical structures of eniluracil and 5-FU.

Figure 2 shows that eniluracil results in increased plasma uridine levels after administration in mice.

FIG. 3 shows an exemplary oral extended release formulation comprising eniluracil and 5-FU in the form of a tablet.

Detailed description of the invention

As noted above, the present invention relates generally to methods of treating cancer comprising administering to a patient at least one DPD inhibitor in combination with at least one 5-FU or 5-FU prodrug, and to compositions and formulations useful in such methods. Thus, the methods disclosed herein can be applied to the treatment of essentially any type of cancer in which 5-FU and/or 5-FU precursor is active, including (by way of example but not limitation) breast cancer, lung cancer, colon cancer, pancreatic cancer, gastric cancer, bladder cancer, kidney cancer, head and neck cancer, esophageal cancer, hepatocellular carcinoma, and all malignant leukemias and lymphomas. In addition, because the present invention improves the antitumor efficacy of 5-FU and 5-FU prodrugs, types of cancer that previously may exhibit less than ideal reactivity with 5-FU may exhibit improved reactivity when administered according to the methods disclosed herein.

It has been surprisingly found that DPD inhibitors such as eniluracil are capable of inhibiting the metabolic activation of 5-FU and 5-FU prodrugs and thus impairing their anti-tumor activity. Thus, according to a general aspect of the present invention, by ensuring that the level of 5-FU or 5-FU prodrug substantially exceeds the level of DPD inhibitor when administering 5-FU or 5-FU prodrug to a patient, it is advantageous to minimize the extent to which the DPD inhibitor may interfere with the metabolic activation of the 5-FU or 5-FU prodrug and thus improve the anti-tumour efficacy of these agents. Thus, in certain embodiments, an irreversible DPD inhibitor such as eniluracil should be administered at the lowest dose effective to inactivate DPD, and should preferably be for a sufficient period of time to clear excess inhibitor from the bloodstream prior to administration of 5-FU. In addition, since DPD can be effectively significantly eliminated from the patient's body prior to administration of 5-FU or 5-FU prodrug, the dose of 5-FU or 5-FU prodrug required to obtain the desired level of therapeutic activity can be significantly reduced, thereby providing economic advantages in addition to the therapeutic advantages described herein.

It will be appreciated by those skilled in the art, after reading the present specification, that a variety of administration and dosing regimens are useful in the methods disclosed herein, while ensuring that the level of 5-FU or 5-FU prodrug is a therapeutically effective amount at the time of its administration and sufficiently above the DPD inhibitor level in the patient so as to minimize or eliminate the inhibitory effect on the metabolic activation of 5-FU. All such administration and dosing regimens are considered to be within the scope of the present invention.

In an illustrative embodiment of the invention, a DPD inhibitor is first administered (i.e., predosed) to a patient in need thereof, so as to substantially eliminate DPD activity in the patient, and then 5-FU or a 5-FU prodrug is administered. By "substantially abolished" is meant that the level of DPD activity in the patient is reduced to at least 20%, less than 10%, less than 5%, less than 3% or less than 1% of the baseline level of DPD activity in the patient prior to administration of the DPD inhibitor. The baseline level of DPD activity in a patient can be conveniently determined, for example, by using known techniques in PBMCs from the patient (e.g., Baker et al, J Clin Oncol 18: 915-.

After first administering at least one DPD inhibitor and thus substantially eliminating DPD in a patient, then after sufficient time has elapsed so that the DPD inhibitor can be substantially eliminated from the patient by elimination, administering 5-FU or a 5-FU prodrug, or a combination thereof, to the patient. The time delay between administration of the DPD inhibitor and the 5-FU or 5-FU prodrug can vary, provided that when the 5-FU or 5-FU prodrug is administered, it is present in the patient in a significant excess relative to the level of DPD inhibitor remaining in the patient at that time. In one illustrative embodiment, the 5-FU or 5-FU prodrug is administered at a dose that is: the level of 5-FU or 5-FU prodrug present in the patient is at least a molar excess over the level of DPD inhibitor remaining in the patient, e.g., at least about a 2-fold, at least about a 3-fold, at least about a 5-fold or at least about a 100-fold excess relative to the level of DPD inhibitor remaining in the patient when the 5-FU or 5-FU prodrug is administered. It will be appreciated by those skilled in the art that any of a variety of known and available techniques may be used to calculate and/or determine the level of excess of 5-FU or 5-FU prodrug relative to DPD inhibitor in a patient, in accordance with embodiments disclosed herein. For example, the techniques may include HPLC, LC-MS, ELISA, and other methods. As described above, it is believed that by ensuring that the 5-FU or 5-FU prodrug is present in an amount sufficiently excess relative to the level of DPD inhibitor in the patient at the time of administration of the 5-FU or 5-FU prodrug, interference of the DPD inhibitor with the metabolic activation of the 5-FU or 5-FU prodrug can therefore be minimised, and hence the efficacy of the 5-FU or 5-FU prodrug improved.

