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 treating a patient suffering from gout having a serum uric acid (SUA) level of 6 mg/dl or less and reducing the incidence of infusion reaction in the patient during PEGylated uricase therapy without measuring anti-PEGylated uricase and anti-PEG antibody titers, comprising the steps of:

• intravenously administering to said patient a therapeutically effective amount of PEGylated uricase every two weeks;
• obtaining a biological sample from said patient after a period of at least 2 weeks, wherein said biological sample is selected from the group consisting of blood, serum, and plasma;
• measuring a uric acid level in said biological sample;
• and
• indicating that the uric acid level is associated with a lower likelihood of antibody-mediated PEGylated uricase clearance when said uric acid level is maintained at less than 6 mg/dl or indicating that said uric acid level is associated with a higher likelihood of antibody-mediated PEGylated uricase clearance at a time point when said uric acid level is measured at least 6 mg/dl;
• if said uric acid level is less than 6 mg/dl then continuing said administration of PEGylated uricase every two weeks;
• or
• if said uric acid level is above 6 mg/dl then discontinuing said administration of PEGylated uricase every two weeks, thereby reducing the incidence of infusion reaction in said patient;
• wherein said patient previously received ineffective allopurinol therapy or has a medical history in which allopurinol therapy is contraindicated.