Auto injector

Abstract

The invention provides an auto injector for administering a medicament, comprising a container holder; a container containing the medicament and comprising a piston; a plunger rod; and a drive module configured to move the plunger rod in a proximal direction for administering the medicament and to move the plunger rod in a distal direction for plunger rod retraction; and a retraction prevention structure configured to prevent retraction of the piston upon retraction of the plunger rod.

Description

[0001] Auto injector

[0002] TECHNICAL FIELD

[0003] The present disclosure relates to an auto injector, in particular to an auto injector for administering a medicament.

[0004] BACKGROUND

[0005] Reusable auto injectors are known in the field, of a type having a plunger rod that retracts after drug delivery and thus releases the force applied to a piston in a drug container. If plunger rod retraction happens when the needle is still inside the body of the patient or when the auto injector has not been fully lifted from injection site, liquids from patient's body might be extracted into the container as the force applied to the piston is released. The backflow might include delivered drug and affect the required dose of medicament.

[0006] SUMMARY

[0007] Thus, an object underlying the present invention is to provide an auto injector that reduces the risk of backflow into the container. This object may be achieved with an auto injector according to the independent claims. Preferred aspects are defined in the dependent claims.

[0008] According to a first aspect of the present disclosure, an auto injector for administering a medicament is provided comprising a container holder; a container containing the medicament and comprising a piston; a plunger rod; and a drive module configured to move the plunger rod in a proximal direction for administering the medicament and to move the plunger rod in a distal direction for plunger rod retraction. The auto injector further comprises a retraction prevention structure configured to prevent retraction of the piston upon retraction of the plunger rod.

[0009] According to a first preferred embodiment, the retraction prevention structure is an auxiliary component arranged between the piston and the plunger rod. The auxiliary component may be a compressible and radially expandable material. For example, the auxiliary component is a rubber-like material. It is also preferred that the auxiliary component is of a material that maintains its expanded shape after being compressed.

[0010] According to this embodiment, the auxiliary component in its expanded state contacts the inner surface of the container wall.

[0011] According to an alternative embodiment, the auxiliary component comprises a magnetic material. The auto injector in this embodiment may comprise one or more magnets interacting with the magnetic material of the auxiliary component to attract and maintain the auxiliary component in its proximal position. Preferably, the one or more magnets are arranged at a proximal area of the container.

[0012] In another embodiment, the retraction prevention structure is a proximal area of the container having a larger diameter than an area distal therefrom. The piston may be of a compressible material. Preferably, the piston assumes an expanded state when being pushed by the plunger rod into the proximal area having larger diameter.

[0013] The container wall may have a stepped configuration from the distal area to the proximal area. The stepped configuration of the container wall may be configured to prevent retraction of the piston.

[0014] According to another embodiment, the retraction prevention structure is formed by an intermediate portion or constriction of the container having a smaller diameter than an area proximal and distal therefrom. The intermediate portion may be annular in shape. Alternatively, or in addition, the intermediate portion may have two or more separate radially inward deformations of the container wall. The two or more inward deformations may be arranged along a circular path on the container wall. The intermediate portion may separate a proximal area and a distal area of the container such that the proximal area has an axial length to accommodate therein the piston in its proximal position.

[0015] According to an embodiment, the retraction prevention structure is a structure at the inner container wall configured to provide increased friction between the inner container wall and the outer circumferential surface of the piston. The retraction prevention structure may be at a proximal area of the container. The retraction prevention structure may be one or more protrusions at the inner container wall.

[0016] According to one embodiment, the one or more protrusions extend in circumferential direction. The protrusions may be spaced from each other in circumferential and or axial direction. For example, the one or more protrusions are annular.

[0017] Alternatively, the one or more protrusions extend axially in proximal-distal direction. The protrusions may have the same or different lengths. The length of the one or more protrusions may be equal to or smaller than the axial length of the piston. The length of the one or more protrusions may be at least half the axial length of the piston.

[0018] According to an embodiment, the retraction prevention structure is an auxiliary module arranged in proximal-distal direction between the piston and the plunger rod. The auxiliary module may comprise a first component having a proximal surface portion in contact with the piston, a second component having a distal surface portion in contact with the plunger rod, and an interface component operatively arranged between the first component and the second component.

[0019] The first component may have a generally cylindrical shape. The second component may have a generally cylindrical shape.

[0020] The second component may in part be received within the first component. The first component and the second component may be mechanically connected to each other, wherein the mechanical connection is configured to prevent separation of the first component from the second component in distal direction and to allow displacement of the first component relative to the second component in proximal direction.

