Observational Study of the Use of Pegloticase (KRYSTEXXA®) in Refractory Chronic Gout

Number of Participants With Infusion Reactions

Infusion reactions were defined as adverse events (AEs) or clusters of events, not attributable to another cause that occurred during or within 2 hours after the infusion of pegloticase. Any other case that occurred outside of the 2-hour window was categorized per Investigator discretion.

Time frame: 52 weeks

Number of Participants With Anaphylaxis

Anaphylaxis was defined using the National Institute of Allergy and Infectious Disease/Food Allergy and Anaphylaxis Network (NIAID/FAAN) criteria: Acute onset of an illness (minutes to several hours) with involvement of the skin, mucosal tissue, or both (e.g., generalized hives; pruritus or flushing; swollen lips, tongue, or uvula), and at least 1 of the following: 1. Respiratory compromise (e.g., dyspnea, wheeze-bronchospasm, stridor, reduced peak expiratory flow, hypoxemia). 2. Reduced blood pressure (i.e., systolic blood pressure \< 90 mm Hg or greater than 30% decrease from that patient's baseline) or associated symptoms of end-organ failure (e.g., hypotonia \[collapse\], syncope, incontinence).

Time frame: 52 weeks

Number of Participants With Immune Complex-related Events

Immune complex-related events were defined as any presumptive immune complex-related disorders that were confirmed by an appropriate investigation of the event and of complement markers (C3 and C4 levels). Clinical manifestations could have included skin rash, arthralgia, arthritis, proteinuria, serum sickness, and cryoglobulinemia.

Time frame: From first dose of study drug to the end of the 12-week follow-up period (63 weeks).