In another embodiment of the invention, the 5-FU or 5-FU prodrug is administered to the patient only after at least 0.1-4 elimination half-lives of the DPD inhibitor, 1-4 elimination half-lives, 2-4 elimination half-lives, or 3-4 elimination half-lives have elapsed since the DPD inhibitor was administered. The elimination half-lives of certain DPD inhibitors have been determined and for yet undetermined inhibitors can be conveniently determined using well-known and established gas chromatography/mass spectrometry and HPLC techniques (see Baker et al, J Clin Oncol 18: 915 9262000; Schilsky et al, J Clin Oncol 4: 1450-7, 1998). The elimination half-life of eniluracil in humans is reported to be about 3.5 hours (e.g., Baker et al, J Clin Oncol 18: 915-. Thus, for certain embodiments of the present invention in which eniluracil is used as the DPD inhibitor, in order to allow the levels of eniluracil to be substantially reduced by elimination prior to administration of 5-FU or a 5-FU prodrug, the 5-FU or 5-FU prodrug is administered at least about 0.5 hour, about 2 hours, about 4 hours, about 6 hours, about 8 hours, about 10 hours, about 12 hours, about 14 hours, about 24 hours, or about 36 hours after the eniluracil is administered. In certain other embodiments, the 5-FU or 5-FU prodrug is administered about 4-72 hours, 4-36 hours, about 4-24 hours, about 4-14 hours, about 6-14 hours, or about 8-14 hours after the eniluracil is administered. It will be understood, of course, that the above ranges are illustrative in nature and may be varied as necessary or desired for a particular regimen, so long as the presence of eniluracil is minimized or absent upon administration of 5-FU.

The DPD inhibitor for use in the present invention may be a reversible or irreversible inhibitor of DPD enzyme. Illustrative examples of reversible inhibitors of DPD enzyme include uracil, CDHP, and 3-cyano-2, 6-dihydroxypyridine (CNDP). Other exemplary reversible DPD inhibitors include those disclosed in U.S. patent No. 5,476,855 and WO 95/012400, the contents of which are incorporated herein by reference in their entirety, e.g., 5- (phenylseleno) uracil (PSU), 5- (phenylthio) uracil (PTU), 5- (phenylseleno) barbituric acid, and 5- (phenylthio) barbituric acid. It will be appreciated that certain preferred reversible inhibitors of DPD include tightly bound inhibitors which dissociate from DPD at a slower rate than excess inhibitor is eliminated from the body; and/or inhibitors of other enzymes that inhibit DPD activity but do not significantly inhibit the activation of fluorouracil, such as uridine phosphorylase (upese), orotate phosphoribosyltransferase (OPRTase) and Thymidine Phosphorylase (TP).

In certain preferred embodiments of the invention, the DPD inhibitor is an inhibitor that irreversibly inactivates DPD enzyme. Exemplary DPD inhibitors in this regard include, but are not limited to, DPD inhibitors comprising a 5-substituted uracil compound, or prodrugs thereof, particularly uracil compounds substituted at the 5-position with: a halogen atom, C2-4 alkenyl (e.g., vinyl) group optionally substituted with halogen (e.g., 2-bromovinyl, 1-chloroethenyl or 2-bromo-1-chloroethenyl), C optionally substituted with a halogen atom_2-6Alkynyl, cyano, or C substituted by halogen_1-4Alkyl (e.g., trifluoromethyl).

In more specific embodiments of the invention, the DPD inhibitor is selected from the group consisting of: eniluracil, 5-propynyluracil, 5-cyanouracil, 5-propynyluracil, 5-bromoethynyluracil, 5- (1-chloroethenyl) uracil, 5-iodouracil, 5-bromovinyluracil, (E) -5- (2-bromovinyl) uracil, 5-hex-1-ynyluracil, 5-vinyluracil, 5-trifluorouracil, 5-bromouracil, and 5- (2-bromo-1-chloroethenyl) uracil, or a prodrug thereof.

In another embodiment, the DPD inhibitor is a prodrug of 5-bromovinyluracil, an exemplary compound is represented by the compound 1- β -D-arabinofuranosyl- (E) -5- (2-bromovinyl) uracil (also known as BV-araU or solivudine). Certain exemplary prodrug compounds of this aspect are described, for example, in U.S. patent No. 4,386,076, the contents of which are incorporated herein by reference.

In a preferred embodiment of the invention, the DPD inhibitor is eniluracil or a prodrug of eniluracil, such as 5-ethynyl-2 (1H) -pyrimidinone (eniluracil lacking the 4-oxygen) (Porter, et al, biochem. Pharmacol 47: 1165-seco 1171, 1994), a nucleoside or deoxynucleoside derivative of eniluracil, a compound capable of being converted in vivo to eniluracil, and/or a DPD inactivator derivative capable of being converted in vivo to an inactivator. For example, the compound may include nucleoside derivatives containing a nucleobase corresponding to the 5-substituted uracil compounds described above, e.g., nucleoside derivatives comprising ribose, 2 '-deoxyribose, 2', 3 '-dideoxyribose, arabinose, or other cleavable sugar moieties, which may additionally comprise 2' -or 3 '-substituents such as halogen or 5' -substituents such as esters. More specific examples of the nucleoside derivatives include 1- (. beta. -D-arabinofuranosyl) -5-prop-1-ynyluracil and 2 ', 3 ' -dideoxy-5-ethynyl-3 ' -fluorouridine.