[0021] The interface component may be a spring member. The spring member may be arranged to bias the second component in distal direction.

[0022] The first component may comprise one or more retraction prevention member configured to prevent retraction of the auxiliary module upon being activated.

[0023] The mechanical connection may be configured to allow displacement of the second component relative to the first component causing activation of the one or more retraction prevention member. The mechanical connection may be configured to allow displacement of the second component from a first axial and rotational position to a second position being at least rotationally different from the first position. The displacement of the second component from the first position to the second position may cause the mechanical connection to activate the one or more retraction prevention member.

[0024] The one or more retraction prevention member are preferably flexible arms configured to be pushed radially outwards against the container wall.

[0025] The second component may comprise one or more protrusions. The protrusion(s) is / are engageable with a corresponding bayonet feature(s) that may be provided on the first component. The bayonet structure is arranged such that it prevents that the second component is moved distally relative to the first component due to the bias force of the spring member.

[0026] The second component may further comprise one or more guide protrusions. Preferably, two guide protrusions are provided being arranged opposite to each other by 180°. The guide protrusions interact with guide surfaces which may be provided on the first component. The interaction of the guide protrusions and the guide surfaces is such that upon an axial force being applied on the second component by the plunger rod, the second component is moved towards the first component against the bias force of the spring member. Due to this movement, the guide protrusions slide along the guide surfaces, which results in an axial-rotational displacement of the second component relative to the first component. During this movement, the protrusions are moved in circumferential direction relative to the bayonet structure so that they are actually released from the bayonet structure.

[0027] According to a second aspect, the disclosure provides an auto injector for administering a medicament, comprising a container holder; a displaceable needle cover; a container containing the medicament and comprising a piston; a plunger rod for delivery of the medicament; and a drive module configured for proximal movement of the plunger rod for administering the medicament and for distal movement of the plunger rod for plunger rod retraction. The auto injector further comprises a sensor for sensing position of the needle cover; wherein the drive module is configured to initiate plunger rod retraction if the sensor senses the needle cover assuming a release position.

[0028] The sensor for sensing position of the needle cover may be a switch. The switch may be configured to be in a deactivated state prior to use of the auto injector. The switch may be configured to be in an activated state when the needle cover is displaced upon use of the auto injector. The switch may be configured to be in a deactivated state when the needle cover is released at completion of the use of the auto injector.

[0029] 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 under 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 under use of the medicament delivery device is / are located closest to the dose delivery site.

[0030] Further, the term "longitudinal", "longitudinally", "axially" or "axial" refer to a direction extending from the proximal end to the distal end, typically along the device or components thereof in the direction of the longest extension of the device and / or component.

[0031] Similarly, the terms "transverse", "transversal" and "transversally" refer to a direction generally perpendicular to the longitudinal direction.

[0032] Further, the terms "circumference", "circumferential", or "circumferentially" refer to a circumference or a circumferential direction relative to an axis, typically a central axis extending in the direction of the longest extension of the device and / or component.

[0033] 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.

[0034] BRIEF DESCRIPTION OF THE DRAWINGS

[0035] The specific embodiments of the inventive concept will now be described, by way of example, with reference to the accompanying drawings, in which:

[0036] Figs. 1A to 1C are a schematic illustration of a container with a retraction prevention structure according to a first embodiment of present invention;

[0037] Figs. 2A and 2B are a schematic illustration of a container with a retraction prevention structure according to a second embodiment of the present invention;

[0038] Figs. 3A and 3B are a schematic illustration of a container with a retraction prevention structure according to a third embodiment of the present invention;

[0039] Figs. 4A and 4B are a schematic illustration of a container with a retraction prevention structure according to a fourth embodiment of the present invention;

[0040] Figs. 5A and 5B are a schematic illustration of a container with a retraction prevention structure according to a fifth embodiment of the present invention;

[0041] Fig. 6 is a schematic illustration of a container with a retraction prevention structure according to a sixth embodiment of the present invention; Figs. 7A to 7E are perspective drawings of a retraction prevention structure according to a seventh embodiment of the present invention;

[0042] Fig. 8 shows the container with the retraction prevention structure of the seventh embodiment of the present invention arranged distal of the piston;

[0043] Figs. 9 to 11 show perspective explodes views of the retraction prevention structure according to the seventh embodiment of the present invention; and

[0044] Fig. 12A to 12C illustrate an eighth embodiment of the present invention.

