WO2025214783A1

WO2025214783A1 - Monitoring unit for a torsion spring driven medicament delivery device

Info

Publication number: WO2025214783A1
Application number: PCT/EP2025/058551
Authority: WO
Inventors: Sander DEN HOED
Original assignee: SHL Medical AG
Current assignee: SHL Medical AG
Priority date: 2024-04-12
Filing date: 2025-03-28
Publication date: 2025-10-16
Anticipated expiration: 2026-10-12

Abstract

The present disclosure relates to a monitoring unit (5) for a medicament delivery device (10) having a housing (4) enclosing a plunger rod and an electrically conductive helical torsion spring (3) for propelling said plunger rod, said monitoring unit (5) comprising a sensor (51) configured to detect changes in distance between the sensor (51) and the helical torsion spring (3) as the torsion spring (3) unloads and propels the plunger rod, and configured to correlate distance changes to a movement of the plunger rod.

Description

Monitoring unit for a torsion spring driven medicament delivery device

TECHNICAL FIELD

The present invention relates to a monitoring unit for a torsion spring-based medicament delivery device, and to a kit comprising such a monitoring device and such a torsion spring driven medicament delivery device.

BACKGROUND

There are a number of medicament delivery devices that have been developed for self-administration of a medicament by a user who is usually a non- medically trained person. For many treatments, like asthma, diabetes, hormone growth, the patient has to receive doses on a regular basis and the advantage with such devices is that the patient can administer the delivery anywhere and is not bound to visit care facilities in order to receive medication.

The patient may for example initiate a medicament administration operation by moving a needle cover extending from a housing into the housing or by pushing a button provided on the medicament delivery device. This movement causes a loaded drive spring to unload, which drives a plunger rod in direction of the injection site. The plunger rod thereby displaces a plunger in a medicine container, resulting in expelling said medicine from said container.

In order to deliver large volumes of a viscous drug, preferably of a high viscous drug, a powerful drive spring is needed. Compression springs are most common in the state of the art but do not provide enough power. For such cases an helical torsion spring, which is more powerful and affordable, is preferred. In that case the medicament delivery device is said torsion spring driven. Besides that, there are many patients or elderly with motor skills difficulties who could have problems with the correct and safe handling of the medicament delivery devices. Therefore, it is beneficial if the risks of wrong handling of the device are minimized.

There is therefore an increasing demand for feedbacks to the patients indicating that the medicament delivery has started and/or ended, in a simple, reliable and consistent manner, and that are compatible with torsion spring driven medicament delivery devices.

SUMMARY

The present disclosure relates to a monitoring unit for a torsion spring-based medicament delivery device according to claim 1.

Thus, the invention relates to a monitoring unit for a medicament delivery device having a housing enclosing a plunger rod and an electrically conductive helical torsion spring for propelling said plunger rod, said monitoring unit comprising a sensor configured to detect changes in distance between the sensor and the helical torsion spring as the torsion spring unloads and propels the plunger rod, and configured to correlate distance changes to a movement of the plunger rod.

The invention relies on a characteristic of torsion springs that is, when a torsion spring is loaded, it undergoes geometrical changes. A torsion spring is wider when it is unloaded, and narrower when loaded. Thus, the diameter of a torsion spring changes depending on its loading state. Consequently, detected distance decreases between the sensor and the torsion spring result from diameter increases of the torsion spring when it unloads. In other words, during injection, an increasing metal mass can be detected by the monitoring unit. The increase of metal is clearly correlated to the progress of the injection and when the increase stops, the injection can be considered ended. Preferably, the invention comprises features according to the dependant claims.

In a non-limiting embodiment, the monitoring unit is releasably attachable to the housing of the medicament delivery device.

In a non-limiting embodiment, the sensor comprises:

- A magnetic field generator,

- A sensor circuit configured to detect changes in the magnetic field when the monitoring unit is attached to the medicament delivery device,

- A computing component configured to correlate the detected changes in magnetic field to distance changes from the torsion spring.

