Bispecific antibodies

#This application is the National Stage of International Patent Application No. PCT/JP2011/076486, filed on Nov. 17, 2011, which claims the benefit of Japanese Patent Application Serial No. 2010-257022, filed on Nov. 17, 2010.

#The present invention relates to multispecific antigen-binding molecules that functionally substitute for blood coagulation factor VIII, a cofactor that enhances enzymatic reactions, and pharmaceutical compositions comprising such a molecule as an active ingredient.

#Hemophilia A is a bleeding abnormality caused by a hereditary decrease or deficiency of blood coagulation factor VIII (F.VIII) function. Hemophilia A patients are generally administered with an F.VIII formulation for the bleeding (on-demand administration). In recent years, F.VIII formulations are also administered prophylactically to prevent bleeding events (preventive administration; Non-patent Documents 1 and 2). The half-life of F.VIII formulations in blood is approximately 12 to 16 hours. Therefore, for continuous prevention, F.VIII formulations are administered to patients three times a week (Non-patent Documents 3 and 4). In on-demand administrations, F.VIII formulations are also additionally administered when necessary at regular intervals to prevent rebleeding. In addition, the administration of F.VIII formulations is done intravenously. Therefore, there has been a strong need for pharmaceutical agents with a lesser burden than F.VIII formulations.

#FIG. 1 describes the F.Xase inhibitory action.

#(a) F.VIIIa forms a complex with F.IXa (F.Xase) and activates F.X.

#(b) A bispecific antibody binds to F.IXa and F.X and activates F.X.

#Multispecific antigen-binding molecules described herein comprise a first antigen-binding site and a second antigen-binding site that can specifically bind to at least two different types of antigens. While the first antigen-binding site and the second antigen-binding site are not particularly limited as long as they have an activity to bind to F.IX and/or F.IXa, and F.X, respectively, examples include sites necessary for binding with antigens, such as antibodies, scaffold molecules (antibody-like molecules) or peptides, or fragments containing such sites. Scaffold molecules are molecules that exhibit function by binding to target molecules, and any polypeptide may be used as long as they are conformationally stable polypeptides that can bind to at least one target antigen. Examples of such polypeptides include antibody variable regions, fibronectin (WO 2002/032925), protein A domain (WO 1995/001937), LDL receptor A domain (WO 2004/044011, WO 2005/040229), ankyrin (WO 2002/020565), and such, and also molecules described in documents by Nygren et al. (Current Opinion in Structural Biology, 7: 463-469 (1997); and Journal of Immunol Methods, 290: 3-28 (2004)), Binz et al. (Nature Biotech 23: 1257-1266 (2005)), and Hosse et al. (Protein Science 15: 14-27 (2006)). Furthermore, as mentioned in Curr Opin Mol Ther. 2010 August; 12(4): 487-95 and Drugs. 2008; 68(7): 901-12, peptide molecules that can bind to target antigens may be used.

#Herein, multispecific antigen-binding molecules are not particularly limited as long as they are molecules that can bind to at least two different types of antigens, but examples include polypeptides containing the above-mentioned antigen-binding sites, such as antibodies and scaffold molecules as well as their fragments, and aptamers comprising nucleic acid molecules and peptides, and they may be single molecules or multimers thereof. Preferred multispecific antigen-binding molecules include multispecific antibodies that can bind specifically to at least two different antigens. Particularly preferred examples of antibodies which have an activity of functionally substituting for F.VIII of the present invention include bispecific antibodies (BsAb) that can bind specifically to two different antigens (they may also be called dual specific antibodies).

#In the present invention, the term “commonly shared L chain” refers to an L chain that can link with two or more different H chains, and show binding ability to each antigen. Herein, the term “different H chain(s)” preferably refers to H chains of antibodies against different antigens, but is not limited thereto, and also refers to H chains whose amino acid sequences are different from each other. Commonly shared L chain can be obtained, for example, according to the method described in WO 2006/109592.