Numerous 5-FU prodrugs are known to be useful in the present invention. Prodrugs of 5-FU are compounds capable of being metabolized to 5-fluorouracil in vivo and may include, for example, 5-fluorouridine, 5-fluorocytidine, 5-fluoro-2-deoxyuridine, 5-fluoro-2-deoxycytidine, 5-fluoroarabinouracil, and their 5' -esters, including phosphate esters. Other exemplary compounds include 5 ' -deoxy-4 ', 5-fluorouridine, 5 ' -deoxy-5-fluorouridine, 1- (2-tetrahydrofuryl) -5-fluorouracil, 1-C_1-8Alkylcarbamoyl-5-fluorouracil derivatives, 1- (2-tetrahydrofuryl) -5-fluorouracil, furacil (tegafur, an oral 5-FU prodrug, which is widely used in Asian countries), and 5' -deoxy-5-fluoro-N- [ (pentyloxy) carbonyl]Cytidine (capecitabine, sold as Xeloda  by roche laboratories inc.), or a compound that can be converted in vivo into 5-FU.

In a particularly preferred embodiment of the invention, the methods disclosed herein employ eniluracil in combination with 5-FU. As indicated above, to maximize the antitumor activity of 5-FU, the eniluracil is administered at a dose that substantially eliminates DPD activity in the patient while also ensuring that the eniluracil is not excessively present when the 5-FU is administered. Since eniluracil is a very potent irreversible inactivator of DPD, it is preferably administered before 5-FU. Eniluracil rapidly inactivates DPD and is then preferably given time to substantially clear the patient by elimination prior to administration of 5-FU. Thus, upon administration of 5-FU to a patient, DPD activity will be substantially eliminated and the level of eniluracil advantageously lower.

As will be appreciated from the present specification, the methods of the invention may also include a regimen of administration of any desired duration and dosing characteristics, provided that the dosing regimen is appropriately selected so that the 5-FU or 5-FU prodrug is present in an amount in excess of the level of eniluracil remaining in the patient's body at the time of administration of the 5-FU or 5-FU prodrug. In an illustrative embodiment employing a particular combination of eniluracil and 5-FU, the methods of the invention comprise a 1 day 1 for a 5 day (5-day) regimen or a weekly (weekly) regimen. For a 5-day or weekly regimen, the dosage of eniluracil will generally range from about 0.8 to 10mg/m²Preferably about 2.5-5mg/m². Note that even higher doses of eniluracil may be used, provided sufficient time has passed to clear excess prior to administration of 5-FU.

For convenience, in certain embodiments, a simple fixed dose of eniluracil is preferred. As disclosed herein, a fixed dose in the range of about 2.5-15mg is generally suitableThe composition is suitable for most patients. In certain preferred embodiments, the fixed dose range is about 2.5-5 mg. Exemplary fixed doses of eniluracil will eliminate DPD in patients of different sizes for more than 24 hours, and in some cases for more than 3-5 days, as shown in the table below.

Body surface area	Dosage of eniluracil	mg/m2
			(Square meter)	(mg)	(scope)
0.5-1.0	2.5	2.5-5.0
			＞1.0-2.0	5.0	2.5-5.0
＞2.0-4.0	10.0	2.5-5.0

In an illustrative embodiment, the time delay between the administration of eniluracil and the administration of 5-FU is about 4-72 hours, 4-36 hours, 4-24 hours, or 4-14 hours (or at least about 1-4 elimination half-lives of eniluracil). For example, eniluracil may be administered in the evening before 5-FU is administered, or may be administered in the morningMorning administration followed by 5-FU in the evening. For example, about 20-30mg/m is used for these protocols²Exemplary doses of 5-FU (Levin et al, Invest New Drugs 18: 383-90, 2000; Schilsky et al, J Clin Oncol 4: 1450-7, 1998; Guo et al, Cancer ChemotherPharmacol 52: 79-85, 2003), 5-FU should always be in a significant excess relative to eniluracil.

In another embodiment, an extended dosing regimen, e.g., a 28-day dosing regimen, may be used. An exemplary 28-day 1-day 2 regimen (e.g., twice daily for 28 days) involves dosing at about 0.5-2mg/m²Preferably about 1mg/m²5-FU (e.g., Baker et al, J Clin Oncol 18: 915-9262000) was administered. To ensure that the eniluracil is present in an amount not exceeding the low 5-FU dose, it may be administered at about 2.5-5mg/m prior to the start of the 1 day 2 regimen²Eniluracil is administered for at least about 12 hours, e.g., in the evening prior to the first day of administration of 5-FU. It may then precede the first 5-FU dose by about 2-8 hours, preferably about 4-6 hours, per day, at about 0.5-2mg/m²For example 1mg/m²A single daily dose of eniluracil was administered for 28 days. This strategy ensures that the level of 5-FU from the first dose substantially exceeds eniluracil, and the level of 5-FU from the second daily dose of 5-FU substantially exceeds eniluracil. During subsequent treatment days, e.g., days 2-28, the patient's blood levels of eniluracil (e.g., when at 1 mg/m)²When administered) should be reduced by about 50% (to 0.5 mg/m) within four hours (first daily dose of 5-FU)²) And a decrease of about 94% (to 0.06 mg/m) by the second 5-FU dose of the day²). Initial 2.5-5mg/m of eniluracil²And subsequent dose of 1mg/m²The dose of (a) is applied to effectively eliminate DPD activity in the patient for 28 days of 5-FU administration.