In a non-limiting embodiment, the sensor comprises:

- An electric field generator,

- A sensor circuit to detect changes in the electric field when the monitoring unit is attached to the medicament delivery device,

- A computing component configured to correlate the detected changes in electrical field to distance changes from the torsion spring.

In a non-limiting embodiment, the monitoring unit comprises an emitter for emitting audible or visual signals related to the movement of the plunger rod.

In a non-limiting embodiment, audible or visual signals relate to a start and/or an end of the movement of the plunger rod.

In a non-limiting embodiment, the monitoring unit comprises a transmitter for transmitting data related to the movement of the plunger rod to an external device. In a non-limiting embodiment, said data relate to a start and/or an end of the movement of the plunger rod.

The sensor of the monitoring unit may be of the inductive type, or of the capacitive type. The monitoring unit may be able to communicate with an external device. That external device may comprise a user interface configured for displaying information about the plunger rod movement (and hence, of the medicament delivery progression) or emitting audible signals indicative of said movement.

The invention also relates to a kit comprising a monitoring unit as previously defined, and comprising an external device having a user interface for displaying data related to the movement of the plunger rod received from the monitoring unit.

In a non-limiting embodiment, the monitoring unit and the external unit are configured to communicate wirelessly.

In a non-limiting embodiment, the kit comprises a medicament delivery device having a housing enclosing a plunger rod and a conductive helical torsion spring for propelling said plunger rod.

The invention also relates to a kit comprising a monitoring unit as previously defined, and comprising a medicament delivery device having a housing enclosing a plunger rod and a conductive helical torsion spring for propelling said plunger rod.

The invention is specified by the independent claims. Preferred embodiments are defined in the dependent claims. In the following description, although numerous features may be designated as optional, it is nevertheless acknowledged that all features comprised in the independent claims are not to be read as optional. In the present disclosure, when the term “distal direction” is used, this refers to the direction pointing away from the dose delivery site during use of the medicament delivery device. When the term “distal part/ end” is used, this refers to the part/end of the delivery device, or the parts/ends of the members thereof, which during use of the medicament delivery device is/are located furthest away from the dose delivery site. Correspondingly, when the term “proximal direction” is used, this refers to the direction pointing towards the dose delivery site during use of the medicament delivery device. When the term “proximal part/end” is used, this refers to the part/end of the delivery device, or the parts/ends of the members thereof, which during use of the medicament delivery device is/are located closest to the dose delivery site.

Further, the terms “longitudinal”, “longitudinally”, “axially” and “axial” refer to a direction extending from the proximal end to the distal end and along the device or components thereof, typically in the direction of the longest extension of the device and/or component.

Similarly, the terms “transverse”, “transversal” and “transversally” refer to a direction generally perpendicular to the longitudinal direction.

Further, the terms “circumference”, “circumferential”, or “circumferentially” refer to a circumference or a circumferential direction relative to an axis, typically a longitudinal axis extending in the direction of the longest extension of the device and/or component. Similarly, “radial” or “radially” refer to a direction extending radially relative to the axis, and “rotation”, “rotational” and “rotationally” refer to rotation relative to the axis.

When a component is said to move proximally, distally, axially in a proximal direction, axially in a distal direction or equivalent terms, the movement is relative to the housing of the injection device, unless mentioned otherwise.

Generally, all terms used in the claims are to be interpreted according to their ordinary meaning in the technical field, unless explicitly defined otherwise herein. All references to a/an/the element, apparatus, member, component, means, etc. are to be interpreted openly as referring to at least one instance of the element, apparatus, member component, means, etc., unless explicitly stated otherwise.

BRIEF DESCRIPTION OF THE DRAWINGS

Embodiments of the present disclosure will now be described by way of example only and with reference to the following accompanying drawings.

Fig. 1 shows portions of a torsion spring driven medicament delivery device.

Fig. 2A and Fig. 2B are cross-section views of a portion of a torsion spring based medicament delivery device, respectively before and after medicament delivery.

Fig. 3 shows a monitoring unit according to an embodiment of the invention, attached to the medicament delivery device of Fig. 2A and 2B.

