TECHNICAL FIELD

The present invention relates to methods for the treatment of IL-1 -driven and

autoinflammatory diseases by the continuous infusion of an IL-1 inhibitor, and more specifically, the IL-1 receptor antagonist (IL-lra) anakinra. The methods are useful in therapy, particularly for acute and chronic inflammatory diseases and diseases triggered by host- derived danger signals and for control of disease flares in recurring inflammatory syndromes.

BACKGROUND ART

The autoinflammatory diseases are a collection of clinical syndromes characterized by bouts of fever, rash, arthropathy and arthritis, serum amyloidosis and other manifestations of inflammation, which are apparently unprovoked (Masters SL et al., 2009). The distinction between autoinflammatory and autoimmune disease is that there is no pivotal role for components of the adaptive immune system in autoinflammation. However, components of the innate immune system such as myeloid cells, and various cytokines and chemokines, often including interleukin-1 (IL-1), are central in the pathogenesis of the autoinflammatory syndromes.

The family of autoinflammatory diseases is burgeoning and comprises hereditary recurrent fever disorders (often, but not always, where components of the molecular structure called the inflammasome, responsible for the release of inflammatory factors such as IL-1, or proteins which regulate it, are mutated), such as cryopyrin-associated periodic syndromes (CAPS), hyperimmunoglobulin D syndrome (HIDS), familial Mediterranean fever (FMF) and TNF receptor associated periodic syndrome (TRAPS), idiopathic fever syndromes such as Adult Onset Still's disease (AOSD), Schnitzler syndrome and systemic onset juvenile idiopathic arthritis (SoJIA), pyogenic disorders such as pyogenic arthritis with pyoderma gangrenosum and acne (PAPA) syndrome, metabolic disorders including gout, atherosclerosis and type 2 diabetes mellitus, vasculitis, specifically Behcets disease, and autoinflammatory disorders of the musculoskeletal system such as deficiency of IL-1 receptor antagonist (DIRA) (Kastner et al, 2010). Whilst the clinical manifestations can largely be viewed as a common denominator in all these diseases, the molecular pathologies behind them differ. For a large number of them however, the production of the inflammatory cytokine IL-1 and/or concentrations of IL- 1 are elevated. This is seen in CAPS, FMF, SoJIA, AOSD, Schnitzler syndrome, DIRA and Behcets disease. Furthermore, for others, the tissue concentrations of IL-1 are elevated, such as in gout and pseudogout, atherosclerosis and type 2 diabetes.

The overproduction of IL-1 can be due to different reasons, including genetic mutation in components of the inflammasome (the NLRP3 gene in CAPS), genetic mutation in genes which regulate the inflammasome (such as the MEFV gene in FMF or the PSTPIP1 gene in PAPA) (Lachmann & Hawkins, 2009), activation of the inflammasome by host-derived danger signals such as uric acid crystals in gout (Martinon et al, 2006), calcium

pyrophosphate in pseudogout (Martinon et al, 2006), cholesterol crystals in atherosclerosis (Duewell et al, 2010), and for unknown reasons as in SoJIA, AOSD and type 2 diabetes mellitus.

For those syndromes where a role for IL-1 in the pathology of the disease has been established, the clinical manifestations of the disease can rapidly be alleviated by treatment with anti-IL-1 medicines. One such medicine is Kineret ^® , whose active component, anakinra, is a recombinant version of the naturally occurring IL-1 receptor antagonist (IL-lra). The nucleotide and amino acid sequences of human IL-lra are shown as SEQ ID NO: 1 and 2, respectively. In SEQ ID NO: 2, positions 1-25 represent the signal peptide, while positions 26-177 represent the mature polypeptide.

