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Concomitant immunosuppressant use with pegloticase in patients with tophaceous gout - A case series

Michael Y. Bessen, Sarah Y. Bessen & Christianne M. Yung

Introduction: Treatment of tophaceous gout with pegloticase is often complicated by the production of anti-pegloticase antibodies. These antibodies result in increased risk of infusion reactions, loss of drug efficacy, and high discontinuation rate. Steroids are used in premedication to reduce potential infusion reactions; however prolonged usage of steroids is associated with significant adverse effects. Objective: To describe the use of immunosuppressants to reduce the incidence of infusion reactions with pegloticase treatment and the potential reduction of steroid use in premedication. Methods: We report seven cases of immunosuppressant use, initiated on the day of the first pegloticase infusion, as an adjunct to treatment with pegloticase for tophaceous gout. Results: Patient 1 was treated for tophaceous gout with oral methotrexate initiated at his first infusion. Low serum urate levels were achieved but urate increased on two occasions after two separate lapses in methotrexate compliance. In each instance, initiation of a higher dose of methotrexate restored pegloticase response. The patient tolerated all treatments without infusion reaction. Patients 2-6 were treated for tophaceous gout with oral methotrexate initiated at their first infusions. For Patient 2, methotrexate was switched to azathioprine at her fifth infusion due to fatigue. All five patients achieved low serum uric acid (sUA) levels, completed their treatments, and did not experience infusion reactions. Patient 7 was treated for tophaceous gout with oral cyclosporine initiated at his first infusion. Methotrexate was not used due to elevated liver function enzymes at baseline. He achieved a low sUA level and was able to complete his treatment without experiencing an infusion reaction. All of the patients were able to decrease their steroid use in pre-medication. Six of the seven were able to discontinue steroid use in pre-medication without developing infusion reactions. Conclusion: Concomitant use of immunosuppressive therapy with pegloticase may play a role in preventing infusion reactions, allow reduction of steroids in pre-medication, and result in improved outcomes. We have demonstrated that immunosuppressive therapy may be initiated on the day of the first infusion. Additionally, therapy does not seem to be confined to a single immunosuppressant; thus, immunosuppressive therapy may be tailored to a patient’s needs. The use of concomitant immunosuppressants with pegloticase treatment warrants further study.