Real-World Effectiveness of Pegloticase Associated with Use of Concomitant Immunomodulatory Therapy.

Abstract

The objective was to ascertain pegloticase persistence and adverse events associated with concomitant immunomodulatory drug use in patients with gout. We conducted a retrospective analysis of gout patients using the ACR's Rheumatology Informatics System for Effectiveness (RISE) registry from 1/2016 through 6/2020. The first pegloticase infusion defined the index date. Based on concomitant immunomodulatory drug use, we identified 3 exposure groups: 1) Immunomodulatory drug initiators - patients initiating an immunomodulatory prescription ±60 days from index date; 2) Immunomodulatory drug prevalent users - patients receiving their first immunomodulatory drug prescription >60 days before the index date with at least one prescription within ±60 days of index date; and 3) Immunomodulatory non-users - patients receiving pegloticase without concomitant IMM drugs. We calculated the proportion of patients achieving a serum urate (SU) ≤6mg/dL and with lab abnormalities (WBC <3.4; platelets <135,000; HCT <30; ALT or AST ≥1.5X ULN) within 180 days after the index date. Cox regression analyzed time to pegloticase discontinuation controlling for potential confounders. We identified 700 pegloticase users (91 immunomodulatory drug initiators, 33 immunomodulatory drug prevalent users, and 576 non-users) with median follow-up of 14 months. Immunomodulatory drug users were less likely to discontinue pegloticase. The adjusted hazard ratio of pegloticase discontinuation associated with concomitant immunomodulatory drug initiation was 0.52 (95% CI: 0.37,0.75) and 0.69 (95% CI: 0.42,1.16) for prevalent users. Lab abnormalities were uncommon (<5%) and were not higher with concomitant immunomodulatory use. Consistent with clinical trials, results from this large observational registry suggest that concomitant immunomodulatory drug use improves pegloticase persistence.