WO1998014211A1

WO1998014211A1 - Pharmaceutical products containing protein-tyrosine kinase inhibitors and anti-cd4 antibodies

Info

Publication number: WO1998014211A1
Application number: PCT/GB1997/002695
Authority: WO
Inventors: Ulrike Charlotte Gimsa; Nicholas Avrion Mitchison; Rodger Anthony Allen
Original assignee: Celltech Therapeutics Limited
Priority date: 1996-10-01
Filing date: 1997-10-01
Publication date: 1998-04-09
Also published as: AU4563197A; EP0946195A1

Abstract

There is disclosed a pharmaceutical product comprising a protein-tyrosine kinase p56lck inhibitor and an anti-CD4 antibody for simultaneous combined, simultaneous separate or sequential use in therapy and use of such products in medicine for instance by promotion of differentiation of Th2 cells.

Description

PHARMACEUTICAL PRODUCTS CONTAINING PROTEIN - TYROSINE KINASE INHIBITORS AND ANT1-CD4 ANTIBODIES

This invention relates to pharmaceutical products comprising a protein- tyrosine kinase inhibitor and an anti-CD4 antibody and to their use in medicine.

Although contested in detail the concept of balance between Th1 and Th2 cells in the immune system is now well established (ref. 1 - for the literature referenced herein see the list 'References' hereinafter): one subset of helper T cells produces principally one range of cytokines, while the other produces a different range (ref. 2, 3). Interferon-gamma (IFN-γ) is the most characteristic product of Th1 cells, and interleukin-4 (IL-4) of Th2 cells (ref. 2, 3). Th1 and Th2 cells both differentiate from ThO cells which produce either none or a mixed range of cytokines. It is also accepted that imbalance in favour of Th1 cells occurs in the major human autoimmune diseases, such as rheumatoid arthritis (ref. 3, 4) and multiple sclerosis (ref. 5). Agents able to restore balance are needed, as probes to test the possibility that the imbalance itself contributes to pathogenesis, and as potential therapeutic agents.

A growing list of agents has been found to drive differentiation of Th2 cells preferentially: salbutamol (ref. 6), monomethylfumarate (ref. 7), thalidomide (ref. 8, but see also ref. 9) and prostaglandin-E22 (ref. 10). Additional agents have been found able to prolong allograft survival in association with Th2 differentiation. Some of these agents have been identified as acting on antigen-presenting cells (APC), others appear to act within the responding T-cells themselves, while for the majority the target cell is uncertain. For those agents which do act within T-cells the underlying question remains open of whether they modify signal-strength from the TCR complex, or whether they act on the process of differentiation independently of this pathway.

Costimulation of T cells through the CD4 and CD28 cell-surface receptors plays a significant role in determining the extent to which Th1 or Th2 cells are produced. While the effect of blocking the latter receptor is unclear (ref. 12, 13), several experiments indicate that blocking CD4 favours Th2 differentiation (ref. 14).

Agents likely to interfere with signalling from CD4 molecules offer a promising means of modulating signal strength, as anti-CD4 antibody can drive Th2 differentiation in vitro (ref. 14) and in vivo. Treatment with this type of antibody facilitates the induction of CD4 T-cell populations able to protect against autoimmunity (ref. 15) through a mechanism suspected of involving cytokine imbalance. This form of treatment has a long history of promising results in clinical organ transplantation and more recently in rheumatoid arthritis (ref. 16) although it has not found general use. Surprisingly, CD4-/-mice show a bias away from Th2 differentiation (ref. 17) presumably reflecting unexpected selective events in the immune system as it develops in these mice.

The Src-family protein-tyrosine kinase p56^ick (abbreviated hereinafter as "lck" except where otherwise indicated) is physically associated with the cytoplasmic tail of CD4 and is the only molecule known to transmit signals from CD4 (ref. 18). Lck also regulates tyrosine phosphorylation of the T- cell receptor (TCR) -ζ chain, CD3-ε, and ZAP-70. Lck-/- mice have greatly reduced numbers of thymocytes and peripheral αβ+ T-cells (ref. 19). p59^fyⁿ (Fyn) is another member of the same family that also phosphorylates proteins of the T-cell receptor complex, although it does not bind to the CD4 molecule. The immune system of Fyn-/- mice is impaired, but to a much lesser extent than that of lck-/- mice (ref. 20).