Recombinant anakinra is produced in E. coli, is unglycosylated and carries an N-terminal methionine residue (Schreuder et al., 1995). When administered to animals of different species, anakinra displays short biological half lives (in vivo half lives in rodents are under an hour whereas terminal half life in humans is 4-6 hours) (Kineret Anakinra Drug Approval Package, Pharmacology review, available at

http://www.accessdata.fda.gov/dmgsatfda_docs/nda/2001/103 950-0_Kineret.cfm; Galea et al, 2010; Kineret Prescribing Information, available at

http://www.kineretrx.com/professional/pi.jsp). This relatively disadvantageous short half life of the molecule means that it must be administered once daily in the treatment of human subjects with rheumatoid arthritis. Under certain circumstances, when continuous infusion of pharmaceuticals is required, due to the medical condition being treated, the type of medicine being used or other reasons, continuous treatment is achieved through the use of an infusion pump. Treatment with infusion pumps can be advantageous under certain circumstances. For example, infusion pumps allow the treatment of patients with small volumes of pharmaceuticals that would be impracticable manually. They also allow treatments with irregular administration regimens, such as at irregular time periods or with varying volumes of medicine. Administration of pharmaceuticals via infusion pumps is most often performed by direct intravenous administration although treatment via other routes, including subcutaneously, arterially or epidurally is also applied. Small volume pumps with inbuilt computer-mediated regulation are commonly used for treatment of diseases with small volumes of biological drugs, such as insulin for the treatment of diabetes, amongst others.

BRIEF DESCRIPTION OF THE DRAWINGS

Figure 1 : Experimental design for subcutaneous bolus dosing of mice with anakinra and subsequent challenge with MSU crystals.

Figure 2: Time curve of anti- inflammatory effects of anakinra in mice. C57bl/6 mice were treated with 10 mg/kg anakinra at time zero according to the experimental design shown in Figure 1. MSU crystals were injected into the peritoneal cavity at the indicated times after anakinra and neutrophil influx (upper panel) and serum IL-6 concentration (lower panel) were measured six hours later. Each symbol represents the data from individual animals. Asterisks indicate statistically-significant differences in results between groups: ** p<0.01; *** p<0.005.

Figure 3 : Experimental design for subcutaneous minipump continuous infusion administration of mice with anakinra and subsequent challenge with MSU crystals.

Figure 4: Anti- inflammatory effects of increasing concentration of anakinra delivered via osmotic minipump subcutaneously. C57bl/6 mice were treated with increasing concentrations of anakinra at time zero according to the experimental design shown in Figure 3. MSU crystals were injected into the peritoneal cavity 72 hours after minipumps were implanted, and neutrophil influx (upper panel) and serum IL-6 concentration (lower panel) were measured six hours later. Each symbol represents the data from individual animals. Asterisks indicate statistically-significant differences in results between groups: *** p<0.005

Figure 5: Comparison of dose effect relationships of anakinra when administered by bolus dosing (upper panel) or continuous infusion (lower panel) on inflammation (neutrophil influx) Solid lines are fits of the data to a 4 parameter equation from which the IC ₅₀ for the inhibitory effect was determined. IC ₅₀ for bolus dosing (upper panel) was 1.9 mg/kg-day, whilst for continuous infusion, the IC ₅₀ was 1 mg/kg-day.

DISCLOSURE OF THE INVENTION

It has surprisingly been found that continuous infusion of anakinra is an effective method for the administration of the drug for the treatment of inflammatory diseases. The problems of the short biological half life of anakinra are avoided and therapeutic benefit is sustained.

Surprisingly, anakinra demonstrates enhanced efficacy when administered as a continuous subcutaneous infusion. Anti-inflammatory effects were observed at the lowest dose tested which was not the case for when administered by bolus dosing. Furthermore, the IC ₅₀ was halved when anakinra was infused continuously. This was not expected because the inflammatory response observed in this experimental setting was the same regardless of whether anakinra was bolus dosed or infused. Thus the greater efficacy of anakinra was not due to a milder induction of the inflammatory phenotype by the MSU inflammogen. The data therefore indicate that continuous infusion of anakinra will be an effective therapy for inflammatory diseases, allowing lower doses to be used than is the case in current clinical practice. This will also be an effective means to contain and suppress disease flares in diseases which are characterized by periodic paroxysms of disease activity.