DETAILED DESCRIPTION

The medicament delivery device according to the present invention can be employed for various medicament delivery devices. Thus, only the parts relevant for carrying out the disclosure will be described in detail.

In the figures, elements not essential for carrying out the invention have been omitted. In particular, not all figures show a complete outer housing, biasing members, a medicament container, cap, etc. in order not to render the depictions overly complicated and not to blur the scope of the disclosure.

In the following, the assembled state refers to a state in which the device is delivered to the patient, i.e., before activation and medicament delivery. In the assembled state, the plunger rod is in a locked position (first rotational position). In the activation state, the plunger rod is free to rotate, but still substantially locked in the axial direction. In the activated state (second rotational position), the plunger rod is free to move in the proximal direction for medicament delivery. The plunger rod may thus be displaceable along the axial direction.

In the following, the term engagement encompasses any kind of interaction between the named features such as abutment, clamping, locking etc.

Fig. 1 shows portions of an exemplary torsion spring driven medicament delivery device. The medicament delivery device may comprise a syringe 1. A medicament in the syringe 1 may be expulsed when a plunger rod 2 moves in a proximal direction within the syringe 1. The plunger rod 2 may be moved by a driver 21 and the driver 21 may be rotated by a power pack assembly. The power pack assembly may comprise a proximal rotational portion 22, a torsion spring 3, and a distal rotational portion 23.

The exemplary helical torsion spring 3 comprises a proximal hook 31 and a distal hook 32. Each of the hooks 31 and 32 is configured to engage with a respective seat or socket 21a or 23a formed at the proximal rotational portion 22 and the distal rotational portion 22, respectively, in order to transfer kinetic energy stored in the torsion spring 3 to the power pack assembly. That is, to rotate the power pack assembly in order to drive the driver 21.

One major aspect of torsion springs is that, when a torsion spring is loaded, it undergoes geometrical changes. A torsion spring is wide when it is unloaded, and becomes narrower when loaded. Thus, the diameter of the torsion spring changes depending on its loading state. This is illustrated on Fig. 2A and 2B.

Fig. 2A and Fig. 2B are cross-section views of a portion of an exemplary medicament delivery device 10 having a conductive helical drive torsion spring 3. Said medicament delivery device 10 is for instance similar to the one described in reference to Fig. 1. The torsion spring 3 extends along a longitudinal axis of the medicament delivery device 10, around a driver 21 and inside a housing 4 of the medicament delivery device 10. The housing 4 and the driver 21 both extend along the longitudinal axis of the medicament delivery device 10 as well. Fig. 2A shows the torsion spring in a loaded state, before medicament delivery from the medicament delivery device io, and Fig. 2B show the torsion spring in an unloaded state, after medicament delivery from the medicament delivery device io. The diameter of the torsion spring 3, that is to say the radial extension of the torsion spring, is shorter when the torsion spring is loaded than when the torsion spring is unloaded. Consequently, a mass of conductive metal moves towards the housing during the torsion spring unload, that is to say during medicament delivery.

The monitoring unit of the invention uses those properties. An example of a monitoring unit 5 according to the invention is illustrated on Fig. 3. The monitoring unit 5 is shown removably attached to the housing 4 of the medicament delivery device 10 of Fig. 2A and 2B.

As explained above, the monitoring unit 5 comprises a sensor 51 configured to detect changes in distance from the helical torsion spring and correlate distance changes to a movement of the plunger rod. Preferably, the sensor 51 extends along the housing 4, parallel to the longitudinal axis of the medicament delivery device 10.

The sensor 51 may be an inductive or a capacitive sensor. In case of an inductive sensor, the sensor 51 may comprise:

A magnetic field generator,

A sensor circuit configured to detect changes in the magnetic field, A computing component configured to correlate the detected changes in magnetic field to distance changes from the torsion spring, and thus to a movement of the plunger rod.

