Methods and kits for predicting infusion reaction risk and antibody-mediated loss of response by monitoring serum uric acid during pegylated uricase therapy

A method of lowering the risk of an infusion reaction while treating chronic gout refractory to conventional therapy in a patient, the method comprising:

• a. intravenously administering to the patient a PEGylated uricase protein every 2 or every 4 weeks;
• b. measuring the serum uric acid level of the patient after each said administration;
• and
• c. either continuing to administer the PEGylated uricase protein if the patient's serum uric acid is measured to be less than 6 mg/dl, or discontinuing administration of the PEGylated uricase protein if the patient's serum uric acid level is measured to be at least 6 mg/dl, thereby lowering the risk of an infusion reaction;
• wherein the PEGylated uricase protein is selected from the group consisting of an Aspergillus flavus uricase that has been PEGylated, an Arthrobacter globiformis uricase that has been PEGylated, a Candida utilis uricase that has been PEGylated, and pegloticase;
• and
• wherein each polyethylene glycol (PEG) molecule of the PEGylated uricase has a molecular weight between 1 kDa and 50 kDa.