Two recent publications describe small molecules able to block the kinase activity of lck (ref. 21 , 22). These and other selective lck inhibitors (see hereinafter) have been suggested for use in the treatment of autoimmune diseases.

We have now found that by using a lck inhibitor it is possible to promote the differentiation of Th2 cells. Unexpectedly this effect can be markedly enhanced by co-treatment of the responding T-cells with an anti-CD4 antibody, even though the antibody has little effect on the cells on its own. This synergistic effect has allowed us to develop a pharmaceutical product for use in medicine, particularly for the improved treatment or prophylaxis of autoimmune diseases. The synergistic effect of lck inhibitor and anti- CD4 antibody opens the possibility of using the antibody to sharpen the specificity of the inhibitor in vivo, thus allowing use of lower doses of the inhibitor and reducing the danger of side effects resulting from inhibition of other kinases of the same family.

Thus according to one aspect of the invention we provide a pharmaceutical product comprising a protein-tyrosine kinase p56^lck inhibitor and an anti- CD4 antibody for simultaneous combined, simultaneous separate or sequential use in therapy.

One such pharmaceutical product for use according to the invention may take the form of a pharmaceutical composition in which the lck inhibitor and the anti-CD4 antibody are formulated in admixture, optionally together with a pharmaceutically acceptable excipient, diluent, or carrier and the invention extends to such compositions. Alternatively the product for use according to the invention may take the form of a separately formulated lck inhibitor and a separately formulated anti-CD4 antibody optionally presented together for simultaneous or sequential use.

The lck inhibitor for use in any aspect of the invention may in general be any compound which inhibits the action of the protein-tyrosine kinase p56^lck. Preferably the lck inhibitor will be a selective inhibitor of p56^lck. A number of such inhibitors has been described in the art. Particular examples include quinolones (ref. 21 ) and analogues thereof; pyrazolopyrimidines (ref. 22) and analogues thereof; 1 ,2-diarylethanes and 1 ,2-diarylethenes (ref. 23) and analogues thereof; naphthalenes, quinolines and isoquinolines (ref. 24, 25) and analogues thereof; quinazolines (ref. 26) and analogues thereof; and anilinopyhmidines (ref. 27) and analogues thereof. Especially useful inhibitors include the pyrazolopyrimidines 4-Amino-5-(4-methylphenyl)-7-(t-butyl)pyrazolo[3,4-d]- pyrimidine (PP1 ) and 4-Amino-5-(4-chlorophenyl)-7-(t-butyl)pyrazolo[4,5- djpyrimidine (PP2) (ref. 22). Alternatively, a lck inhibitor for use in the invention may be obtained by conventional screening methods, for example by the use of in vitro enzyme assays (ref. 22). The anti-CD4 antibody for use in the product according to the invention may be a whole antibody or an antigen binding fragment thereof, for example a Fab or F(ab')2 fragment. The antibody may be of animal, for example mammalian origin and may be for example of murine, rat or human origin. It may be polyspecific, but is preferably monospecific for a CD4 protein, especially a human CD4 protein. In particular the antibody may preferably bind to an epitope in the 3rd extracellular and/or membrane-proximal 4th domain of human CD4 (ref. 26). The antibody will in particular be a blocking, non-stimulatory antibody. It may be a polyclonal antibody or, preferably, a monoclonal antibody. Where desired, it may be a recombinant antibody or a labelled antibody, the label being for example a reporter or effector group.

The anti-CD4 antibody may be selected or derived from known anti-CD4 antibodies, for example the antibodies OKT4, RmCD4-2 (ref. 32) or YTA3.12 (ref. 33) or obtained using conventional immunisation and/or recombinant DNA techniques. In each instance suitable antibodies may be selected by using an appropriate in vitro screen employing for example human CD4+ T cells and examining the ability of the antibody to enhance differentiation of Th2 cells in the presence of a lck inhibitor. A simple screen may be for example based on the measurement of IL-4 and IFN-γ production by human CD4+T cells in an analogous method to that described in the Example hereinafer using mouse splenocytes.

