Pegylated L-Asparaginase

Abstract

Disclosed is a conjugate of a protein having substantial L-asparagine aminohydrolase activity and polyethylene glycol. In particular, the polyethylene glycol has a molecular weight less than or equal to about 5000 Da and the protein is an L-asparaginase from Erwinia . The conjugate of the invention has shown superior properties such as maintenance of a high level of in vitro activity and an unexpected increase in half-life in vivo. Also disclosed are methods of producing the conjugate and use of the conjugate in therapy. In particular, a method is disclosed for use of the conjugate in the treatment of cancer, particularly Acute Lymphoblastic Leukemia (ALL). More specifically, a method is disclosed for use of the conjugate as a second line therapy for patients who have developed hypersensitivity or have had a disease relapse after treatment with other L-asparaginase preparations.

1 . A conjugate comprising an L-asparaginase from  Erwinia chrysanthemi  having the amino acid of SEQ ID NO: 1 and polyethylene glycol (PEG), wherein the PEG has a molecular weight less than or equal to about 5000 Da. 
     
     
         2 - 30 . (canceled) 
     
     
         31 . The conjugate of  claim 1 , wherein the PEG is covalently linked to one or more amino groups of said L-asparaginase. 
     
     
         32 . The conjugate of  claim 31 , wherein the PEG is covalently linked to said one or more amino groups by an amide bond. 
     
     
         33 . (canceled) 
     
     
         34 . The conjugate of  claim 31 , wherein the PEG is covalently linked to at least from about 40% to about 90% of total amino groups. 
     
     
         35 - 38 . (canceled) 
     
     
         39 . The conjugate of  claim 1 , wherein said PEG is monomethoxy-polyethylene glycol. 
     
     
         40 - 49 . (canceled) 
     
     
         50 . A method of treating a disease treatable by L-asparagine depletion in a human patient, said method comprising administering to said patient an effective amount of the conjugate  claim 1 . 
     
     
         51 . The method of  claim 50 , wherein said disease treatable by L-asparagine depletion is a cancer. 
     
     
         52 . The method of  claim 51 , wherein said cancer is selected from the group consisting of Acute Lymphoblastic Leukemia (ALL), acute myeloid leukemia (AML), non-Hodgkin's lymphoma, NK lymphoma, and pancreatic cancer. 
     
     
         53 . The method of  claim 52 , wherein said cancer is ALL. 
     
     
         54 . The method of  claim 53 , wherein said conjugate is administered at an amount of about 5 U/kg to about 25 U/kg. 
     
     
         55 . The method of  claim 54 , wherein said conjugate is administered at an amount of about 25 U/kg. 
     
     
         56 - 59 . (canceled) 
     
     
         60 . The method of  claim 50 , wherein said conjugate is administered intravenously. 
     
     
         61 . The method of  claim 50 , wherein said conjugate is administered intramuscularly. 
     
     
         62 . The method of  claim 50 , wherein said conjugate is administered once per week. 
     
     
         63 . The method of  claim 50 , wherein. said conjugate is administered twice per week. 
     
     
         64 . The method of  claim 50 , wherein said conjugate is administered less than once per week. 
     
     
         65 . The method of  claim 50 , wherein said conjugate is administered as monotherapy. 
     
     
         66 . The method of  claim 65 , wherein said conjugate is not administered with an asparagine synthetase inhibitor. 
     
     
         67 . The method of  claim 50 , wherein said human patient has had a previous hypersensitivity to an  E. coli  L-asparaginase or PEGylated form thereof. 
     
     
         68 . (canceled) 
     
     
         69 . The method of  claim 67 , wherein said hypersensitivity is selected from the group consisting of allergic reaction, anaphylactic shock, and silent hypersensitivity. 
     
     
         70 . The method of  claim 50 , wherein said human patient has had a disease relapse. 
     
     
         71 . The method of  claim 70 , wherein said disease relapse occurs after treatment with an  E. coli  L-asparaginase or PEGylated form thereof. 
     
     
         72 - 94 . (canceled)