In case of a capacitive sensor, the sensor 51 may comprise:

An electric field generator,

A sensor circuit to detect changes in the electric field,

A computing component configured to correlate the detected changes in electrical field to distance changes from the torsion spring, and thus to a movement of the plunger rod. In addition to the sensor 5, the monitoring unit 5 may comprise an emitter (not illustrated) for emitting audible or visual signals related to the movement of the plunger rod. Such audible or visual signals may for instance indicate a start and/or an end of the movement of the plunger rod.

In addition or alternatively, the monitoring unit 5 my comprise a transmitter 52 for transmitting data related to the movement of the plunger rod to an external device 6, for instance a smartphone. The external device 6 may have a user interface for displaying said data. The displayed data may for instance illustrate a progression of the medicament delivery, and/or a start and/or an end of the movement of the plunger rod. The external device 6 may alternatively or in addition be configured to emit audible signals providing feedback to the patient that the medicament delivery has started and/or is ongoing and/or has finished. The communication between the monitoring unit 5 and the external device 6 is preferably wireless, for instance performed via Bluetooth.

The delivery devices described herein can be used for the treatment and/ or prophylaxis of one or more of many different types of disorders.

Exemplary disorders include, but are not limited to: rheumatoid arthritis, inflammatory bowel diseases (e.g. Crohn’s disease and ulcerative colitis), hypercholesterolaemia and/or dyslipidemia, cardiovascular disease, diabetes (e.g. type 1 or 2 diabetes), psoriasis, psoriatic arthritis, spondyloarthritis, hi dradenitis suppurativa, Sjogren's syndrome, migraine, cluster headache, multiple sclerosis, neuromyelitis optica spectrum disorder, anaemia, thalassemia, paroxysmal nocturnal hemoglobinuria, hemolytic anaemia, hereditary angioedema, systemic lupus erythematosus, lupus nephritis, myasthenia gravis, Behqet's disease, hemophagocytic lymphohistiocytosis, atopic dermatitis, retinal diseases (e.g., age-related macular degeneration, diabetic macular edema), uveitis, infectious diseases, bone diseases (e.g., osteoporosis, osteopenia), asthma, chronic obstructive pulmonary disease, thyroid eye disease, nasal polyps, transplant, acute hypoglycaemia, obesity, anaphylaxis, allergies, sickle cell disease, Alzheimer’s disease, Parkinson’s disease, dementia with Lewy bodies, systemic infusion reactions, immunoglobulin E (IgE)-mediated hypersensitivity reactions, cytokine release syndrome, immune deficiencies (e.g., primary immunodeficiency, chronic inflammatory demyelinating polyneuropathy), enzyme deficiencies (e.g., Pompe disease, Fabry disease, Gaucher disease), growth factor deficiencies, hormone deficiencies, coagulation disorders (e.g., hemophilia, von Willebrand disease, Factor V Leiden), and cancer.

Exemplary types of drugs that could be included in the delivery devices described herein include, but are not limited to, small molecules, hormones, cytokines, blood products, enzymes, vaccines, anticoagulants, immunosuppressants, antibodies, antibody-drug conjugates, neutralizing antibodies, reversal agents, radioligand therapies, radioisotopes and/or nuclear medicines, diagnostic agents, bispecific antibodies, proteins, fusion proteins, peptibodies, polypeptides, pegylated proteins, protein fragments, nucleotides, protein analogues, protein variants, protein precursors, protein derivatives, chimeric antigen receptor T cell therapies, cell or gene therapies, oncolytic viruses, or immunotherapies.

Exemplary drugs that could be included in the delivery devices described herein include, but are not limited to, immuno-oncology or bio-oncology medications such as immune checkpoints, cytokines, chemokines, clusters of differentiation, interleukins, integrins, growth factors, coagulation factors, enzymes, enzyme inhibitors, retinoids, steroids, signaling proteins, pro- apoptotic proteins, anti-apoptotic proteins, T-cell receptors, B-cell receptors, or costimulatory proteins.