In another illustrative embodiment, eniluracil (or another DPD inhibitor) is administered first, followed by multiple doses of 5-FU or 5-FU prodrug at desired time points, and then optionally followed by another administration of eniluracil. For example, in an illustrative embodiment, eniluracil is administered first, then multiple doses of 5-FU are administered at exemplary time points about 12 hours, 36 hours, or even 54 hours thereafter, and then optionally eniluracil is administered again, if desired, and the cycle is repeated.

In particular embodiments, the eniluracil and 5-FU are present in a dose ratio of about 1: 5 to 1: 15 or 1: 8 to 1: 12.

In another embodiment of the invention, 5-FU is administered relatively rapidly, e.g., 0-.5-1 hour, after the eniluracil is administered, provided, according to the invention, that 5-FU is administered in molar excess relative to the eniluracil.

The dosages and schedules for eniluracil administration disclosed for embodiments of the present invention are different than those used in previous phase II and III human trials (Levin et al, Invest New Drugs 18: 383-90, 2000; Schilsky et al, J Clin Oncol: 20: 1519-26, 2002). The study described above utilized higher doses of eniluracil and 5-FU was administered simultaneously with eniluracil or only 1 hour after eniluracil administration. Although some antitumor activity was demonstrated in the phase III trial, the overall results were lower than expected, and the trial was not considered successful. It is believed that by using the methods of the present invention, improved efficacy will be obtained by ensuring that there is no excess eniluracil when administering 5-FU or a 5-FU prodrug and thus no inhibition of 5-FU activation.

Further features of the invention include pharmaceutical formulations comprising at least one pharmaceutically acceptable carrier or excipient and further comprising a DPD inhibitor and/or 5-FU or a 5-FU prodrug, either together in a single formulation or as separate formulations, for administration at separate time points according to the invention. In one embodiment, the eniluracil and 5-FU are present in one or more formulations in a ratio of about 1: 3 to 1: 20, 1: 5 to 1: 15, or 1: 8 to 1: 12. The carrier or excipient is "pharmaceutically acceptable" in the sense of being compatible with the other ingredients of the formulation and not deleterious to the patient. For example, the formulations include those suitable for oral, rectal, nasal, topical (including buccal and sublingual), vaginal and parenteral (including subcutaneous, intramuscular, intravenous and intradermal) administration. The formulations may conveniently be presented in unit dosage form and may be prepared by any of the methods well known in the art of pharmacy. The method comprises the step of bringing into association the active ingredient with a carrier which constitutes one or more accessory ingredients. In general, the formulations are prepared by uniformly and intimately bringing into association the active ingredient with liquid carriers or finely divided solid carriers or both, and then, if necessary, shaping the product.

The formulations of the present invention can be prepared and/or administered using essentially any available technique. For example, formulations of the present invention suitable for oral administration may be presented as discrete units, such as capsules, cachets or tablets, each containing a predetermined amount of the active ingredient; as a powder or granules; as a solution or suspension in an aqueous or non-aqueous liquid; or as an oil-in-water liquid emulsion or a water-in-oil liquid emulsion. The active ingredient may also be presented in the form of a pill, electuary or paste. Oral administration is generally the preferred route of administration.

For example, a tablet may be produced by compression or molding, optionally together with one or more accessory ingredients. Compressed tablets may be prepared by compressing in a suitable machine the active ingredient in a free-flowing form such as a powder or granules, optionally mixed with a binder (e.g., polyvinylpyrrolidone, gelatin, hydroxypropylmethylcellulose), lubricant, inert diluent, preservative, disintegrant (e.g., sodium starch glycolate, cross-linked polyvinylpyrrolidone, cross-linked sodium carboxymethylcellulose), surface-active or dispersing agent. Molded tablets may be prepared by molding in a suitable machine a mixture of the powdered compound moistened with an inert liquid diluent. The tablets may optionally be coated or scored and may be formulated so as to provide controlled release of the active ingredient therein, for example using hydroxypropylmethyl cellulose in varying proportions to provide the desired release profile.

For example, formulations for topical application in the oral cavity include: lozenges comprising the active ingredient in a flavoured base (bases), typically sucrose and acacia or tragacanth; lozenges comprising the active ingredient in an inert base such as gelatin and glycerin or sucrose and acacia; and mouthwashes comprising the active ingredient in a suitable liquid carrier. For example, formulations for rectal administration may be presented as a suppository with a suitable base comprising, for example, cocoa butter or a salicylate. For example, formulations for vaginal administration may be presented as pessaries, tampons, creams, gels, pastes, foams or spray formulations containing in addition to the active ingredient such carriers as are known to those skilled in the art to be appropriate.

For example, formulations for parenteral administration include aqueous and non-aqueous isotonic sterile injection solutions which may contain antioxidants, buffers, bacteriostats and solutes which render the formulation isotonic with the blood of the intended recipient; and aqueous and non-aqueous sterile suspensions which may include suspending agents and thickening agents. The formulations may be presented in unit-dose or multi-dose sealed containers, for example, ampoules and vials, and may be stored in a freeze-dried (lyophilized) condition requiring only the addition of the sterile liquid carrier, for example water for injections, immediately prior to use. Extemporaneous injection solutions and suspensions may be prepared from sterile powders, granules and tablets of the kind described above.

Typically, liquid formulations comprising one or more active agents are preferably buffered to a pH of 7-11, typically 9.5-10.5. Certain unit dosage formulations may include those containing a daily dose or unit, daily sub-dose, as described above, or suitable portions thereof, of the active ingredient.

