Novel inhibitors of vascular endothelial growth factor activity, their uses and processes for their production

Abstract

The present invention is directed to novel chimeric VEGF receptor proteins comprising amino acid sequences derived from the vascular endothelial growth factor (VEGF) receptors flt-1 and KDR, including the murine homologue to the human KDR receptor FLK-1, wherein said chimeric VEGF receptor proteins bind to VEGF and antagonize the endothelial cell proliferative and angiogenic activity thereof. The present invention is also directed to nucleic acids and expression vectors encoding these chimeric VEGF receptor proteins, host cells harboring such expression vectors, pharmaceutically acceptable compositions comprising such proteins, methods of preparing such proteins and to methods utilizing such proteins for the treatment of conditions associated with undesired vascularization.

1 . A chimeric VEGF receptor protein being capable of binding to VEGF and thereby exerting an inhibitory effect thereon, wherein said chimeric VEGF receptor protein comprises immunoglobulin-like domains 1, 2 and 3 of the flt-1 and/or the KDR receptor or functional equivalents thereof.  
     
     
         2 . The chimeric VEGF receptor protein according to  claim 1  wherein immunoglobulin-like domains 1, 2 and 3 are all derived from the flt-1 receptor.  
     
     
         3 . The chimeric VEGF receptor protein according to  claim 1  wherein immunoglobulin-like domains 1, 2 and 3 are all derived from the KDR receptor.  
     
     
         4 . The chimeric VEGF receptor protein according to  claim 1  wherein immunoglobulin-like domains 1 and 3 are derived from the flt-1 receptor and immunoglobulin-like domain 2 is derived from the KDR receptor.  
     
     
         5 . The chimeric VEGF receptor protein according to  claim 1  wherein immunoglobulin-like domains 1 and 3 are derived from the KDR receptor and immunoglobulin-like domain 2 is derived from the flt-1 receptor.  
     
     
         6 . The chimeric VEGF receptor protein according to  claim 1  wherein immunoglobulin-like domains 1 and 2 are derived from the flt-1 receptor and immunoglobulin-like domain 3 is derived from the KDR receptor.  
     
     
         7 . The chimeric VEGF receptor protein according to  claim 1  wherein immunoglobulin-like domains 1 and 2 are derived from the KDR receptor and immunoglobulin-like domain 3 is derived from the flt-1 receptor.  
     
     
         8 . The chimeric VEGF receptor protein according to  claim 1  wherein immunoglobulin-like domain 1 is derived from the flt-1 receptor and immunoglobulin-like domains 2 and 3 are derived from the I<DR receptor.  
     
     
         9 . The chimeric VEGF receptor protein according to  claim 1  wherein immunoglobulin-like domain 1 is derived from the KDR receptor and immunoglobulin-like domains 2 and 3 are derived from the flt-1 receptor.  
     
     
         10 . The chimeric VEGF receptor protein according to  claim 1  wherein said immunoglobulin-like domains 1, 2 and 3 are fused to the Fc portion of a human IgG immunoglobulin.  
     
     
         11 . The chimeric VEGF receptor protein according to  claim 1  which is soluble.  
     
     
         12 . A chimeric VEGF receptor protein being capable of binding to VEGF and thereby exerting an inhibitory effect thereon, said chimeric VEGF receptor protein comprising the extracellular domain of the FLT4 receptor wherein immunoglobulin-like domain 2 of said FLT4 receptor is replaced by immunoglobulin-like domain 2 of the flt-1 or KDR receptor or a functional equivalent thereof and wherein one or more other immunoglobulin-like domains of said FLT4 receptor are or are not replaced by the corresponding immunoglobulin-like domain of the flt-1 or KDR receptor.  
     
     
         13 . The chimeric VEGF receptor protein according to  claim 12  having immunoglobulin-like domain 2 of the flt-1 receptor and immunoglobulin-like domains 1 and 3 to 7 of the FLT4 receptor.  
     
     
         14 . The chimeric VEGF receptor protein according to  claim 12  having immunoglobulin-like domains 1 to 3 of the flt-1 receptor and immunoglobulin-like domains 4 to 7 of the FLT4 receptor.  
     
     
         15 . The chimeric VEGF receptor protein according to  claim 12  whose amino acid sequence is shown in  FIG. 9 .  
     
     
         16 . The chimeric VEGF receptor protein according to  claim 12  whose amino acid sequence is shown in  FIG. 10 .  
     
     
         17 . The chimeric VEGF receptor protein according to  claim 12  which is soluble.  
     
     
         18 . The chimeric VEGF receptor protein according to  claim 12  which is membrane-bound.  
     
     
         19 . A nucleic acid encoding the chimeric VEGF receptor protein of  claim 1 .  
     
     
         20 . A replicable expression vector capable in a transformant host cell of expressing the chimeric VEGF receptor protein of  claim 1 .  
     
     
         21 . Host cells transformed with the replicable expression vector according to  claim 20 .  
     
     
         22 . Host cells according to  claim 21  which are CEN4 cells.  
     
     
         23 . A composition of matter comprising a chimeric VEGF receptor protein according to  claim 1  compounded with a pharmaceutically acceptable carrier.  
     
     
         24 . A method of producing a chimeric VEGF receptor protein comprising the steps of introducing into a suitable expression system the expression vector of  claim 20  and effecting the expression of said chimeric VEGF receptor protein.  
     
     
         25 . A method of therapeutically treating a mammal for a condition associated with undesired vascularization, said method comprising administering to said mammal a therapeutically effective amount of a composition according to  claim 23 .  
     
     
         26 . The method according to  claim 25  wherein said condition associated with undesired vascularization includes the formation of a tumor.  
     
     
         27 . The method according to  claim 26  wherein said tumor is malignant.  
     
     
         28 . A method of substantially inhibiting VEGF activity in a mammal comprising administering to said mammal a VEGF inhibiting amount of a chimeric VEGF receptor protein according to  claim 1.