[0045] DETAILED DESCRIPTION

[0046] The inventive concept will now be described more fully hereinafter with reference to the accompanying drawings, in which exemplifying embodiments are shown. The inventive concept may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein; rather, these embodiments are provided by way of example so that this disclosure will be thorough and complete, and will fully convey the scope of the inventive concept to those skilled in the art. Like numbers refer to like elements throughout the description.

[0047] Fig. 1 is a schematic illustration of a container with a retraction prevention structure according to the first embodiment of the present invention to be used in an auto injector for administering a medicament. Figs. 1A to 1C show the container 1 with the needle 2 and the piston 3 arranged within the container 1. Although the needle 2 is shown in various drawings, the needle 2 is not an essential element for the present invention. The sequence of Figs. 1A to 1C also shows the plunger rod 4 in different positions. Fig. 1A shows the plunger rod 4 in a schematic initial state, i.e., offset from the container 1. In Fig. IB, the plunger rod 4 is shown during administration of the medicament, with its direction of movement illustrated by the arrow. Fig. 1C shows the plunger rod 4 moved in distal direction for plunger rod retraction, with the direction of this motion again indicated by an arrow.

[0048] Figs. 1A to 1C also illustrate a retraction prevention structure that in this embodiment is an auxiliary component 10 arranged distally of the piston 3, e.g., between the piston 3 and the plunger rod 4. In the first embodiment of the present invention, the auxiliary component 10 is a compressible and radially expandable material. As can be seen in Fig. 1A, the auxiliary component 10 in this exemplary embodiment initially has a diameter that is smaller than the inner diameter of the container 1 so that a radial gap is visible between the outer surface of the auxiliary component 10 and the inner surface of the container wall 11. When the plunger rod 4 contacts the auxiliary component 10 and a force is then applied by the plunger rod 4 on the auxiliary component 10, the auxiliary component 10 is deformed. Specifically, its radial extent increases. For example, it may be compressed axially and expanded radially. The deformed or radially expanded state of the auxiliary component 10 is also shown in Fig. 1C. Fig. 1C illustrates the end of the administration process when the piston 3 has reached its proximal position in the container 1. As can also be seen in Fig. 1C, the auxiliary component 10 is of a material that maintains its expanded shape or state after being compressed. Thus, the auxiliary component 10 in its radially expanded state contacts the inner surface of the container wall 11. The auxiliary component 10 is of a rubber-like material that maintains its expanded or deformed shape, or is of a plastically deformable material that maintains its expanded or deformed shape. Due to the fact that the expanded auxiliary component 10 contacts with its outer surface the inner wall 11 of the container 1, friction is created between these two components, i.e., at the contact surface between the auxiliary component 10 and the inner surface of the container wall 11. This prevents the piston 3 from retracting when the plunger rod 4 is retracted. In other words, the piston 3 is maintained in its proximal position within the container 1 due to the retraction prevention structure 10, i.e., the auxiliary component, of the first embodiment of the present invention.

[0049] Figs. 2A and 2B illustrate a second embodiment of the present invention. Figs. 2A and 2B show the container 1 with its needle 2 (again, the needle 2 being an optional component), and a piston 3 is arranged within the container 1. An auxiliary component 30 is provided as retraction prevention structure to prevent retraction of the piston 3 upon retraction of the plunger rod (not shown in Figs. 2A and 2B). The auxiliary component 30 is arranged at the distal side of the piston 3. In this embodiment, the auxiliary component 30 comprises a magnetic material. Furthermore, the auto injector in the second embodiment comprises one or more magnets 21, 22. The magnets 21, 22 are configured to interact with the magnetic material of the auxiliary component 30. This interaction between the magnets 21, 22 and the magnetic material causes the auxiliary component 30 to be attracted by the magnets 21, 22, and this magnetic force maintains the auxiliary component 30 in its proximal position, as illustrated in Fig. 2B. Thus, due to the magnetic force between the one or more magnets 21, 22, and the auxiliary component 30, the piston 3 is prevented from retracting distally.

[0050] Preferably, the one or more magnets 21, 22 are arranged at a proximal area of the container 1. In the example shown in Fig. 2B, the one or more magnets 21, 22 somewhat overlap with the piston 3 in longitudinal direction. However, the magnets 21, 22, may be arranged more proximally compared to what is shown in Fig. 2B so that there is no overlap with the piston 3 or even with an axial gap between the magnets 21, 22 and the piston 3. On the other hand, the magnets 21, 22 may be arranged in the proximal area of the container 1 such that there is a full overlap with the piston 3 in its proximal position.