Exemplary drugs that could be included in the delivery devices described herein include, but are not limited to, those exhibiting a proposed mechanism of action, such as human epidermal growth factor receptor 2 (HER-2) receptor modulators, interleukin (IL) modulators, interferon (IFN) modulators, complement modulators, glucagon-like peptide-i (GLP-i) modulators, glucose-dependent insulinotropic polypeptide (GIP) modulators, cluster of differentiation 38 (CD38) modulators, cluster of differentiation 22 (CD22) modulators, Ci esterase modulators, bradykinin modulators, C-C chemokine receptor type 4 (CCR4) modulators, vascular endothelial growth factor (VEGF) modulators, B-cell activating factor (BAFF), P-selectin modulators, neonatal Fc receptor (FcRn) modulators, calcitonin gene-related peptide (CGRP) modulators, epidermal growth factor receptor (EGFR) modulators, cluster of differentiation 79B (CD79B) modulators, tumor- associated calcium signal transducer 2 (Trop-2) modulators, cluster of differentiation 52 (CD52) modulators, B-cell maturation antigen (BCMA) modulators, enzyme modulators, platelet-derived growth factor receptor A (PDGFRA) modulators, cluster of differentiation 319 (CD319 or SLAMF7) modulators, programmed cell death protein 1 and programmed death-ligand 1 (PD-1/PD-L1) inhibitors/modulators, B-lymphocyte antigen cluster of differentiation 19 (CD19) inhibitors, B-lymphocyte antigen cluster of differentiation 20 (CD20) modulators, cluster of differentiation 3 (CD3) modulators, cytotoxic T-lymphocyte-associated protein 4 (CTLA-4) inhibitors, T-cell immunoglobulin and mucin-domain containing-3 (TIM-3) modulators, T cell immunoreceptor with Ig and ITIM domains (TIGIT) modulators, V-domain Ig suppressor of T cell activation (VISTA) modulators, indoleamine 2,3-dioxygenase (IDO or INDO) modulators, poliovirus receptor-related immunoglobulin domain-containing protein (PVRIG) modulators, lymphocyte-activation gene 3 (LAG3; also known as cluster of differentiation 223 or CD223) antagonists, cluster of differentiation 276 (CD276 or B7-H3) antigen modulators, cluster of differentiation 47 (CD47) antagonists, cluster of differentiation 30 (CD30) modulators, cluster of differentiation 73 (CD73) modulators, cluster of differentiation 66 (CD66) modulators, cluster of differentiation W137 (CDW137) agonists, cluster of differentiation 158 (CD158) modulators, cluster of differentiation 27 (CD27) modulators, cluster of differentiation 58 (CD58) modulators, cluster of differentiation 80 (CD80) modulators, cluster of differentiation 33 (CD33) modulators, cluster of differentiation 159 (CD159 or NKG2) modulators, glucocorticoid-induced TNFR-related (GITR) protein modulators, Killer Ig- like receptor (KIR) modulators, growth arrest-specific protein 6 (GAS6)/AXL pathway modulators, A proliferation-inducing ligand (APRIL) receptor modulators, human leukocyte antigen (HLA) modulators, epidermal growth factor receptor (EGFR) modulators, B-lymphocyte cell adhesion molecule modulators, cluster of differentiation W123 (CDW123) modulators, Erbb2 tyrosine kinase receptor modulators, endoglin modulators, mucin modulators, mesothelin modulators, hepatitis A virus cellular receptor 2 (HAVCR2) antagonists, cancer-testis antigen (CTA) modulators, tumor necrosis factor receptor superfamily, member 4 (TNFRSF4 or 0X40) modulators, adenosine receptor modulators, inducible T cell co-stimulator (ICOS) modulators, cluster of differentiation 40 (CD40) modulators, tumorinfiltrating lymphocytes (TIL) therapies, or T-cell receptor (TCR) therapies.

