Use of VEGF inhibitors for treatment of eye disorders

#Statement Regarding Related Art

#A class of cell-derived dimeric mitogens with selectivity for vascular endothelial cells has been identified and designated vascular endothelial cell growth factor (VEGF). VEGF is a dimer with an apparent molecular mass of about 46 kDa with each subunit having an apparent molecular mass of about 23 kDa. The membrane-bound tyrosine kinase receptor, known as Flt (also known as VEGFR2), was shown to be a VEGF receptor (DeVries et al. (1992) Science 255:989-991). Another form of the VEGF receptor, designated KDR or Flk-1 (also known as VEGFR3), is also known to bind VEGF and induce mitogenesis (Terman et al. (1991) Oncogene 6:1677-1683; Terman et al. (1992) Biochem. Biophys. Res. Comm. 187:1579-1586).

#U.S. Pat. No. 6,011,003 describes an altered, soluble form of Fit polypeptide capable of binding to VEGF comprising five or fewer complete immunoglobulin domains. WO 97/44453 describes chimeric VEGF receptor proteins comprising amino acid sequences derived from VEGF receptors Flt1 and KDR.

#FIG. 1. Biacore analysis of binding stoichiometry. Binding stoichiometry was calculated as a molar ratio of bound VEGF165 to the immobilized Flt1D2Flk1D3.FcΔC1(a) or VEGFR1R2-FcΔC1(a), using the conversion factor of 1000 RU equivalent to 1 ng/ml.

#FIG. 2. Pharmacokinetics of Flt1 (1-3)-Fc (A40), Flt1D2.Flk1D3.FcΔC1(a) and VEGFR1R2-FcΔC1(a).

#FIG. 3. Pharmacokinetics of Flt1 (1-3)-Fc (A40), Flt1D2.Flk1D3.FcΔC1(a) and Flt1D2.VEGFR3D3.FcΔC1(a).

#It has been a longstanding problem in the art to produce a receptor-based VEGF antagonist that has a pharmacokinetic profile that is appropriate for consideration of the antagonist as a therapeutic candidate. Applicants describe herein, for the first time, a chimeric polypeptide molecule, capable of antagonizing VEGF activity, that exhibits improved pharmacokinetic properties as compared to other known receptor-based VEGF antagonists. The chimeric polypeptide molecules described herein thus provide appropriate molecules for use in therapies in which antagonism of VEGF is a desired result.

#The extracellular ligand binding domain is defined as the portion of a receptor that, in its native conformation in the cell membrane, is oriented extracellularly where it can contact with its cognate ligand. The extracellular ligand binding domain does not include the hydrophobic amino acids associated with the receptor's transmembrane domain or any amino acids associated with the receptor's intracellular domain. Generally, the intracellular or cytoplasmic domain of a receptor is usually composed of positively charged or polar amino acids (i.e., lysine, arginine, histidine, glutamic acid, aspartic acid). The preceding 15-30, predominantly hydrophobic or apolar amino acids (i.e., leucine, valine, isoleucine, and phenylalanine) comprise the transmembrane domain. The extracellular domain comprises the amino acids that precede the hydrophobic transmembrane stretch of amino acids. Usually the transmembrane domain is flanked by positively charged or polar amino acids such as lysine or arginine. von Heijne has published detailed rules that are commonly referred to by skilled artisans when determining which amino acids of a given receptor belong to the extracellular, transmembrane, or intracellular domains (See, von Heijne (1995) BioEssays 17:25).

#Nucleic Acid Constructs and Encoded Fusion Polypeptides