[0051] A third preferred embodiment of the present invention is illustrated in Figs. 3A and 3B. In this embodiment, the container 1 has a proximal area 40 that has a larger diameter than an area 41 being distal therefrom. The proximal area 40 is the retraction prevention structure in this embodiment. Preferably, there is a stepped configuration 43 between the proximal area 40 with a larger diameter, and the distal area 41. As can be seen in Figs. 3A and 3B, the piston 3 upon being moved proximally by the plunger rod (not shown in Figs. 3A and 3B but illustrated by the arrow) will expand into the proximal area 40 having a larger diameter. Thus, the piston 3 is of a compressible material and is initially arranged in the distal area 41 in a compressed state. However, the piston 3 assumes an expanded state when being pushed by the plunger rod into the proximal area 40 having the larger diameter. The stepped configuration 43 of the container wall 11 is configured to prevent retraction of the piston 3 from the proximal area 40 back into the distal area 41.

[0052] According to the fourth and fifth embodiments of the present invention illustrated in Figs. 4A, 4B, 5A, and 5B, the retraction prevention structure is a structure at the inner container wall 11 that is configured to provide increased friction between the inner container wall 11 and the outer circumferential surface of the piston 3.

[0053] In the fourth embodiment of Figs. 4A and 4B, the retraction prevention structure is located at a proximal area 51 of the container 1. In particular, the retraction prevention structure is provided in the form of one or more protrusions 50 at the inner container wall 11. In the embodiment in Figs. 4A and 4B, three protrusions 50 are shown. However, a single protrusion 50 or two or more than three protrusions 50 are also encompassed by the present invention. The one or more protrusions 50 extend in circumferential direction at the inner container wall 11. The protrusions 50 are spaced from each other in axial direction (in the case of more than one protrusion, as illustrated in Figs. 4A and 4B for three protrusions 50). However, protrusions 50 can alternatively be provided being spaced from each other in circumferential direction. Thus, when seen along a circular path in circumferential direction, one or more arc-shaped protrusions can be provided being spaced from each other in circumferential direction. Such arc-shaped and spaced protrusions can also be provided along two or more axially spaced circular paths at the inner container wall 11. Alternatively, one or more annular protrusions are provided being spaced in axial direction from each other.

[0054] According to the alternative fifth embodiment shown in Figs. 5A and 5B, the one or more protrusions 60 extend at the inner container wall 11 in an axial direction, e.g., a proximal- distal direction. Although Fig. 5B illustrates six protrusions, a single protrusion, or any number of protrusions between one and six, and also larger than six are encompassed by the present invention. These axial protrusions 60 can have the same length in comparison to each other or can have different lengths. The length of the one or more protrusions 60 is equal to or smaller than the axial length of the piston 3 in the illustrated embodiment. In other embodiments, the length of the one or more protrusions 60 is equal to or greater than the axial length of the piston 3. In Fig. 5A, the piston 3 is shown in its initial position, and in Fig. 5B, the piston 3 is shown in its proximal position being held in this proximal position due to the friction between the outer surface of the piston 3 and the protrusion 60 at the inner container wall 11. This prevents retraction of the piston 3 upon retraction of the plunger rod 4. Preferably, the length of the one or more protrusions 60 is at least half the length of the piston 3 in order to provide sufficient friction between the piston 3 and the inner container wall 11.

[0055] Fig. 6 shows a sixth embodiment of the present invention. In the sixth embodiment, the retraction prevention structure is formed by an intermediate portion 70 of the container 1. The intermediate portion 70 has a smaller diameter than areas of the container 1 that are proximal and distal therefrom. Preferably, the intermediate portion 70 is angular in shape. For example, this intermediate portion, or constriction, is formed by applying a force on the heated and softened container in order to permanently deform the container wall 11 inwards. The intermediate portion 70 may be annular in shape. Alternatively, the intermediate portion has two or more separate radially inward deformations at the container wall 11. The two or more inward deformations are arranged along a circular path on the inner container wall 11. In the sixth embodiment, the intermediate portion or constriction 70 separates a proximal area 71 and a distal area 72 of the container 1 from each other. The proximal area 71 has an axial length to accommodate therein the piston 3 in its proximal position. The piston 3 is thereby of a material that is compressible in order to pass by the intermediate portion 70 in order to reach the proximal area 71. The reduced diameter of the intermediate portion 70 prevents a retraction of the piston 3 when the plunger rod is retracted after administration of the medicament.

