Effectiveness and Safety of Sarilumab in Polymyalgia Rheumatica: a retrospective study of the FIRST Registry

To evaluate the effectiveness of sarilumab in patients with polymyalgia rheumatica (PMR) who were clinically assessed as having coexisting rheumatoid arthritis (RA).

Using data from the FIRST registry, a cohort of patients initiating molecular targeted therapy for RA, we identified cases from 2003 to April 2024 in which sarilumab was introduced as the first biologic agent and PMR was concurrently diagnosed. As a control group, we selected patients hospitalized for PMR flare during the same period who received standard of care (SoC) without biologic therapy. The primary outcome was the clinical Polymyalgia Rheumatica Activity Score (clin-PMR-AS) at 52 weeks post-treatment initiation.

Among 5,645 registered cases, 67 patients were identified as having PMR with coexisting RA and received sarilumab as their initial biologic therapy. The control group comprised 76 patients treated with conventional therapy alone. The 52-weeks continuation rate of sarilumab was 77.5%, indicating high treatment persistence. At 52 weeks, clin-PMR-AS scores decreased in both groups. Logistic regression analysis using low disease activity at 52 weeks as the outcome revealed sarilumab use as a significant predictor. After adjusting for baseline differences using inverse probability weighting based on propensity scores, the sarilumab group showed a significantly greater reduction in clin-PMR-AS compared to the SoC group.

These findings suggest that sarilumab may have the potential to improve disease activity in polymyalgia rheumatica compared to conventional therapy.