Exemplary drugs that could be included in the delivery devices described herein include, but are not limited to: etanercept, abatacept, adalimumab, evolocumab, exenatide, secukinumab, erenumab, galcanezumab, fremanezumab-vfrm, alirocumab, methotrexate (amethopterin), tocilizumab, interferon beta-ia, interferon beta-ib, peginterferon beta-ia, sumatriptan, darbepoetin alfa, belimumab, sarilumab, semaglutide, dupilumab, reslizumab, omalizumab, glucagon, epinephrine, naloxone, insulin, amylin, vedolizumab, eculizumab, ravulizumab, crizanlizumab-tmca, certolizumab pegol, satralizumab, denosumab, romosozumab, benralizumab, emicizumab, tildrakizumab, ocrelizumab, ofatumumab, natalizumab, mepolizumab, risankizumab-rzaa, ixekizumab, and immune globulins.

Exemplary drugs that could be included in the delivery devices described herein may also include, but are not limited to, oncology treatments such as ipilimumab, nivolumab, pembrolizumab, atezolizumab, durvalumab, avelumab, cemiplimab, rituximab, trastuzumab, ado-trastuzumab emtansine, fam-trastuzumab deruxtecan-nxki, pertuzumab, transtuzumab-pertuzumab, alemtuzumab, belantamab mafodotin-blmf, bevacizumab, blinatumomab, brentuximab vedotin, cetuximab, daratumumab, elotuzumab, gemtuzumab ozogamicin, 90-Yttrium-ibritumomab tiuxetan, isatuximab, mogamulizumab, moxetumomab pasudotox, obinutuzumab, ofatumumab, olaratumab, panitumumab, polatuzumab vedotin, ramucirumab, sacituzumab govitecan, tafasitamab, or margetuximab.

Exemplary drugs that could be included in the delivery devices described herein include “generic” or biosimilar equivalents of any of the foregoing, and the foregoing molecular names should not be construed as limiting to the “innovator” or “branded” version of each, as in the non-limiting example of innovator medicament adalimumab and biosimilars such as adalimumab- afzb, adalimumab-atto, adalimumab-adbm, and adalimumab-adaz.

Exemplary drugs that could be included in the delivery devices described herein also include, but are not limited to, those used for adjuvant or neoadjuvant chemotherapy, such as an alkylating agent, plant alkaloid, antitumor antibiotic, antimetabolite, or topoisomerase inhibitor, enzyme, retinoid, or corticosteroid. Exemplary chemotherapy drugs include, by way of example but not limitation, 5-fluorouracil, cisplatin, carboplatin, oxaliplatin, doxorubicin, daunorubicin, idarubicin, epirubicin, paclitaxel, docetaxel, cyclophosphamide, ifosfamide, azacitidine, decitabine, bendamustine, bleomycin, bortezomib, busulfan, cabazitaxel, carmustine, cladribine, cytarabine, dacarbazine, etoposide, fludarabine, gemcitabine, irinotecan, leucovorin, melphalan, methotrexate, pemetrexed, mitomycin, mitoxantrone, temsirolimus, topotecan, valrubicin, vincristine, vinblastine, or vinorelbine.

Exemplary drugs that could be included in the delivery devices described herein also include, but are not limited to, analgesics (e.g., acetaminophen), antipyretics, corticosteroids (e.g. hydrocortisone, dexamethasone, or methylprednisolone), antihistamines (e.g., diphenhydramine or famotidine), antiemetics (e.g., ondansetron), antibiotics, antiseptics, anticoagulants, fibrinolytics (e.g., recombinant tissue plasminogen activator [r-TPA]), antithrombolytics, or diluents such as sterile water for injection (SWFI), 0.9% Normal Saline, 0.45% normal saline, 5% dextrose in water, 5% dextrose in 0.45% normal saline, Lactated Ringer’s solution, Heparin Lock Flush solution, loo U/mL Heparin Lock Flush Solution, or 5000 U/mL Heparin Lock Flush Solution.

Pharmaceutical formulations including, but not limited to, any drug described herein are also contemplated for use in the delivery devices described herein, for example pharmaceutical formulations comprising a drug as listed herein (or a pharmaceutically acceptable salt of the drug) and a pharmaceutically acceptable carrier. Such formulations may include one or more other active ingredients (e.g., as a combination of one or more active drugs), or may be the only active ingredient present, and may also include separately administered or co-formulated dispersion enhancers (e.g. an animal-derived, human-derived, or recombinant hyaluronidase enzyme), concentration modifiers or enhancers, stabilizers, buffers, or other excipients.

