Compstatin analogs with improved activity

Abstract

Compounds comprising peptides and peptidomimetics capable of binding the C3 protein and inhibiting complement activation are disclosed. These compounds display improved complement activation-inhibitory activity as compared with currently available compounds. Isolated nucleic acid molecules encoding the peptides are also disclosed.

What is claimed: 
     
         1 . A method of making compound that inhibits complement activation, wherein the compound comprises a peptide having a sequence: 
       
         
           
                 
               
                   (SEQ ID NO: 15) 
                 
                 
               
                   Xaa1-Cys-Val-Xaa2-Gln-Asp-Trp-Gly-Xaa3-His-Arg- 
                 
                     
                 
                   Cys-Xaa4; 
                 
             
                
               
            
             
                
                
                
               
            
           
         
         wherein: 
         Xaa1 is Ile, Val, Leu, Ac-Ile, Ac-Val, Ac-Leu or a dipeptide comprising Gly-Ile; 
         Xaa2 is Trp or a peptidic or non-peptidic analog of Trp; 
         Xaa3 is His, Ala, Phe or Trp; and 
         Xaa4 is L-Thr, D-Thr, Ile, Val, Gly, or a tripeptide comprising Thr-Ala-Asn, wherein a carboxy terminal —OH of any of the L-Thr, D-Thr, Ile, Val, Gly or Asn optionally is replaced by —NH 2 ; 
         the method comprising synthesizing the peptide by condensation of the amino acid residues or analogs thereof, or expressing a polynucleotide encoding the peptide. 
       
     
     
         2 . The method of  claim 1 , further comprising cyclizing the peptide through formation of a disulfide bond between the two Cys residues. 
     
     
         3 . The method of  claim 1 , further comprising actylation of Xaa1. 
     
     
         4 . The method of  claim 1 , further comprising replacement of the carboxy terminal —OH with —NH 2 . 
     
     
         5 . The method of  claim 1 , wherein Xaa1 is Ac-Ile. 
     
     
         6 . The method of  claim 1 , wherein Xaa3 is Ala. 
     
     
         7 . The method of  claim 1 , wherein Xaa2 is an analog of Trp comprising a substituted or unsubstituted bicyclic aromatic ring component or two or more substituted or unsubstituted monocyclic aromatic ring components. 
     
     
         8 . The method of  claim 7 , wherein the analog of Trp is selected from the group consisting of 2-naphthylalanine, 1-naphthylalanine, 2-indanylglycine carboxylic acid, dihydrotryptophan and benzoylphenylalanine. 
     
     
         9 . The method of  claim 1 , wherein Xaa1 is Ac-Ile, Xaa2 is Trp or an analog of Trp comprising a substituted or unsubstituted indole, naphthyl or dibenzoyl component, Xaa3 is Ala and Xaa4 is L-Thr or D-Thr; wherein a carboxy terminal —OH of either of the L-Thr or D-Thr optionally is replaced by —NH 2 ; and the two Cys residues are joined by a disulfide bond. 
     
     
         10 . The method of  claim 9 , wherein the peptide has a sequence selected from the group consisting of SEQ ID NO:4, SEQ ID NO:5, SEQ ID NO:6, SEQ ID NO:7, SEQ ID NO:8, SEQ ID NO:9, SEQ ID NO:10, SEQ ID NO:11, SEQ ID NO:12 and SEQ ID NO:13. 
     
     
         11 . The method of  claim 1 , wherein Xaa1 is a dipeptide Gly-Ile, and Xaa 4 is a tripeptide Thr-Ala-Asn; wherein wherein a carboxy terminal —OH of either of the L-Thr or D-Thr optionally is replaced by —NH 2 . 
     
     
         12 . The method of  claim 11 , wherein the peptide comprises SEQ ID NO:14. 
     
     
         13 . The method of  claim 12 , comprising providing a nucleic acid molecule that encodes a concatemer of two or more of a peptide comprising SEQ ID NO:14, wherein the encoded concatemer is cleavable by hydrazine to form a multiplicity of peptides comprising SEQ ID NO:14. 
     
     
         14 . A method of inhibiting complement activation on or in a medium in which complement activation is occurring, the method comprising contacting the medium with a compound comprising a peptide having a sequence: 
       
         
           
                 
               
                   (SEQ ID NO: 15) 
                 
                 
               
                   Xaa1-Cys-Val-Xaa2-Gln-Asp-Trp-Gly-Xaa3-His-Arg- 
                 
                     
                 
                   Cys-Xaa4; 
                 
             
                
               
            
             
                
                
                
               
            
           
         
         wherein: 
         Xaa1 is Ile, Val, Leu, Ac-Ile, Ac-Val, Ac-Leu or a dipeptide comprising Gly-Ile; 
         Xaa2 is Trp or a peptidic or non-peptidic analog of Trp; 
         Xaa3 is His, Ala, Phe or Trp; 
         Xaa4 is L-Thr, D-Thr, Ile, Val, Gly, or a tripeptide comprising Thr-Ala-Asn, wherein a carboxy terminal —OH of any of the L-Thr, D-Thr, Ile, Val, Gly or Asn optionally is replaced by —NH 2 ; and the two Cys residues are joined by a disulfide bond; 
         wherein the contacting results in the inhibition of complement activation on or in the medium. 
       
     
     
         15 . The method of  claim 14 , wherein the medium is one or more of (a) blood or serum; (b) tissues or organs; (c) artificial organs or implants; and (d) physiological fluids during extracorporeal shunting of the fluids. 
     
     
         16 . The method of  claim 15 , adapted for use in treatment of a disease or condition in which complement activation contributes to cell damage or injury. 
     
     
         17 . The method of  claim 14 , in which the medium is a testing medium and the method is adapted to screen test compounds for their ability to inhibit complement activation. 
     
     
         18 . The method of  claim 17 , wherein the test compound is screened for its ability to compete with the compound for binding to C3 or a C3 fragment. 
     
     
         19 . A medium comprising a compound that inhibits complement activation, wherein the compound comprises a peptide having a sequence: 
       
         
           
                 
               
                   (SEQ ID NO: 15) 
                 
                 
               
                   Xaa1-Cys-Val-Xaa2-Gln-Asp-Trp-Gly-Xaa3-His-Arg- 
                 
                     
                 
                   Cys-Xaa4; 
                 
             
                
               
            
             
                
                
                
               
            
           
         
         wherein: 
         Xaa1 is Ile, Val, Leu, Ac-Ile, Ac-Val, Ac-Leu or a dipeptide comprising Gly-Ile; 
         Xaa2 is Trp or a peptidic or non-peptidic analog of Trp; 
         Xaa3 is His, Ala, Phe or Trp; 
         Xaa4 is L-Thr, D-Thr, Ile, Val, Gly, or a tripeptide comprising Thr-Ala-Asn, wherein a carboxy terminal —OH of any of the L-Thr, D-Thr, Ile, Val, Gly or Asn optionally is replaced by —NH 2 ; and the two Cys residues are joined by a disulfide bond. 
       
     
     
         20 . The medium of  claim 19 , selected from an organ, a tissue, an artificial organ, an artificial implant, tubing, and any combination thereof.