[0056] Figs. 7 to 11 illustrate a seventh embodiment of the retraction prevention structure according to the present invention. In this embodiment, the retraction prevention structure is an auxiliary module 80 that is arranged in proximal-distal direction between the piston rod 3 and the plunger rod 4. The auxiliary module 80, in this embodiment, consists of three components. It particularly comprises a first component 81 having a proximal surface portion in contact with the piston 3, and a second component 82 having a distal surface portion in contact with the plunger rod 4. An interface component 83 is operatively arranged between the first component 81 and the second component 82. These three components 81, 82, 83 are shown, for example, in Figs. 7A, 7B, 9, 10, and 11. The first component 81 has a generally cylindrical shape, and the second component 82 also has a generally cylindrical shape. The second component 82, which may be a spring member, is in part received within the first component 81, as shown in Fig. 7B. The first component 81 and the second component 82 are mechanically connected to each other, and the details of the mechanical connection are described further below. In particular, the mechanical connection between the first component 81 and the second component 82 is configured to prevent separation of the first component 81 from the second component 82 in distal direction. However, the mechanical connection is configured to allow displacement of the first component 81 relative to the second component 82 in proximal direction. The spring member, being the interface component 83, is arranged to bias the second component 82 in distal direction, as also shown in Fig. 7B.

[0057] The first component 81 comprises one or more retraction prevention members 84, as shown, for example, in Figs. 9 to 11. These one or more retraction prevention members 84 are configured to prevent retraction of the auxiliary module 80 as soon as the retraction prevention member(s) 84 is / are activated. The activation of the retraction prevention member(s) 84 is caused by the mechanical connection that is configured to allow displacement of the second component 82 relative to the first component 81.

[0058] As can be seen in Figs. 9 to 11, the second component 82 comprises, e.g., two protrusions 85. In the drawings, only one protrusion 85 is clearly visible. The second protrusion 85 is spaced circumferentially from the first protrusion by 180°, e.g., opposite to the first protrusion 85, and hidden from view in the drawings. The protrusion 85 is engageable with a bayonet feature 86 that can be seen in Fig. 11. A bayonet feature 86 is provided in the first component 81 corresponding to each protrusion 85. The bayonet structure 86 prevents the second component 82 from being moved distally relative to the first component 81 due to the bias force of the spring member 83. Thus, in the initial position of the auxiliary module 80, the protrusions 85 are received by the bayonet structure 86. This is also shown in Fig. 7C.

[0059] The second component 82 further comprises a guide protrusion 87. In the illustrated example, two guide protrusions 87 are provided being arranged opposite to each other, e.g., spaced circumferentially by 180°. The guide protrusions 87 interact with guide surfaces 88, one of which is shown in Figs. 10 and 11. The interaction of the guide protrusions 87 and the guide surfaces 88 is such that upon an axial force being applied on the second component 82 by the plunger rod 4, the second component 82 is moved towards the first component 81 against the bias force of the spring member 83. Due to this movement, the guide protrusions 87 slide along the guide surfaces 88, which results in an axial-rotational displacement of the second component 82 relative to the first component 81. During this movement, the protrusions 85 are moved in circumferential direction relative to the bayonet structure 86 so that they are axially released from the bayonet structure 86. This state is shown in Fig. 7D. When the administration of the medicament has been completed and the piston 3 has reached its proximal position, the plunger rod 4 is retracted. Upon retraction of the plunger rod 4, the force of the spring member 83 pushes the second component 82 distally, relative to the first component 81 (see Fig. 7E). This distal movement of the second component 82, however, causes push protrusions 89 to interact with the retraction prevention members 84. This interaction causes the retraction prevention members 84 to flex outwards and thus to contact the inner surface of the container wall 11. At the same time, the retraction prevention members 84 catch the push protrusions 89 such that the second component 82 is stopped from further distal movement and from falling off the first component 81 due to the spring force. The spring force of the spring member 83 still being applied on the second component 82 maintains the outward deflection of the retraction prevention member 84 against the container wall 11. The contact between the retraction prevention member 84 of the first component 81 provides resistance / friction to prevent retraction of the piston 3. The contact between the retraction prevention member 84 and the inner container wall 11 may already provide sufficient resistance to prevent piston retraction. Alternatively, the material of the first component 81 can be highly frictional or of rubber-like material. Further alternatively, rubber-like material can be attached or over-moulded on the retraction prevention member 84 to provide sufficient friction, or increase the friction, between the first component 81 and the inner surface of the container wall 11.