Thus, for example polyclonal antibodies may be obtained from the sera of animals immunised with a CD4 immunogen. The immunogen may be the whole CD4 protein or preferably a fragment thereof, particularly the 3rd and/or 4th extracellular domains. Well known methods may be used to obtain the immunogen either from readily available cell sources e.g. human thymocytes or CD4 gene and/or protein sequence data. Any suitable host, for example BALB/c mice where it is desired to obtain a mouse polyclonal antibody, may be injected with the immunogen, the serum collected and the antibody recovered therefrom. Monoclonal antibodies may be obtained from hybridomas derived from the spleen cells of an animal immunised as just discussed and fused to an appropriate "immortal" B-tumour cell. In each instance, any selected antibody may be recovered from either the serum or the hybridoma by making use of standard identification and purification and/or concentration techniques, for example by chromatography, using for example Protein A or by other affinity chromatography. Identification of the antibody may be by any conventional means, for example by use of one or more cell based binding assay systems utilising appropriate indicator cell lines, for example as described in International Patent Specification No. WO 91/09966.

Once a cell line, for example a hybridoma, expressing an antibody suitable for use in the invention has been obtained it is possible to clone therefrom the cDNA and to identify the variable region genes encoding the desired antibody, including the sequences encoding the CDRs. From here, other recombinant antibodies for use in to the invention may be obtained by preparing one or more replicable expression vectors containing at least the DNA sequence encoding the variable domain of the antibody heavy or light chain and optionally other DNA sequences encoding remaining portions of the heavy and/or light chains as desired, and transforming an appropriate cell line, e.g. a non-producing myeloma cell line, such as a mouse NSO line, in which production of the antibody will occur. In order to obtain efficient transcription and translation, the DNA sequence in each vector should include appropriate regulatory sequences, particularly a promoter and leader sequence operably linked to the variable domain sequence. Particular methods for producing antibodies in this way are generally well known and routinely used. For example, basic molecular biology procedures are described by Maniatis et al [Molecular Cloning, Cold Spring Harbor Laboratory, New York, 1989]; DNA sequencing can be performed as described in Sanger et al [PNAS 74, 5463, (1977)] and the Amersham International pic sequencing handbook; and site directed mutagenesis can be carried out according to the method of Kramer et al [Nucl. Acids Res. 12, 9441 , (1984)] and the Anglian Biotechnology Ltd handbook. Additionally, there are numerous publications, including patent specifications, detailing techniques suitable for the preparation of antibodies by manipulation of DNA, creation of expression vectors and transformation of appropriate cells, for example as reviewed by Mountain A and Adair, J R in Biotechnology and Genetic Engineering Reviews [ed. Tombs, M P, 1_0, Chapter 1 , 1992, Intercept, Andover, UK] and in International Patent Specification No. WO 91/09967.

Formulation of the lck inhibitor and anti-CD4 antibody for use in a product according to the invention may be carried out using conventional procedures. Each active ingredient may take any suitable form for administration to the host, for example a form for oral, parenteral or rectal administration.

Where the active ingredient is for parenteral administration, for example for intravenous, intramuscular or subcutaneous injection or infusion, it may be presented in unit dosage form, e.g. in glass ampoule or multi dose containers, e.g. glass vials. It may be formulated as a suspension, solution or emulsion in an oily or aqueous vehicle optionally containing formulatory agents such as suspending, stabilising, preserving and/or dispersing agents. Alternatively the active ingredient may be in a dry form, e.g. a powder for reconstitution before use with an appropriate sterile liquid, e.g. sterile pyrogen-free water.

For oral administration, the active ingredient may take the form of, for example, tablets, lozenges or capsules prepared by conventional means with pharmaceutically acceptable excipients such as binding agents (e.g. pregelatinised maize starch, polyvinylpyrrolidone or hydroxypropyl methylcellulose); fillers (e.g. lactose, microcrystalline cellulose or calcium hydrogen phosphate); lubricants (e.g. magnesium stearate, talc or silica); disintegrants (e.g. potato starch or sodium glycollate); or wetting agents (e.g. sodium lauryl sulphate). The tablets may be coated by methods well known in the art. Liquid preparations for oral administration may take the form of, for example, solutions, syrups or suspensions, or they may be presented as a dry product for constitution with water or other suitable vehicle before use. Such liquid preparations may be prepared by conventional means with pharmaceutically acceptable additives such as suspending agents, emulsifying agents, non-aqueous vehicles and preservatives. The preparations may also contain buffer salts, flavouring, colouring and sweetening agents as appropriate. Preparations for oral administration may be suitably formulated to give controlled release of the active compound.

