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

OBJECTIVE:The objective was to ascertain pegloticase persistence and adverse events associated with concomitant immunomodulatory drug use in patients with gout. METHODS: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. RESULTS: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. CONCLUSION:Consistent with clinical trials, results from this large observational registry suggest that concomitant immunomodulatory drug use improves pegloticase persistence.