Methods and compositions for increasing alpha-l-iduronidase activity in the cns

Abstract

Provided herein are methods and compositions for treating a subject suffering from a deficiency in α-L-Iduronidase in the CNS. The methods include systemic administration of a bifunctional fusion antibody comprising an antibody to a human insulin receptor and an α-L-Iduronidase. A therapeutically effective systemic dose is based on the specific CNS uptake characteristics of human insulin receptor antibody-α-L-Iduronidase fusion antibodies as described herein.

1 .- 23 . (canceled) 
     
     
         24 . A pharmaceutical composition comprising an alpha-L-iduronidase (IDUA) covalently linked to an antibody fragment capable of binding to an endogenous receptor of a blood brain barrier (BBB) transport system,
 wherein the IDUA retains at least 30% of its enzymatic activity compared to an unfused IDUA, and wherein the enzymatic activity is determined with a fluorometric assay using 4-methylumbelliferyl α-L-iduronide.   
     
     
         25 . The pharmaceutical composition of  claim 24 , wherein the endogenous receptor of the BBB is an insulin receptor. 
     
     
         26 . The pharmaceutical composition of  claim 24 , wherein the endogenous receptor of the BBB is a transferrin receptor. 
     
     
         27 . The pharmaceutical composition of  claim 24 , wherein the antibody fragment is a Fab fragment. 
     
     
         28 . The pharmaceutical composition of  claim 27 , wherein the Fab fragment heavy chain comprises a CDR1 corresponding to the amino acid sequence of SEQ ID NO:1, a CDR2 corresponding to the amino acid sequence of SEQ ID NO:2, and a CDR3 corresponding to the amino acid sequence of SEQ ID NO:3. 
     
     
         29 . The pharmaceutical composition of  claim 27 , wherein the Fab fragment light chain comprises a CDR1 corresponding to the amino acid sequence of SEQ ID NO:4, a CDR2 corresponding to the amino acid sequence of SEQ ID NO:5, and a CDR3 corresponding to the amino acid sequence of SEQ ID NO:6. 
     
     
         30 . The pharmaceutical composition of  claim 27 , wherein the amino acid sequence of the IDUA is covalently linked to the carboxy terminus of the amino acid sequence of the Fab fragment heavy chain. 
     
     
         31 . The pharmaceutical composition of  claim 30 , wherein the fusion protein further comprises a linker between the amino acid sequence of the IDUA and the carboxy terminus of the amino acid sequence of the Fab fragment heavy chain. 
     
     
         32 . The pharmaceutical composition of  claim 24 , wherein an IDUA specific activity of the fusion antibody is at least about 200,000 units/mg. 
     
     
         33 . The pharmaceutical composition of  claim 24 , wherein the pharmaceutical composition is sterile filtered. 
     
     
         34 . The pharmaceutical composition of  claim 24 , wherein the pharmaceutical composition further comprises a salt selected from the group consisting of mineral acid salts and organic acid salts. 
     
     
         35 . The pharmaceutical composition of  claim 34 , wherein the mineral acid salt is selected from the group consisting of hydrochlorides, hydrobromides, phosphates, and sulfates. 
     
     
         36 . The pharmaceutical composition of  claim 34 , wherein the organic acid salt is selected from the group consisting of acetates, propionates, malonates, and benzoates. 
     
     
         37 . The pharmaceutical composition of  claim 24 , wherein the pharmaceutical composition further comprises polysorbate-80 present in an amount between about 0.01% to about 1%. 
     
     
         38 . The pharmaceutical composition of  claim 24 , wherein the pharmaceutical composition further comprises a carbohydrate additive. 
     
     
         39 . The pharmaceutical composition of  claim 38 , wherein the carbohydrate additive is selected from the group consisting of mannitol, sorbitol, and trehalose.