Conjugates of insulin-like growth factor-1 and poly(ethylene glycol)

Abstract

A conjugate consisting of an insulin-like growth factor- 1 (IGF-I) variant and one or two poly(ethylene glycol) group(s), characterized in that said IGF-I variant has an amino acid alteration at up to three amino acid positions 27, 37, 65, 68 of the wild-type IGF-I amino acid sequence so that one or two of said amino acids is/are lysine and amino acid 27 is a polar amino acid but not lysine, is conjugated via the primary amino group(s) of said lysine(s) and said poly(ethylene glycol) group(s) have an overall molecular weight of from 20 to 100 kDa is disclosed. This conjugate is useful for the treatment of neurodegenerative disorders like Alzheimer's Disease.

1 . A conjugate comprising an IGF-I variant and poly(ethylene glycol), wherein the IGF-I variant has at least one amino acid alteration selected from the group consisting of alterations at amino acid positions 27, 37, 65, and 68 of the wild-type IGF-I amino acid sequence wherein one or more of amino acids selected from the group consisting of 37, 65, and 68 is lysine, wherein amino acid 27 is a polar amino acid but is not lysine, and wherein said poly(ethylene glycol) is conjugated to said IGF-I variant via one or more primary amino groups.  
     
     
         2 . A conjugate according to  claim 1  wherein said poly(ethylene glycol) has an overall molecular weight of from 20 to 100 kDa.  
     
     
         3 . A conjugate according to  claim 1  wherein said IGF-I variant is additionally conjugated to poly(ethylene glycol) at the N-terminal amino acid.  
     
     
         4 . A conjugate according to  claim 1  wherein said IGF-I variant is conjugated to poly(ethylene glycol) at a member selected from the group consisting of lysine 65, lysine 68, and lysine 37 or is conjugated to poly(ethylene glycol) at both K65 and K68.  
     
     
         5 . A conjugate according to  claim 1  wherein said IGF-I variant is selected from the group consisting of RRKK, RRRK, RRKR, and RKRR.  
     
     
         6 . A conjugate according to  claim 1  wherein up to three amino acids at the N-terminus are truncated.  
     
     
         7 . An IGF-I variant selected from the group consisting of RRKK, RRRK, RRKR, and RKRR wherein up to three amino acids at the N-terminus are truncated.  
     
     
         8 . A conjugate according to  claim 1  wherein the poly(ethylene glycol) group(s) is/are branched poly(ethylene glycol) group(s).  
     
     
         9 . A conjugate according to  claim 1  wherein the poly(ethylene glycol) group(s) have an overall molecular weight of 20 kDa to 100 kDa.  
     
     
         10 . An IGF-I variant having at least one amino acid alteration selected from the group consisting of alterations at amino acid positions 27, 37, 65, and 68 of the wild-type IGF-I amino acid sequence wherein one or more of amino acids selected from the group consisting of 37, 65, and 68 is lysine, wherein amino acid 27 is a polar amino acid but is not lysine.  
     
     
         11 . A method for the preparation of a conjugate comprising an IGF-I variant and one or two poly(ethylene glycol) group(s), said poly(ethylene glycol) group(s) having an overall molecular weight of from about 20 to about 100 kDa, said method comprising reacting the IGF-intermediate of  claim 9  with activated (polyethylene) glycol under conditions such that said (polyethylene) glycol will react with one or two primary lysine amino groups of said IGF-I variant.  
     
     
         12 . The method according to  claim 11  further comprising reacting (polyethylene) glycol with said IGF-I intermediate via N-terminal amino group of said IGF-I intermediate to yield an IGF-I variant with poly(ethylene glycol) bound to both the N-terminal amino group and to one or two primary lysine, amino groups..  
     
     
         13 . A pharmaceutical composition comprising a conjugate of  claim 1  and a pharmaceutically acceptable carrier.  
     
     
         14 . A method for the treatment of Alzheimer's Disease comprising administering to a patient in need thereof a therapeutically effective amount of a conjugate of  claim 1 .  
     
     
         15 . A composition comprising a conjugate comprising an IGF-I variant and poly(ethylene glycol), wherein the IGF-I variant has at least one amino acid alteration selected from the group consisting of alterations at amino acid positions 27, 37, 65, and 68 of the wild-type IGF-I amino acid sequence wherein one or more of amino acids selected from the group consisting of 37, 65, and 68 is lysine, wherein amino acid 27 is a polar amino acid but is not lysine, and wherein said poly(ethylene glycol) is conjugated to said IGF-I variant via one or more primary amino groups) and an IGF-I variant which is conjugated to poly(ethylene glycol) at its N-terminus.  
     
     
         16 . A pharmaceutical composition comprising a conjugate comprising an IGF-I variant and poly(ethylene glycol), wherein the IGF-I variant has at least one amino acid alteration selected from the group consisting of alterations at amino acid positions 27, 37, 65, and 68 of the wild-type IGF-I amino acid sequence wherein one or more of amino acids selected from the group consisting of 37, 65, and 68 is lysine, wherein amino acid 27 is a polar amino acid but is not lysine, and wherein said poly(ethylene glycol) is conjugated to said IGF-I variant via one or more primary amino groups, an IGF-I variant which is conjugated to poly(ethylene glycol) at its N-terminus, and a pharmaceutically acceptable carrier.  
     
     
         17 . A method for the treatment of Alzheimer's Disease comprising administering to a patient in need thereof a therapeutically effective amount of a composition of claims  15 .  
     
     
         18 . A method for the treatment of Alzheimer's Disease comprising administering to a patient in need thereof a therapeutically effective amount of a composition of claims  16 .