Pegylated interleukin-10

Abstract

Interleukin-10 (IL-10) conjugated via a linker to one or more polyethylene glycol (PEG) molecules at a single amino acid residue of the IL-10, and a method for preparing the same, are provided. The method produces a stable mono-pegylated IL-10, which retains IL-10 activity, where pegylation is selective for the N-terminus on one subunit of IL-10 with little or no formation of monomeric IL-10. The method also provides a substantially homogenous population of mono-PEG-IL-10.

1 . A mono-PEG-IL-10. 
   
   
       2 . The mono-PEG-IL-10 of  claim 1 , comprising one or two PEG molecules covalently attached via a linker to one amino acid residue on IL-10, wherein the attachment is at an N-terminal amino acid residue or on a lysine residue. 
   
   
       3 . The mono-PEG-IL-10 of  claim 2 :
 (a) which comprises a methoxy PEG;   (b) wherein the IL-10 is human IL-10;   (c) wherein the total molecular mass of all PEG covalently attached to the linker is from 3,000 daltons to 60,000 daltons; or   (d) wherein the linker is a linear or branched C 1-11  alkyl.   
   
   
       4  . The mono-PEG-IL-10 of  claim 2 , wherein the total molecular mass of all PEG covalently attached to the linker is from 10,000 daltons to 36,000 daltons. 
   
   
       5 . The mono-PEG-IL-10 of  claim 2 , wherein the linker is a linear C 3  alkyl. 
   
   
       6  . The mono-PEG-IL-10 of  claim 1 , wherein a PEG molecule is covalently attached to the alpha amino group of one N-terminus of IL-10 via a linear C 3  alkyl linker. 
   
   
       7  . A PEG-IL-10 comprising the formula:
   [X-O(CH 2 CH 2 O) n ] b -L-NH-IL-10,   
     where X is H or C 14  alkyl, n is 20 to 2300, b is 1 to 9 and L is a C 1-11  alkyl linker moiety which is covalently attached to nitrogen (N) of the alpha amino group at the amino terminus of one IL-10 subunit, provided that when b is greater than 1 the total of n does not exceed 2300. 
   
   
       8 . A PEG-IL-10 of  claim 7 , wherein L is —CH 2 CH 2 CH 2 —. 
   
   
       9 . A pharmaceutical composition, comprising a mono-PEG-IL-10 of  claim 1  in combination with a pharmaceutically acceptable carrier. 
   
   
       10 . A method of treating inflammation in an individual in need of such treatment, comprising administering to the individual a therapeutically effective amount of a pharmaceutical composition of  claim 9 . 
   
   
       11 . A process for preparing a mono-PEG-IL-10, comprising the step of:
 reacting IL-10 with an activated PEG-aldehyde linker in the presence of a reducing agent to form the mono-PEG-IL-10,   wherein the linker is covalently attached to one amino acid residue of the IL-10.   
   
   
       12 . The process of  claim 11  wherein:
 (a) the reducing agent is sodium cyanoborohydride;   (b) the activated PEG-aldehyde linker is PEG-propionaldehyde;   (c) the PEG is a methoxy-PEG;   (d) the linker is multi-armed;   (e) the ratio of IL-10 to the sodium cyanoborohydride is from about 1:0.5 to 1:50;   (f) the total molecular mass of all PEG comprising the PEG-aldehyde linker is from 3,000 daltons to 60,000 daltons; or   (g) the reacting step is performed at a pH of 5.5 to 7.8.   
   
   
       13 . The process of  claim 11 , wherein the ratio of IL-10 to the sodium cyanoborohydride is 1:5 to 1:15. 
   
   
       14 . The process of  claim 11 , wherein the total molecular mass of all PEG comprising the PEG-aldehyde linker is from 10,000 daltons to 36,000 daltons. 
   
   
       15 . The process of  claim 11 , wherein the reacting step is performed at a pH of 6.3 to 7.5. 
   
   
       16 . The process of  claim 11 , further comprising a step selected from:
 incubating the mono-PEG-IL-10 product in a buffer at pH 5.0 to 9.0; and   treating the mono-PEG-IL-10 product with 0.05 to 0.4 M hydroxylamine HCl salt.   
   
   
       17 . A process for preparing a mono-PEG-IL-10, comprising the step of:
 reacting IL-10 with an activated PEG-propionaldehyde linker in the presence of sodium cyanoborohydride, wherein the molar ratio of IL-10 to sodium cyanoborohydride is from about 1:5 to about 1:15, at a pH of about 6.3 to about 7.5 and a temperature of from 18° C. to 25° C. to form the mono-PEG-IL-10,   wherein the linker is covalently attached to one amino acid residue of the IL-10.   
   
   
       18 . The process of  claim 17 , wherein the total molecular mass of all PEG comprising the PEG-aldehyde linker is from 10,000 daltons to 36,000 daltons. 
   
   
       19 . The process of  claim 17 , further comprising a step selected from:
 incubating the mono-PEG-IL-10 product in a TRIS buffer at pH 7.0 to 8.0; and   treating the mono-PEG-IL-10 product with 0.05 to 0.4 M hydroxylamine HCl salt.   
   
   
       20 . A PEG-IL-10 prepared according to a process of  claim 11 .