Exemplary drugs that could be included in the delivery devices described herein include, but are not limited to, a multi-medication treatment regimen such as AC, Dose-Dense AC, TCH, GT, EC, TAC, TC, TCHP, CMF, FOLFOX, mF0LF0X6, mFOLFOXy, FOLFCIS, CapeOx, FLOT, DCF, FOLFIRI, FOLFIRINOX, FOLFOXIRI, IROX, CHOP, R-CHOP, RCHOP-21, Mini- CHOP, Maxi-CHOP, VR-CAP, Dose-Dense CHOP, EPOCH, Dose-Adjusted EPOCH, R-EPOCH, CODOX-M, IVAC, HyperCVAD, R-HyperCVAD, SC- EPOCH-RR, DHAP, ESHAP, GDP, ICE, MINE, CEPP, CDOP, GemOx, CEOP, CEPP, CHOEP, CHP, GCVP, DHAX, CALGB 8811, HIDAC, MOpAD, 7 + 3, 5 +2, 7 + 4, MEC, CVP, RBAC500, DHA-Cis, DHA-Ca, DHA-Ox, RCVP, RCEPP, RCEOP, CMV, DDMVAC, GemFLP, ITP, VIDE, VDC, VAI, VDC-IE, MAP, PCV, FCR, FR, PCR, HDMP, OFAR, EMA/CO, EMA/EP, EP/EMA, TP/TE, BEP, TIP, VIP, TPEx, ABVD, BEACOPP, AVD, Mini-BEAM, IGEV, C- MOPP, GCD, GEMOX, CAV, DT-PACE, VTD-PACE, DCEP, ATG, VAC, VelP, OFF, GTX, CAV, AD, MAID, AIM, VAC-IE, ADOC, or PE.

Various modifications to the embodiments described are possible and will occur to those skilled in the art without departing from the invention which is defined by the following claims.

Claims

1. A monitoring unit (5) for a medicament delivery device (10) having a housing (4) enclosing a plunger rod and an electrically conductive helical torsion spring (3) for propelling said plunger rod, said monitoring unit (5) comprising a sensor (51) configured to detect changes in distance between the sensor (51) and the helical torsion spring (3) as the torsion spring (3) unloads and propels the plunger rod, and configured to correlate distance changes to a movement of the plunger rod.

2. A monitoring unit (5) according to claim 1, wherein the monitoring unit (5) is releasably attachable to the housing (4) of the medicament delivery device (10).

3. A monitoring unit (5) according to claims 1 or 2, wherein the sensor (51) comprises:

- A magnetic field generator,

4. A monitoring unit (5) according to claims 1 or 2, wherein the sensor (51) comprises:

- An electric field generator,

5. A monitoring unit (5) according to any of the previous claims, comprising an emitter for emitting audible or visual signals related to the movement of the plunger rod.

6. A monitoring unit (5) according to the previous claim, wherein audible or visual signals relate to a start and/ or an end of the movement of the plunger rod.

7. A monitoring unit (5) according to any of the previous claims, comprising a transmitter (51) for transmitting data related to the movement of the plunger rod to an external device (6).

8. A monitoring unit (5) according to the previous claim, wherein said data relate to a start and/or an end of the movement of the plunger rod.

9. A kit comprising a monitoring unit (5) according to claim 7 or 8, and comprising an external device (6) having a user interface for displaying data related to the movement of the plunger rod received from the monitoring unit (5).

10. A kit according to the previous claim, wherein the monitoring unit (5) and the external unit (6) are configured to communicate wirelessly.

11. A kit according to claim 9 or claim 10, comprising a medicament delivery device (10) having a housing (4) enclosing a plunger rod and a conductive helical torsion spring (3) for propelling said plunger rod.

12. A kit comprising a monitoring unit (5) according to any of claims 1 to 8, and comprising a medicament delivery device (10) having a housing (4) enclosing a plunger rod and a conductive helical torsion spring (3) for propelling said plunger rod.