For rectal administration the active ingredient may be formulated with a binding and/or lubricating agent, for example with a polymeric glycol, a gelatin, cocoa-butter or other vegetable wax or fat.

The active ingredient(s) may, if desired, be presented in a pack or dispenser device which may contain one or more unit dosage forms containing each active ingredient. The pack or dispensing device may be accompanied by instructions for administration.

In the product according to the invention the anti-CD4 antibody is likely to be unsuitable for oral administration and it is preferably used in a formulation for parenteral administration using for example one of the approaches described above.

In one of the aspects of the invention described above the product comprises a lck inhibitor and an anti-CD4 antibody in admixture and according to a further aspect of the invention we therefore provide the use of a lck inhibitor and an anti-CD4 antibody in the manufacture of a pharmaceutical product for simultaneous combined, simultaneous separate or sequential use in therapy. Thus for example the lck inhibitor and the anti-CD4 antibody may be mixed together and other ingredients, e.g. a pharmaceutically acceptable excipient, diluent or carrier, also mixed in as required, to yield for example a product formulated for oral, parenteral or rectal administration as described previously.

A particular therapeutic use to which the products according to the invention may be put is in the treatment or prophylaxis of autoimmune diseases. Particular diseases include rheumatoid arthritis, multiple sclerosis and systemic lupus erythematosus. The products according to the invention will thus contain active ingredients at a therapeutically effective dose and in a further aspect of the invention we provide a method of treatment or prophylaxis of a human or animal subject suffering or at risk of suffering from an autoimmune disease the method comprising administering to the subject a pharmaceutical product comprising an effective amount of a lck inhibitor and an effective amount of an anti-CD4 antibody.

The doses at which the lck inhibitor and anti-CD4 antibody will be administered will depend for example on variables such as the age and condition of the patient and the route of administration. In general the active ingredients will be used at doses generally recognised to be effective for the class of compound involved. Thus, for example where the anti-CD4 antibody may be used at a dose between 0.05 - 25mg/kg, preferably 0.1 - 10mg/kg body weight per single dose. The lck inhibitor for example may be used at doses within the range 100ng/kg to 100mg/kg e.g. around 0.01 mg/kg to 40mg/kg body weight for oral administration and from around 10ng/kg to 50mg/kg body weight for parenteral administration. Advantageously, however, due to the enhanced activity of the combination product, the lck inhibitor may be used at the lower ends of these dose ranges thus minimising any potential side effects of the compound. In each case, the doses may be administered singly one or more times a day or continuously during a day up to a maximum effective or tolerated total dose.

The following Example illustrates the invention, in particular the ability of a lck inhibitor and an anti-CD4 antibody to synergistically promote the differentiation of Th2 cells.

EXAMPLE

The Experimental System used here to Detect Activity Favouring

Differentiation of Th2 Cells The mouse line DO 10 expresses a transgenic αβ T-cell receptor (TCR) able to recognise the ovalbumin peptide 323-339 (ref. 29). Upon stimulation in vitro by the ovalbumin peptide these cells produce IFN-γ and IL-4, the cytokines characteristic of Th1 and Th2 cells. This system has been widely used to investigate conditions which favour differentiation of one or other cell type (ref. 30, 31 ). Experimental Design Used Here

A lck inhibitor was added to cultures of spleen cells derived from the TCR- transgenic mice referred to above, while these cells were undergoing stimulation with ovalbumin peptide. The purpose of this experiment was to determine whether the inhibitor would favour differentiation of Th2 cells, as judged by the production of IL-4 and inhibition of the production of interferon-gamma. In addition, an anti-CD4 monoclonal antibody was added into some of the cultures, to determine whether this treatment would enhance the Th2-favouring effect of the inhibitor.

Transgenic Mouse Cell Assay Materials and Methods

Spienocytes of DO 10 mice (<12 weeks of age) were isolated by Ficoll (Histopaque-1083, Sigma, Deisenhofen, Germany) gradient centrifugation and taken into culture at a concentration of 2 x 10⁶ cells/ml in complete medium (RPMI 1640-Medium; Gibco, BRL, Life Technologies, Eggenstein, Germany; supplemented with 10% FCS, Sigma, Deisenhofen, Germany, 2 mM L-glutamine: Gibco, BRL, Life Technologies, Eggenstein, Germany; 50 μM mercaptoethanol and 100 U/ml antibiotic-antimycotic; Gibco, BRL, Life Technologies, Eggenstein, Germany) together with 0.3μM ovalbumin peptide 323-339 (TIB Molbiol, Berlin, Germany). As a control for Th2 differentiation recombinant mouse IL-4 (BioSource International, Camarillo, CA, USA) was added to one well to a concentration of 200 U/ml, and as a control for Th1 differentiation recombinant mouse IL-12 (Hoffmann-La Roche, Nutley, NJ, USA) was added to another well to a concentration of 1 ng/ml. Another well contained cells and ova-peptide alone as a further control.

