What precautions need to be taken when prescribing and administering pegloticase?
• Low G6PD enzyme activity (deficiency) is a contraindication due to risk of hemolytic anemia and methemoglobinemia. All patients must be screened for G6PD deficiency.
• Pegloticase profoundly lowers the uric acid level in 24 hours; without prophylaxis, 80% of patients will suffer an acute gout flare. Start prophylaxis (NSAIDs, colchicine, or prednisone) 1 week prior to initial infusion of pegloticase.
• Infusion reactions occur in 25% of patients even if uric acid is <6 mg/dL. Incidence increases with longer gaps between infusions. Pretreatment is critical to lowering this risk (antihistamines, acetaminophen, and corticosteroids; see Question 14 for a typical pretreatment regimen).
• Pegloticase is associated with a high rate of development of antipegloticase antibodies. These antibodies are associated with infusion reactions including anaphylaxis (7%).
• Check serum uric acid prior to each infusion after the initial dose. A serum uric acid level >6 mg/dL reflects loss of efficacy due to antibody development—discontinue pegloticase.
• Pegloticase should not be used in conjunction with other ULT; it can confound interpretation of uric acid levels.