The methods of making the DPD inhibitors and 5-FU prodrugs disclosed herein are well known and can be performed using conventional methods. For example, the DPD inhibitors mentioned above can be prepared by the methods disclosed in the following documents: heterocyclic chem.19(3)463-4(1982) for the preparation of 5-ethynyluracil; chem.soc.perkin trans.1(16), 1665-70(1981) for the preparation of 5- (2-bromovinyl) uracil, 5-bromoethynyluracil and 5- (2-bromo-1-chloroethenyl) uracil; nucleic acid chemistry, Vol.2, 927-30(1978), for the preparation of 5-cyano-uracil; nucleic acids Research, 1(1)105-7(1974), for the preparation of 5-vinyluracil; chern 17(11)415-16(1977) for the preparation of 5-trifluoromethyluracil; nucleic Acids Research 3(10), 2845(1976), for the preparation of 5- (1-chloroethenyl) uracil. Certain other compounds of the invention may be prepared according to the methods disclosed in the following references: european patent Specification No. 356166 for the preparation of 3 '-fluoro-2', 3 '-dideoxy 5-alkynyluridine compounds, such as 2', 3 '-dideoxy-5-ethynyl-3' -fluorouridine, and European patent Specification No. 272065 for the preparation of 5-alkynyluracil arabinosides, such as 1- (b-D-arabinofuranosyl) -5-prop-1-ynyluracil. The above and other synthetic techniques are well known and can be used to prepare the compounds for use in the present invention.

In one embodiment, the present invention provides a combination oral formulation wherein the DPD inhibitor and 5-FU or a 5-FU prodrug are administered together in a manner such that the components of the formulation are released into the patient's body at the desired time. Differential extended release delivery of the two components can be achieved using known techniques and materials. For example, in one embodiment, an oral formulation, such as in tablet form, may be composed of three distinct layers, as schematically depicted in fig. 3. The outer layer may comprise eniluracil in an immediate release formulation. The intermediate layer may be a time release component (e.g., a time release buffer) that delays the release of the 5-FU or 5-FU prodrug to the desired extent of the present invention, the 5-FU or 5-FU prodrug being located in an immediate release formulation of the core layer. The DPD inhibitor and 5-FU or 5-FU prodrug are formulated at appropriate dosages and ratios as disclosed herein. In a preferred embodiment, the DPD inhibitor is eniluracil and the 5-FU or 5-FU prodrug is 5-FU or capecitabine.

In another embodiment, the alternative formulation may comprise a known delivery vehicle such as a microsphere comprising 5-FU or a prodrug of 5-FU. In one embodiment, for example, 5-FU or a 5-FU prodrug can be encapsulated in a shell of a delayed-release component (e.g., a delayed-release disintegration buffer) and immediate release of the DPD inhibitor is provided by the outer layer. In a preferred embodiment, the DPD inhibitor is eniluracil and the 5-FU or 5-FU prodrug is 5-FU or capecitabine. The above and other examples of exemplary combination formulations can be designed and prepared using known techniques such that there is a suitable delay between delivery of the DPD inhibitor and the 5-FU or 5-FU prodrug in a single oral formulation.

In another embodiment, the DPD inhibitor can selectively or preferentially target cancer cells and tumors. The selective action of DPD in cancer cells and tumors allows the compounds to have a longer half-life relative to their circulating half-life, which will achieve higher steady-state levels of activated nucleotides and improved therapeutic index. In one embodiment, selective targeting of DPD inhibitors such as eniluracil to tumors can be achieved using targeting microspheres, which are well known in the art. In another embodiment, targeting is accomplished using a tissue specific receptor, such as an asialoglycoprotein (asialoglycoprotein) receptor, to target the compound to hepatocytes and liver cancer cells. For example, the targeting may be achieved by chemically or otherwise modifying the DPD inhibitor (e.g., by placing 3-6 galactose residues on eniluracil).

In another embodiment, the methods disclosed herein further comprise administering leucovorin. Leucovorin, or levofolinic acid (an active isomer of leucovorin), is commonly used in combination with 5-FU in the treatment of cancer patients. It may also be added to the dosing regimen of eniluracil and 5-FU described above. Formyltetrahydrofolate has been shown to improve the antitumor efficacy of eniluracil and 5-FU in tumor-bearing rats and tissue culture (Cao et al, Cancer Res 90: 1507. sup. 1510, 1993; Fischel et. alpha.l, Biochem Pharmacol 53: 1703. sup. 1709, 1997) and has been administered to patients who have received eniluracil and 5-FU (Schilsky et al, J Clin Oncol 4: 1450-7, 1998; Guo et al, Cancer Chemother Pharmacol 52: 79-85, 2003). Oral formulations of leucovorin are also advantageously available.

The invention may be further understood by consideration of the following non-limiting examples.

Examples

Example 1

Excess eniluracil attenuates the anti-tumor activity of eniluracil and 5-FU

Ward cancers were implanted into rats and treated with one of the following protocols after their tumors grew to 3,000mg weight, as previously disclosed (Cao et al, Cancer Res 90: 1507-1510, 1993). Rats with 3,000mg tumor mass were treated on days 0, 7 and 14 as follows.