In the other wells tyrosine kinase inhibitors were added, and/or monoclonal anti-CD4 antibodies. These were tested alone or in combination in varying concentrations. The inhibitors, dissolved in dimethylsulphoxide (DMSO) were added with or without antibodies so that the final DMSO concentration was 0.1 %

At day 4 cells were split and recombinant IL-2 (100 U/ml, EuroCetus, Ratingen, Germany) was added. At day 7 cells were washed and a 0.5 x

10⁶ cells/ml were restimulated with 0.3 μM ova-peptide together with 1 x 10⁶ cells/ml antigen-presenting cells (APC). APC were splenocytes from BALB/c mice. Spleens were homogenised and erythrocytes lysed with 0.83% NH4CI for 5 min at room temperature, washed and irradiated with 26 Gy. At 48 hours later the culture supernatants were tested in ELISA (DuoSeT mouse IFN-γand DuoSeT mouse IL-4, Genzyme, Cambridge, MA USA) for their levels of IFN-γ and IL-4.

Data Analysis

For statistical analysis, the level of IL-4 detected in the supernatant of cells treated only with ova-peptide was taken as the minimum produced. The maximum was the mean level from cells treated with the IL-4-inducing drug at concentrations of 0.6-1 μM, i.e. at the plateau of the dose-response curve shown below in Figure 1. Data were then calculated as follows: observed level - minimum level

% maximum IL-4 production = x 100 maximum level - minimum level

A polynomial curve was fitted to data obtained in this way, and the intercept with half-maximum IL-4 production found, as shown in Figure 1.

Lck Inhibitors

4-Amino-5-(4-methylphenyl)-7-(t-butyl)pyrazolo[3,4-d]pyrimidine (PP1 ) and 4-Amino-5-(4-chlorophenyl)-7-(t-butyl)pyrazolo[4,5-d]pyrimidine (PP2).

Antibodies

Rat-anti-mouse anti-CD4 antibodies were tested: RmCD4.2 (lgG2b) and RmCD4.4 (lgG2a) (ref. 34) from S. Thierfelder (GSF-Forschungszentrum fur Umwelt und Gesundheit GmbH, Munich); YTA3.12 (lgG2b), YTS177.9 (lgG2a) and YTS191.1 (lgG2b) from H. Waldmann (Oxford University); and H129.19 (lgG2a) from M. Pierres (CNRS/INSERM, Marseille). The mouse anti-CD4 antibody GK1.5 (lgG2b) from F. Fitch (Chicago) was also tested.

CD4 Binding Assays and FACS Analysis 0.5x 10⁵ lymph node cells of BALB/c mice were incubated with blocking anti-CD4 antibodies at a concentration of 10 μg/ml in PBS/0.5% bovine serum albumin /0.01 % NaNβ on ice for 30 min. Biotinylated (labelling kit from Boehringer Mannheim, Germany) anti-CD4 antibodies YTS191 .1 , YTA3.12 or RmCD4.2 (staining antibodies) were added and incubated for a further 30 min on ice. As controls, cells were incubated with blocking or staining antibodies alone. Cells were washed and then incubated with streptavidin-FITC (Dako Diagnostika, Hamburg, Germany) for 30min on ice. After washing cells, CD4 staining was analysed on a FACScan™ flow cytometer (Becton Dickinson, San Jose, USA).

Results Increased IL-4 production and reduced IFN-γ production in presence of PP1 and PP2

The lck inhibitor PP2 significantly enhanced IL-4 production at concentrations of 400 nM and above (Figure 1 ). Above 1000nM the effect is more pronounced, but cell proliferation at 10 μM PP2 was reduced by up to 50% (data not shown). Over the one-week culture period cells proliferated at the same rate as untreated cells only at concentrations of PP2 below 1000nM (data not shown). As shown in Table 1 , individual mice varied markedly in the maximum level of IL-4 production that could be elicited with the inhibitor, unrelatedly to the level obtained by adding IL-4 itself at the beginning of the cultures. Nevertheless consistent values were obtained for the concentration of inhibitor needed to obtain a half- maximum effect, as shown in Table 1.