[0060] An eighth embodiment, e.g., the second aspect of the present invention, is shown in Figs 12A to 12C. In this embodiment, the auto injector has a power unit 101 and a drug cassette 102. The power unit 101 has a power unit housing 103 (partially broken away in Figs. 12A to 12C), and the drug cassette has a drug cassette housing 104 (partially broken away in Figs. 12A to 12C). A needle cover 110 protrudes from the drug cassette housing 104. The power unit 101 has a drive module 105.

[0061] In this embodiment, the motor control system, e.g., the drive module 105 is configured to specify that plunger rod retraction will start only when auto injector is lifted from injection site, which also means the needle cover 110 is released. The drive module 105 comprises a motor, in particular an electric motor, for driving the plunger rod. Furthermore, drive module 105 comprises a control circuit with a processor for controlling the motor. The auto injector of this embodiment comprises a sensor 100 for sensing the position of the needle cover 110. The control circuit and the sensor 100 are mounted on a printed circuit board, PCB. The sensor 100 can be implemented as a switch implemented to detect the position of the needle cover 110 of the auto injector. By specifying an operation sequence as explained with Figs. 12A to 12C, this auto injector can prevent that piston retraction happens while needle is still inside the user's skin.

[0062] In Fig. 12A, the auto injector is shown in a state before injection. The switch 100 is initially deactivated. In Fig. 12B the needle cover 110 is shown moved into the drug cassette housing 104 of the auto injector so that the injection is activated. Here, the switch 100 is activated with the needle cover 110 being moved inwards. In Fig. 12C, the needle cover 110 is shown in its released state and the switch 100 is deactivated when the needle cover 110 is released. This is the trigger for starting the retraction of the plunger rod (not shown) by the power unit 101.

[0063] The on-body injection devices / medicament 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 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, hidradenitis 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, Behget’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,

[0064] Fabry disease, Gaucher disease), growth factor deficiencies, hormone deficiencies, coagulation disorders (e.g., hemophilia, von Willebrand disease, Factor V Leiden), and cancer.

[0065] 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.

[0066] 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.

[0067] 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-1 (GLP-1) modulators, glucose-dependent insulinotropic polypeptide (GIP) modulators, cluster of differentiation 38 (CD38) modulators, cluster of differentiation 22 (CD22) modulators, Cl 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 (TIG IT) 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 wl37 (CDwl37) 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 wl23 (CDwl23) 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, tumor-infiltrating 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-la, interferon beta-lb, peginterferon beta-la, 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.

[0068] 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.

[0069] 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.

[0070] 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.

[0071] 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, 100 U / mL Heparin Lock Flush Solution, or 5000 U / mL Heparin Lock Flush Solution.

[0072] 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 coformulated dispersion enhancers (e.g. an animal-derived, human-derived, or recombinant hyaluronidase enzyme), concentration modifiers or enhancers, stabilizers, buffers, or other excipients.

[0073] 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, mFOLFOXG, mFOLFOX7, 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.

[0074] The invention is further defined by the following clauses:

[0075] 1. An auto injector for administering a medicament, comprising: a container holder; a container (1) containing the medicament and comprising a piston (3); a plunger rod (4); and a drive module configured to move the plunger rod (4) in a proximal direction for administering the medicament and to move the plunger rod (4) in a distal direction for plunger rod retraction; and a retraction prevention structure configured to prevent retraction of the piston (3) upon retraction of the plunger rod (4).

[0076] 2. The auto injector of clause 1, wherein the retraction prevention structure is an auxiliary component (10, 30) arranged between the piston (3) and the plunger rod (4).

[0077] 3. The auto injector of clause 2, wherein the auxiliary component (10) is a compressible and radially expandable material.

[0078] 4. The auto injector of clause 3, wherein the auxiliary component (10) is a rubber-like material.

[0079] 5. The auto-injector of clause 3, wherein the auxiliary component (10) is of a material that maintains its expanded shape after being compressed.

[0080] 6. The auto injector of any one of clauses 3 to 5, wherein the auxiliary component (10) in its expanded state contacts the inner surface of the container wall (11).

[0081] 7. The auto injector of clause 2, wherein the auxiliary component (30) comprises a magnetic material. 8. The auto injector of clause 7 , further comprising one or more magnets (21, 22) interacting with the magnetic material of the auxiliary component (30) to attract and maintain the auxiliary component (30) in its proximal position.