Research arm	Treatment of
				Group of	Enuracil	Enuracil, 55 min	5-FU, 60 min
	(mg/kg)	(mg/kg)	(mg/kg)
				A	0	0	0
B	1	0	5
				C	1	25	5

Group a rats received no treatment. Group B rats were dosed intraperitoneally (ip) with 1mg/kg eniluracil (time t 0) followed by 5mg/kg5-FU intravenously (iv) at t 60. Group C rats were dosed ip with 1mg/kg eniluracil (t-0), followed by ip with 25mg/kg eniluracil at t-55 minutes, and iv with 5mg/kg5-FU at t-60 minutes. Animals were dosed 1 time per week for three weeks. Rats in group B & C were also ip dosed with 1mg/kg eniluracil on days 2 and 3 of each weekly treatment. Treatment of group C simulated a clinical trial in which high levels of eniluracil were present when 5-FU was administered.

Tumors in group a grew rapidly to 10,000mg and the rats were sacrificed. Tumors in group B rapidly eliminated, while tumors in group C had only a slight decrease in size on average. The above results indicate that excess eniluracil in group C greatly attenuated the antitumor activity of 5-FU, probably due to the interference of eniluracil with the metabolic activation of 5-FU.

Example 2

Enuracil inhibits the metabolic activation of 5-FU into active nucleotide

HEK 293 cells were initially treated with eniluracil (10. mu.M) for 1 hour. After a wash-out period of 4-48 hours, at 37 ℃ with [6-¹⁴C]-5FU (66. mu.M) for 2 hours. Control was with [6-¹⁴C]5-FU (66. mu.M) or with eniluracil (10. mu.M) and [6-¹⁴C]HEK 293 cells treated with-5-FU (66. mu.M) for 2 hours. Reverse phase HPLC with radioactive detection was used to quantify [6-¹⁴C]-5-FU catabolite/anabolite. In a separate set of experiments, the cytotoxicity of 5-FU was examined at different dosage regimens of eniluracil. HEK 293 cells were treated with a series of 5-FU concentrations for 72 hours at 37 ℃: after 1 hour of eniluracil (5 μ M) preincubation; no eniluracil; or eniluracil (5 μ M) co-administered without pre-incubation. Assessment of cytotoxicity and calculation of EC for 5-FU by MTS proliferation assay₅₀The value is obtained.

Cells were pretreated with eniluracil for 1 hour, then washed out for 36 or 48 hours, and then [6-¹⁴C]5-FU treatment, with a separate [6-¹⁴C]-5-FU treatment or eniluracil and [6-¹⁴C]Results in [6-¹⁴C]A significant increase in the formation of FUMP anabolic products (p-value < 0.05). E.g. with separate [6-¹⁴C]The 48 hour washout resulted in [6-¹⁴C]The formation of-FUMP is increased by 70%, and the formation of-FUMP is increased by 70% with eniluracil and [6-¹⁴C]Results in [6-¹⁴C]The increase in FUMP formation was 41%. In cytotoxicity experiments, 1 hour pretreatment with eniluracil increased the cytotoxicity of 5-FU, EC compared to the 5-FU treatment alone (311.4 nM. + -. 1.1) or the co-administration of EU and 5-FU without preincubation (307.8 nM. + -. 1.03)₅₀The value was reduced (264.0 nM. + -. 1.7) (mean. + -. SE) (p < 0.05).

The above results further demonstrate the role of eniluracil in inhibiting the anabolic pathway that converts 5-FU to active antitumor nucleotides, in addition to its known role in inhibiting the catabolic pathway that degrades 5-FU to an inactive form.

Example 3

Eniluracil causes an increase in plasma uridine levels

Although it is known that eniluracil inhibition results in increased uracil levels (due to DPD inhibition), inhibition of other enzymes that anabolically metabolize fluoropyrimidines is expected to quantitatively alter the levels of other anabolic products, such as uridine. The mice were administered eniluracil at doses of 2mg/kg, 25mg/kg and 100 mg/kg. Plasma samples were taken at 0 min, 15 min, 30 min, 60 min, 2 h, 24 h and 48 h. Uridine levels were determined by LC-MS technique using known techniques and standards were used to validate the assay.

Referring to fig. 2, the results of the above experiments indicate that eniluracil results in increased uridine levels after administration. This finding is consistent with the inhibitory effect of eniluracil on anabolic enzymes such as uridine phosphorylase, and further supports the role of eniluracil in inhibiting the anabolic conversion of 5-FU to active nucleotides.

From the foregoing it will be appreciated that, although specific embodiments of the invention have been described herein for purposes of illustration, various modifications may be made without deviating from the spirit and scope of the invention. Accordingly, the invention is not to be limited by the foregoing description, except as by the appended claims.

Claims (60)

1. A method of treating cancer in a patient comprising administering a DPD inhibitor first, followed by administration of 5-FU or a 5-FU prodrug, wherein the 5-FU or 5-FU prodrug is administered at a dose that is: upon its administration, the 5-FU or 5-FU prodrug is present in the patient in an amount in excess of the DPD inhibitor.

2. The method of claim 1, wherein the 5-FU or 5-FU prodrug is administered at least about 4 hours after the DPD inhibitor is administered.

3. The method of claim 1, wherein the 5-FU or 5-FU prodrug is administered at least about 12 hours after the DPD inhibitor is administered.

4. The method of claim 1, wherein the 5-FU or 5-FU prodrug is administered at least about 24 hours after the DPD inhibitor is administered.