Consequently, in a first aspect the invention provides a method for the treatment or prevention of an IL-1 mediated disease which comprises administering by continuous subcutaneous infusion to a mammal, including man, in need of such treatment an effective amount of an IL- 1 inhibitor. The term "subcutaneous infusion" is well known in the art and refers to the controlled parenteral delivery of a pharmaceutically active compound to the subcutaneous tissue

(hypodermis) of a patient.

The term "continuous subcutaneous infusion" means that the said delivery of a

pharmaceutically active compound takes place for an extended period of time. For instance, the compound can be infused without interruption for a period of at least 3 days, for at least 7 days, for at least one month, etc., and for the period during which the medical need persists. Consequently, if necessary the continuous infusion can be permanent, i.e. essentially remain for the patient's life.

Alternatively, the continuous infusion may be performed two or more times (i.e., for two or more cycles), with intervening rest periods. Each cycle may be the same or different. For example, if there are two cycles, they may, independently, have the same or different duration, the same or different dosage, etc. In one embodiment, the prolonged continuous infusion is performed for two or more cycles, for example from 2 to 3 cycles, from 2 to 4 cycles, from 2 to 5 cycles, etc., with intervening rest periods. Further, "repeated cycles" of treatment can also mean that treatment is repeated whenever appropriate or necessary, e.g. at the start of a disease flare. Consequently, in such a case the rest periods may be the periods between the said disease flares.

Continuous infusion is generally performed with medical devices such as infusion pumps, which are well known to the skilled person. A pump delivering the IL-1 inhibitor into the body may be implanted in the patient's body. Alternatively, the patient may wear a pump externally, being attached to the patient's body via catheter, needle, or some other connective means. Any pump that is suitable for the delivery of pharmaceuticals to a patient may be used. For long-term (e.g. permanent) treatment, pump renewal should not be necessary more frequent than once a week. Suitable devices which include (a) an ambulatory battery-powered pump; (b) a syringe and needle/catheter; and (c) a reservoir to hold the drug, are commercially available.

The term "IL-1 inhibitor" as used throughout this specification refers to molecules that decrease the bioactivity of IL-la, IL-Ιβ, or IL-1 receptor type I (IL-1 RI), whether by direct or indirect interaction with IL-1 a, IL-Ιβ, IL-1 RI, IL-1 receptor accessory protein (IL-1 RacP), interleukin-1 converting enzyme (ICE), with proteins that mediate signaling through a receptor for IL-1 a or IL-Ιβ, with proteins controlling the expression or release of IL-1 a, IL- 1β, IL-1 RI or IL-1 RII. Inhibition of IL-1 may result from a number of mechanisms, including down- regulation of IL-1 transcription, expression, or release from cells that produce IL- 1; binding of free IL-1; interference with binding of IL-1 to its receptor;

interference with formation of the IL-1 receptor complex (i.e., association of the IL-1 receptor type I with IL-1 RacP); and interference with modulation of IL-1 signaling after binding to its receptor. Thus, the term "IL-1 inhibitor" includes, but is not limited to, IL-Ιβ inhibitors and IL-1 receptor antagonists (IL- Ira), such as anakinra (Kineret ^® ) and antibodies to IL-1 RI.

Those skilled in the art understand that many combinations of deletions, insertions, inversions and substitutions can be made within the amino acid sequences of protein IL-1 inhibitors such as anakinra, provided that the resulting molecule ("the anakinra variant") is biologically active, e.g. possesses the ability to inhibit IL-1. Particular anakinra variants are described in e.g. U.S. Patent Nos. 5,075,222; 6,858,409 and 6,599,873. The term "anakinra" further includes modified anakinra and fusion proteins comprising anakinra. Anakinra can be formatted to have a larger hydrodynamic size, for example, by attachment of a

polyalkyleneglycol group (e.g. poly ethylenegly col (PEG) group), serum albumin, transferrin, transferrin receptor or at least the transferrin-binding portion thereof, an antibody Fc region, or by conjugation to an antibody domain.