[0082] 9. The auto injector of clause 8, wherein the one or more magnets (21, 22) are arranged at a proximal area of the container (1).

[0083] 10. The auto injector of clause 1, wherein the retraction prevention structure is a proximal area (40) of the container (1) having a larger diameter than an area (41) distal therefrom.

[0084] 11. The auto injector of clause 10, wherein the piston (3) is of a compressible material.

[0085] 12. The auto injector of clause 11, wherein the piston (3) assumes an expanded state when being pushed by the plunger rod (4) into the proximal area (40) having larger diameter.

[0086] 13. The auto injector of clause 10, 11, or 12, wherein the container wall (11) has a stepped configuration from the distal area (41) to the proximal area (40).

[0087] 14. The auto injector of clause 13, wherein the stepped configuration of the container wall (11) is configured to prevent retraction of the piston (3).

[0088] 15. The auto injector of clause 1, wherein the retraction prevention structure is formed by an intermediate portion (70) of the container (1) having a smaller diameter than an area proximal and distal therefrom.

[0089] 16. The auto injector of clause 15, wherein the intermediate portion (70) is annular in shape.

[0090] 17. The auto injector of clause 15, wherein the intermediate portion (70) is two or more separate radially inward deformations of the container wall (11), wherein the two or more inward deformations are arranged along a circular path on the container wall (11)- 18. The auto injector of clause 15, 16, or 17, wherein the intermediate portion (70) separates a proximal area (71) and a distal area (72) of the container (1) such that the proximal area (71) has an axial length to accommodate therein the piston (3) in its proximal position.

[0091] 19. The auto injector of clause 1, wherein the retraction prevention structure is a structure at the inner container wall (11) configured to provide increased friction between the inner container wall (11) and the outer circumferential surface of the piston (3).

[0092] 20. The auto injector of clause 19, wherein the retraction prevention structure is at a proximal area (51, 61) of the container (1).

[0093] 21. The auto injector of clause 19 or 20, wherein the retraction prevention structure is one or more protrusions (50, 60) at the inner container wall (11).

[0094] 22. The auto injector of clause 21, wherein the one or more protrusions (50) extend in circumferential direction.

[0095] 23. The auto injector of clause 22, wherein the protrusions (50) are spaced from each other in circumferential and or axial direction.

[0096] 24. The auto injector of clause 22, wherein the one or more protrusions (50) are annular.

[0097] 25. The auto injector of clause 19, 20, or 21, wherein the one or more protrusions (60) extend axially in proximal-distal direction.

[0098] 26. The auto injector of clause 25, wherein the protrusions (60) have the same or different lengths.

[0099] 27. The auto injector of clause 26, wherein the length of the one or more protrusions (60) is equal to or smaller than the axial length of the piston.

[0100] 28. The auto injector of clause 27, wherein the length of the one or more protrusions is at least half the axial length of the piston (3). 11 The auto injector of clause 1, wherein the retraction prevention structure is an auxiliary module (80) arranged in proximal-distal direction between the piston (3) and the plunger rod (4). The auto injector of clause 29, wherein the auxiliary module (80) comprises a first component (81) having a proximal surface portion in contact with the piston (3), a second component (82) having a distal surface portion in contact with the plunger rod (4), and an interface component (83) operately arranged between the first component (81) and the second component (82). The auto injector of clause 30, wherein the first component (81) has a generally cylindrical shape. The auto injector of clause 30 or 31, wherein the second component (82) has a generally cylindrical shape. The auto injector of clause 30, 31, or 32, wherein the second component (82) is in part received within the first component (81). The auto injector of any one of clauses 30 to 33, wherein the first component (81) and the second component (82) are mechanically connected to each other, wherein the mechanical connection is configured to prevent separation of the first component (81) from the second component (82) in distal direction and to allow displacement of the first component (81) relative to the second component (82) in proximal direction. The auto injector of any one of clauses 30 to 34, wherein the interface component (83) is a spring member. The auto injector of clause 35 insofar as dependent from clause 34, wherein the spring member is arranged to bias the second component (82) in distal direction. The auto injector of clause 34, 35, or 36, wherein the first component (81) comprises one or more retraction prevention member (84) configured to prevent retraction of the auxiliary module (80) upon being activated. The auto injector of clause 37 wherein the mechanical connection is configured to allow displacement of the second component (82) relative to the first component (81) causing activation of the one or more retraction prevention member (84). The auto injector of clause 38, wherein the mechanical connection is configured to allow displacement of the second component (82) from a first axial and rotational position to a second position being at least rotationally different from the first position. The auto injector of clause 39, wherein displacement of the second component (82) from the first position to the second position causes the mechanical connection to activate the one or more retraction prevention member (84). The auto injector of any one of clauses 37 to 40, wherein the one or more retraction prevention member (84) are flexible arms configured to be pushed radially outwards against the container wall (11). An auto injector for administering a medicament, comprising: a container holder; a displaceable needle cover (110); a container containing the medicament and comprising a piston; a plunger rod for delivery of the medicament; and a drive module configured for proximal movement of the plunger rod for administering the medicament and for distal movement of the plunger rod for plunger rod retraction; and a sensor (100) for sensing position of the needle cover; wherein the drive module is configured to initiate plunger rod retraction if the sensor senses the needle cover assuming a release position. The auto injector of clause 42, wherein the sensor (100) for sensing position of the needle cover is a switch. The auto injector of clause 43, wherein the switch is configured to be in a deactivated state prior to use of the auto injector. The auto injector of clause 43, or 44, wherein the switch is configured to be in an activated state when the needle cover is displaced upon use of the auto injector. The auto injector of clause 43, 44, or 45, wherein the switch is configured to be in a deactivated state when the needle cover is released at completion of the use of the auto injector.