5. The method of claim 1, wherein the 5-FU or 5-FU prodrug is administered at a time that is: at least 1-4 elimination half-lives of the DPD inhibitor have passed since the DPD inhibitor was administered.

6. The method of claim 1, wherein the DPD inhibitor is administered at a dose sufficient to reduce DPD activity in the patient to less than 5% of baseline DPD activity in the patient.

7. The method of claim 1, wherein the 5-FU or 5-FU prodrug is administered at a dose that: upon its administration, the 5-FU or 5-FU prodrug is present in the patient in an amount at least 2-fold greater than the DPD inhibitor.

8. The method of claim 1, wherein the 5-FU or 5-FU prodrug is administered at a dose that: upon its administration, the 5-FU or 5-FU prodrug is present in the patient in an amount at least 5-fold greater than the DPD inhibitor.

9. The method of claim 1, wherein the DPD inhibitor is an irreversible DPD inhibitor.

10. The method of claim 1, wherein the DPD inhibitor is a reversible DPD inhibitor.

11. The method of claim 1, wherein said 5-FU or 5-FU prodrug is selected from the group consisting ofTheir 5' -esters, including phosphate esters: 5-fluorouridine, 5-fluorocytidine, 5-fluoro-2-deoxyuridine, 5-fluoro-2-deoxycytidine, 5 ' -deoxy-4 ', 5-fluorouridine, and 5-fluorouracil, 5 ' -deoxy-5-fluorouridine, 1- (2-tetrahydrofuryl) -5-fluorouracil, 1-C_1-8Alkylcarbamoyl-5-fluorouracil derivatives, 1- (2-tetrahydrofuryl) -5-fluorouracil, 5' -deoxy-5-fluoro-N- [ (pentyloxy) carbonyl]-cytidine (capecitabine), or a compound capable of being converted in vivo into 5-FU.

12. The method of claim 1, wherein the 5-FU or 5-FU prodrug is 5-FU or capecitabine.

13. The method of claim 1, wherein the DPD inhibitor is eniluracil or a prodrug thereof.

14. The method of claim 1, wherein the DPD inhibitor is eniluracil and the 5-FU or 5-FU prodrug is 5-FU or capecitabine.

15. The method of claim 1, wherein the DPD inhibitor is eniluracil, the 5-FU or 5-FU prodrug is 5-FU, and the eniluracil is administered at a dose of about 0.8-15mg/m²。

16. The method of claim 1, wherein the DPD inhibitor is eniluracil, the 5-FU or 5-FU prodrug is 5-FU, and the eniluracil is administered at a dose of about 2.5-5mg/m²。

17. The method of claim 1, wherein the DPD inhibitor is eniluracil, the 5-FU or 5-FU prodrug is 5-FU, and the eniluracil is administered at a dose of about 5-15mg/m²。

18. The method of claim 1, wherein the DPD inhibitor is eniluracil,the 5-FU or 5-FU prodrug is 5-FU, and the eniluracil is administered at a dose of about 2.5-15mg/m²And said 5-FU is administered in a dose of about 0.5-80mg/m²。

19. The method of claim 1, wherein the DPD inhibitor is eniluracil, the 5-FU or 5-FU prodrug is 5-FU, and the eniluracil is administered at a dose of about 2.5-5mg/m²And said 5-FU is administered in a dose of about 0.5-40mg/m²。

20. The method of claim 1, wherein the DPD inhibitor comprises a 5-substituted uracil compound or a prodrug thereof.

21. The method of claim 1, wherein the DPD inhibitor comprises a uracil compound substituted at the 5-position with: a halogen atom, C_2-4Alkenyl, C substituted by halogen_2-4Alkenyl radical, C_2-6Alkynyl, C substituted by halogen_2-6Alkynyl, cyano, C_1-4Alkyl or C substituted by halogen_1-4An alkyl group.

22. The method of claim 1, wherein the DPD inhibitor comprises a uracil compound selected from the group consisting of: eniluracil, 5-propynyluracil, 5-cyanouracil, 5-propynyluracil, 5-bromoethynyluracil, 5- (1-chloroethenyl) uracil, 5-iodouracil, 5-bromovinyluracil, (E) -5- (2-bromovinyl) uracil, 5-hex-1-ynyluracil, 5-vinyluracil, 5-trifluorouracil, 5-bromouracil, and 5- (2-bromo-1-chloroethenyl) uracil.

23. The method of claim 1, wherein the DPD inhibitor is selected from the group consisting of: 5- (phenylseleno) uracil (PSU), 5- (phenylthio) uracil (PTU), 5- (phenylseleno) barbituric acid and 5- (phenylthio) barbituric acid.

24. A method of treating cancer in a patient comprising administering first eniluracil and then 5-FU, wherein the 5-FU is administered at a dose that: at the time of its administration, 5-FU is present in the patient in an amount exceeding that of the DPD inhibitor.

25. The method of claim 24, wherein the 5-FU is administered at least about 4 hours after the eniluracil is administered.

26. The method of claim 24, wherein the 5-FU is administered at least about 12 hours after the eniluracil is administered.

27. The method of claim 24, wherein the time of administration of the 5-FU is such that: at least about 1-4 elimination half-lives of eniluracil have been experienced since the administration of eniluracil.

28. The method of claim 24, wherein the eniluracil is administered at a dose sufficient to reduce DPD activity in the patient to less than 5% of baseline DPD activity in the patient.

