Dual specificity antibody fusions

1. A nucleic acid molecule encoding a dual specificity antibody fusion protein comprising an antibody Fab fragment or an antibody Fab′ fragment with specificity for an antigen of interest, the fragment being fused to two single domain antibodies that have specificity for serum albumin;

wherein one single domain antibody is fused to the C-terminus of the light chain of the Fab fragment or the Fab′ fragment and the other single domain antibody is fused to a C-terminus of a heavy chain of the Fab fragment or the Fab′ fragment; and

wherein one single domain antibody is a VH domain comprising the sequence given in SEQ ID NO:56 for CDR-H1, the sequence given in SEQ ID NO:57 for CDR-H2 and the sequence given in SEQ ID NO:58 for CDR-H3, and the other single domain antibody is a VL domain comprising the sequence given in SEQ ID NO:59 for CDR-L1, the sequence given in SEQ ID NO:60 for CDR-L2 and the sequence given in SEQ ID NO:61 for CDR-L3, wherein the VH domain is fused to the C-terminus of the heavy chain of the Fab fragment or the Fab′ fragment and the VL domain is fused to the C-terminus of the light chain of the Fab fragment or the Fab′ fragment.

2. The nucleic acid molecule of claim 1 , wherein the nucleic acid molecule is cDNA.

3. An expression vector comprising the nucleic acid molecule of claim 1 .

4. A recombinant host cell comprising the expression vector of claim 3 .

5. The nucleic acid molecule of claim 1 , wherein each single domain antibody is humanised.

6. The nucleic acid molecule of claim 1 , wherein the Fab or Fab′ of the dual specificity antibody fusion protein is fully human or humanised.

7. The nucleic acid molecule of claim 1 , wherein each single domain antibody fused to the antibody Fab or Fab′ fragment is fused via a linker of the amino acid sequence set forth in any one of SEQ ID NOs:1, 2, 3, or 45.

8. The nucleic acid molecule of claim 1 , wherein the VH domain is linked to the C-terminus of the heavy chain of the Fab or Fab′ fragment via a linker having the amino acid sequence set forth in SEQ ID NOs:2 or 45 and the VL domain is linked to the C-terminus of the light chain of the Fab or Fab′ fragment via a linker having the amino acid sequence set forth in SEQ ID NOs:1 or 45.

9. The nucleic acid molecule of claim 1 , wherein the serum albumin is human serum albumin.

10. A pharmaceutical composition comprising the dual specificity antibody fusion protein encoded by the nucleic acid of claim 1 .

11. The pharmaceutical composition of claim 10 , wherein the composition is for the treatment of a disease or disorder;

wherein the disease or disorder is an inflammatory disease or disorder, an immune disease or disorder, a fibrotic disorder and/or a cancer;

wherein the inflammatory disease or disorder and/or the immune disease or disorder comprise rheumatoid arthritis, psoriatic arthritis, still's disease, Muckle Wells disease, psoriasis, Crohn's disease, ulcerative colitis, SLE (Systemic Lupus Erythematosus), asthma, allergic rhinitis, atopic dermatitis, multiple sclerosis, vasculitis, Type I diabetes mellitus, transplantation and graft-versus-host disease;

wherein the fibrotic disorder comprises idiopathic pulmonary fibrosis (IPF), systemic sclerosis (or scleroderma), kidney fibrosis, diabetic nephropathy, IgA nephropathy, hypertension, end-stage renal disease, peritoneal fibrosis (continuous ambulatory peritoneal dialysis), liver cirrhosis, age-related macular degeneration (ARMD), retinopathy, cardiac reactive fibrosis, scarring, keloids, burns, skin ulcers, angioplasty, coronary bypass surgery, arthroplasty and cataract surgery; and

wherein the cancer comprises (i) a malignant new growth that arises from epithelium, found in skin or the lining of breast, ovary, prostate, lung, kidney, pancreas, stomach, bladder or bowel and/or (ii) bone, liver, lung or brain cancer.