Claims

Claims1. An auto injector for administering a medicament, comprising: a container holder; a container (1) containing the medicament and comprising a piston (3); a plunger rod (4); and a drive module configured to move the plunger rod (4) in a proximal direction for administering the medicament and to move the plunger rod (4) in a distal direction for plunger rod retraction; and a retraction prevention structure configured to prevent retraction of the piston (3) upon retraction of the plunger rod (4).

2. The auto injector of claim 1, wherein the retraction prevention structure is an auxiliary component (10, 30) arranged between the piston (3) and the plunger rod (4).

3. The auto injector of claim 2, wherein the auxiliary component (10) is a compressible and radially expandable material, wherein, preferably, the auxiliary component (10) in its expanded state contacts the inner surface of the container wall (11).

4. The auto injector of claim 2, wherein the auxiliary component (30) comprises a magnetic material.

5. The auto injector of claim 4, further comprising one or more magnets (21, 22) interacting with the magnetic material of the auxiliary component (30) to attract and maintain the auxiliary component (30) in its proximal position.

6. The auto injector of claim 1, wherein the retraction prevention structure is a proximal area (40) of the container (1) having a larger diameter than an area (41) distal therefrom.

7. The auto injector of claim 6, wherein the piston (3) is of a compressible material, and wherein, preferably, the piston (3) assumes an expanded state when being pushed by the plunger rod (4) into the proximal area (40) having larger diameter.

8. The auto injector of claim 1, wherein the retraction prevention structure is formed by an intermediate portion (70) of the container (1) having a smaller diameter than an area proximal and distal therefrom.

9. The auto injector of claim 8, wherein the intermediate portion (70) is annular in shape, or wherein the intermediate portion (70) is two or more separate radially inward deformations of the container wall (11), wherein the two or more inward deformations are arranged along a circular path on the container wall (11).

10. The auto injector of claim 1, wherein the retraction prevention structure is a structure at the inner container wall (11) configured to provide increased friction between the inner container wall (11) and the outer circumferential surface of the piston (3).

11. The auto injector of claim 10, wherein the retraction prevention structure is at a proximal area (51, 61) of the container (1).

12. The auto injector of claim 10 or 11, wherein the retraction prevention structure is one or more protrusions (50, 60) at the inner container wall (11).

13. The auto injector of claim 1, wherein the retraction prevention structure is an auxiliary module (80) arranged in proximal-distal direction between the piston (3) and the plunger rod (4).

14. The auto injector of claim 13, wherein the auxiliary module (80) comprises a first component (81) having a proximal surface portion in contact with the piston (3), a second component (82) having a distal surface portion in contact with the plunger rod (4), and an interface component (83) operately arranged between the first component (81) and the second component (82).

15. An auto injector for administering a medicament, comprising: a container holder; a displaceable needle cover (110); a container containing the medicament and comprising a piston; a plunger rod for delivery of the medicament; anda drive module configured for proximal movement of the plunger rod for administering the medicament and for distal movement of the plunger rod for plunger rod retraction; and a sensor (100) for sensing position of the needle cover; wherein the drive module is configured to initiate plunger rod retraction if the sensor senses the needle cover assuming a release position.

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