Preferably, the said IL-1 inhibitor is administered in a dose from about 0.1 to about 10 mg/kg per day, preferably from 0.1 to 1.0 mg/kg per day, such as from 0.1 to 0.9 mg/kg per day, from 0.1 to 0.5 mg/kg per day, from 0.1 to 0.25 mg/kg per day, or about 0.1 mg/kg per day. A preferred dosage for the treatment of IL-1 mediated diseases should produce blood anakinra concentrations between 1 and 1000 ng/ml. Accordingly, it is preferred that, initially, doses are administered to bring the circulating levels of anakinra above 5 ng per ml of plasma.

A disease or medical condition is considered to be an "IL-1 mediated disease" if the spontaneous or experimental disease or medical condition is associated with elevated levels of IL-1 in bodily fluids or tissue or if cells or tissues taken from the body produce elevated levels of IL-1 in culture. In many cases, such interleukin-1 mediated diseases are also recognized by the following additional two conditions: (1) pathological findings associated with the disease or medical condition can be mimicked experimentally in animals by the administration of IL- 1; and (2) the pathology induced in experimental animal models of the disease or medical condition can be inhibited or abolished by treatment with agents which inhibit the action of IL-1. In most interleukin-1 mediated diseases at least two of the three conditions are met, and in many interleukin-1 mediated diseases all three conditions are met.

The IL-1 mediated disease is preferably an autoinflammatory disease. The term

"autoinflammatory diseases" refers to a group of disorders characterized by unexplained recurrent attacks of inflammation without any evidence that this process is related to auto- antigen exposure. Autoinflammatory diseases may also have a hereditary component usually associated with a gene mutation.

Preferably, the said autoinflammatory disease is selected from the group consisting of

• Type 1 diabetes mellitus;

• Type 2 diabetes mellitus;

• Atherosclerosis;

• TNF Receptor-Associated Periodic Syndrome (TRAPS);

• Familial Mediterranean Fever (FMF);

• Hyper-IgD Syndrome (HIDS);

• Familial Cold Associated Syndrome (FCAS);

• Muckle Wells Syndrome (MWS);

• Neonatal Onset Multi-Inflammatory Disorder/Chronic Infantile Neurological

Cutaneous and Articular syndrome (NOMID/CINCA);

• Schnitzler's Disease;

• Adult Onset Still's Disease (AOSD);

• Periodic Fevers with Aphthous Stomatitis, Pharyngitis, and Adenitis (PFAPA);

• Pyogenic sterile Arthritis, Pyoderma gangrenosum, and Acne syndrome (PAPA);

• Gout/pseudogout;

• Chronic Recurrent Multifocal Osteomyelitis (CRMO);

• Recurrent pericarditis; and

• Systemic Onset Juvenile Idiopathic Arthritis (SoJIA). In a further aspect, the method of the invention for the treatment or prevention of an IL-1 mediated disease, which disease involves a host-derived danger signal (also referred to as danger-associated molecular patterns (DAMPS)). The term "host-derived danger signal" means a molecule which initiates and perpetuates an immune response as part of a noninfectious inflammatory response.

Examples of host-derived danger signals include both protein molecules, such as heat shock proteins and serum amyloid A (SAA) as well as non-protein molecules such as crystals of uric acid or cholesterol, and heparin sulphate or DNA.

In yet another aspect, the method of the invention for the treatment or prevention of an IL-1 mediated disease, includes the control of disease flares in recurring inflammatory syndromes. A "disease flare" means a transient rise in severity of the manifestations of a disease. The said method for controlling diseases flares comprises administering by continuous infusion to a mammal, including man, in need of such treatment an effective amount of an IL-1 inhibitor.