29. The method of claim 24, wherein the 5-FU is administered at a dose that: upon its administration, the 5-FU is present in the patient in an amount at least 2-fold greater than the DPD inhibitor.

30. The method of claim 24, wherein the 5-FU is administered at a dose that: upon its administration, the 5-FU is present in the patient in an amount at least 5-fold greater than the DPD inhibitor.

31. The method of claim 24 wherein said eniluracil is administered in an amount of about 2.5-5mg/m²。

32. The method of claim 24, whereinThe dosage of the eniluracil is about 2.5-15mg/m²And said 5-FU is administered in a dose of about 0.5-40mg/m²。

33. A method of treating cancer in a patient comprising administering first eniluracil and then 5-FU, wherein said eniluracil is administered at a dose of about 2.5-15mg/m²And wherein said 5-FU is administered after having undergone at least 1-4 elimination half-lives of eniluracil since the administration thereof.

34. The method of claim 33, wherein the 5-FU is administered at least about 4 hours after the eniluracil is administered.

35. The method of claim 33, wherein the 5-FU is administered at least about 14 hours after the eniluracil is administered.

36. The method of claim 33, wherein the 5-FU is administered at least about 18 hours after the eniluracil is administered.

37. The method of claim 33, wherein the 5-FU is administered at a dose that: upon its administration, the 5-FU is present in the patient in an amount at least 2-fold greater than the DPD inhibitor.

38. The method of claim 33, wherein the 5-FU is administered at a dose that: upon its administration, the 5-FU is present in the patient in an amount at least 5-fold greater than the DPD inhibitor.

39. The method of claim 33, wherein said 5-FU is administered in a dose of about 0.5-40mg/m²。

40. A method of treating cancer in a patient comprising administering eniluracil first, followed by administration of 5-FU, wherein saidThe dosage of the eniluracil is about 2.5-15mg/m²Wherein said 5-FU is administered at least about 4 hours after the eniluracil is administered, and wherein said 5-FU is administered at a dose of about 0.5-40mg/m²。

41. The method of claim 40, wherein the 5-FU is administered at least about 14 hours after the eniluracil is administered.

42. The method of claim 40, wherein the 5-FU is administered at least about 18 hours after the eniluracil is administered.

43. A method of treating cancer in a patient comprising administering first eniluracil and then capecitabine, wherein said eniluracil is administered at a dose of about 2.5-15mg/m²And wherein said 5-FU is administered after having undergone at least 1-4 elimination half-lives of eniluracil since the administration thereof.

44. The method of claim 43, wherein the capecitabine is administered at least about 4 hours after the eniluracil is administered.

45. The method of claim 43, wherein the capecitabine is administered at least about 14 hours after the eniluracil is administered.

46. The method of claim 43, wherein the capecitabine is administered at least about 24 hours after the eniluracil is administered.

47. The method of claim 43, wherein said capecitabine is administered at a dose that is: upon its administration, the capecitabine is present in the patient in an amount at least 2-fold greater than the DPD inhibitor.

48. The method of claim 43, wherein said capecitabine is administered at a dose that is: upon its administration, the capecitabine is present in the patient in an amount at least 5-fold greater than the DPD inhibitor.

49. The method of claim 43, wherein said capecitabine is administered in a dose of about 1.5-4mg/m²。

50. An oral pharmaceutical extended release formulation comprising a DPD inhibitor and 5-FU or a 5-FU prodrug, wherein, following administration of the formulation to a patient, the 5-FU or 5-FU prodrug is not significantly released until at least about 4 hours after the DPD inhibitor has been released.

51. The formulation of claim 50, wherein the 5-FU or 5-FU prodrug is not substantially released until at least about 12 hours after the DPD inhibitor has been released.

52. The formulation of claim 50, wherein the 5-FU or 5-FU prodrug is 5-FU or capecitabine.

53. The formulation of claim 50, wherein the DPD inhibitor is eniluracil.

54. An oral pharmaceutical extended release formulation comprising a DPD inhibitor and a delivery vehicle, wherein the delivery vehicle facilitates selective targeting of the DPD inhibitor to cancer cells in a patient.

55. The formulation of claim 54, wherein the delivery vehicle is a microsphere.

56. A method of treating cancer in a patient comprising administering first eniluracil and then 5-FU, wherein eniluracil is administered at least about 0.5 hours prior to the administration of 5-FU, and wherein the 5-FU or 5-FU prodrug is administered at a dose that: upon its administration, the 5-FU or 5-FU prodrug is present in the patient in an amount in excess of the DPD inhibitor.

57. A method of treating cancer in a patient comprising administering eniluracil first, followed by 5-FU, wherein the administration is at least about 12 hours prior to the start of a 1 day, 2 times regimen for an extended period of time, at about 2.5-15mg/m²After the eniluracil is administered at about 0.5-2mg/m about 4-6 hours prior to the 1 st day 2 doses of 5-FU on each day²The dosage of eniluracil is administered.

58. The method of claim 1, wherein the dose ratio of the DPD inhibitor to the 5-FU or 5-FU prodrug is from 1: 3 to 1: 20.

59. The method of claim 1, wherein the dose ratio of the DPD inhibitor to the 5-FU or 5-FU prodrug is from 1: 5 to 1: 15.

60. The method of claim 1, wherein the dose ratio of the DPD inhibitor to the 5-FU or 5-FU prodrug is from 1: 8 to 1: 12.