IFN-γ production was reduced at PP2 concentrations above 400nM.

PP1 and PP2 synergise with anti-CD4 antibodies

The anti CD4 antibody RmCD4.2 had a small suppressive effect on IL-4 and IFN-γ production when applied alone, although when used at lower concentrations it had a slight enhancing effect on IL-4 production, in line with work in the rat cited above (ref. 14). In combination with PP2 significantly more IL-4 was produced than by PP2 alone while IFN-γ production was reduced (Figure 2).

In a repeat of the above experiments using RmCD4.2 and other antibodies with the lck inhhibiotrs PP1 or PP2 a combination of RmCD4.2 or YTA3.12 and PP1 or PP2 produced significantly more IL-4 than either lck inhibitor alone even though each antibody had little effect on its own (see Figure 3). The anti CD4 antibodies RmCD4.4, GK1 .5, H129.19, YTS177.9, and YTS191.1 did not show this effect.

Binding Experiments

Binding experiments revealed that RmCD4.2 and YTA3.12 bind to overlapping epitopes not recognised by the other anti-CD4 antibodies (Table 2). The overlap is incomplete, since YTA3.12 completely blocks staining with RmCD4.2 while RmCD4.2 allows weak staining with YTA3.12. YTA3.12 is known to bind to the membrane-proximal domains 3/4 of CD4, with GK1 .5, YTS191 .1 and H129.19 binding to the outer domain 1 (ref. 35). The data suggests that RmCD4 also binds to domains 3/4, while YTS177.9 and RmCD4.4 bind to domain 1 . Thus binding to the membrane proximal domains of CD4, appears to be important for obtaining a Th2 shift in the system used here.

Table 1

Variation in the assay for potency of lck-blocking drugs in driving

IL-4 production by TCR-transgenic CD4 T cells in vitro.

pg/ml IL-4 released nM drug concentration needed for half max IL-4 release min max Th2 control¹

PP2

Mouse pair 1 1030 2560 5850 440

Mouse pair 1 960 1430 5820 305 (repeat)

Mouse pair 2 4600 6460 7900 340

PP1

Mouse pair 3 1200 2250 4350 255

¹ with IL-4 added in primary culture.

NOTE: mouse pair 2 is evidently predisposed to produce IL-4 Table 2

Analysis of binding of anti-CD4 antibodies to different epitopes of the CD4 molecule. Each anti-CD4 antibody was used to block staining of one of three biotinylated antibodies. Staining was analysed by FACS. Blocking of staining indicates binding to the same epitope. Representative data of 2 experiments.

+++ complete blocking: < 10% of unblocked stain ++ strong blocking: 10-25% of unblocked stain no blocking: >95% of unblocked stain References

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Claims

1. A pharmaceutical product comprising a protein-tyrosine kinase p56^lck inhibitor and an anti-CD4 antibody for simultaneous combined, simultaneous separate or sequential use in therapy.

2. A pharmaceutical product according to Claim 1 wherein the p56^lck inhibitor and the anti-CD4 antibody are formulated in admixture, optionally together with a pharmaceutically acceptable excipient, diluent or carrier for simultaneous comhbined use in therapy.

3. A pharmaceutical product according to Claim 1 or Claim 2 wherein the anti-CD4 anitbody is a blocking, non-stimulatory antibody.

4. A pharmaceutical product according to Claim 3 wherein the anti-CD4 antibody binds to an epitope in the 3rd extracellular and/or 4th domain of human CD4.

5. A pharmaceutical product according to anyu one of Claim 1 to Claim 4 for use in the prophylaxis or treatment of an autoimmune disease.

6. The use of a protein-tyrosine kinase p56^lck inhibitor and an anti-CD4 antibody in the manufacture of a pharmaceutical product according to any one of Claim 1 to Claim 5.

7. A method of treatment or prophylaxis of a human or animal subject suffering or at risk of suffering from an autoimmune disease the method comprising adminsitering to the subject a pharmaceutical product comprising an effective amount of a protein-tyrosine kinase p56^lck inhibitor and an effective amount of an anti-CD4 antibody.