In a further aspect the invention provides an IL-1 inhibitor for use in therapy, in particular for use in the treatment or prevention of an IL-1 mediated disease. The said use is characterized in that the said IL-1 inhibitor is administered by continuous subcutaneous infusion to a mammal, including man, in need of such treatment.

In yet another aspect, the invention provides a pharmaceutical composition comprising an IL- 1 inhibitor, characterized in that the said composition is adapted for continuous subcutaneous infusion. Pharmaceutical compositions comprising IL-1 inhibitors are well known in the art. For instance, pharmaceutical compositions comprising anakinra are known from WO

94/06457; WO 97/28828 and WO 98/24477.

EXAMPLES

EXAMPLE 1 (for comparison): Bolus treatment of mice with anakinra.

The duration of the biological effect of anakinra administered as a bolus dose subcutaneously to mice, was measured. After treatment with anakinra, mice were challenged by intraperitoneal injection of the inflammogen, uric acid crystals, at different times, and markers of inflammation (neutrophil influx and serum IL-6 concentrations) were measured six hours later. The experimental design is shown in Figure 1. Polymorphonuclear cells which had migrated into the peritoneal cavity were counted in samples of intraperitoneal fluid. 20 μΐ samples were diluted with 380 μΐ Turks reagent (1% crystal violet in diluted acetic acid) and counted by phase contrast microscopy (Mishell et al, 1980). Serum IL-6 concentrations were measured with the use of a commercially available ELISA assay (Pierce/Thermo Scientific) according to the manufacturer's instructions (http://www.piercenet.com/files/1362as8.pdf). Briefly, 50 μΐ sample was added to the wells of an ELISA plate pre-coated with an anti-IL-6 antibody. After two hours' incubation, the plate was washed and wells incubated with a biotinylated antibody. After one hour's incubation and washing, streptavidin-complexed horse radish peroxidase (HRP) reagent was added and HRP-mediated conversion of a colorimetric substrate was measured. Results were compared with a standard curve allowing the concentration of IL-6 in the sample to be calculated. The data, shown in Figure 2, indicate that anakinra exerts an anti- inflammatory effect in MSU-challenged mice when administered for as long as two hours before the inflammogen challenge. However, when inflammogen is administered 12 hours after anakinra, no anti- inflammatory effect of anakinra remains, either on polymorphonuclear cell influx or evoked IL-6 responses. Thus the therapeutic effect of anakinra in mice is lost between 2 and 12 hours after dosing.

EXAMPLE 2: Continuous subcutaneous infusion of anakinra in mice.

The therapeutic efficacy of anakinra when administered as a continuous subcutaneous infusion by osmotic mini-pump was examined according to the experimental protocol outlined in Figure 3. Mini-pumps (www.alzet.com) were implanted in c57/bl6 mice on day 1, delivering anakinra subcutaneous ly at constant rates. Three days later, mice were treated with intraperitoneal injection of the inflammogen, MSU crystals, and markers of inflammation (neutrophil influx into the intraperitoneal cavity and serum IL-6) were measured 6 hours later, as described for Example 1. The data showed that continuous infusion of anakinra was able to inhibit inflammation in a dose-dependent fashion (Figure 4).

Surprisingly, when compared to the dose-efficacy of anakinra administered as a subcutaneous bolus dose, reductions in inflammation were observed at significantly lower doses of anakinra when provided via mini-pump (0.1 mg/kg per day, versus 1 mg/kg per day) (Figure 5).

Furthermore, the IC ₅₀ for anakinra when dosed by continuous infusion was half that for bolus dosing (1.0 mg/kg per day, versus 1.9 mg/kg per day). Thus anakinra is unexpectedly a more effective anti- inflammatory agent when administered to animals via continuous infusion rather than bolus dosing.

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