Background/Purpose: Sarilumab is a human monoclonal antibody that binds to membrane and soluble IL-6R, which is approved for the treatment of moderate to severe rheumatoid arthritis (RA) in adult patients. In MONARCH (NCT02332590), sarilumab 200 mg monotherapy administered every 2 weeks (q2w) was superior to adalimumab monotherapy 40 mg q2w, among patients with RA intolerant of, inappropriate candidates for, or inadequate responders to methotrexate (MTX-IR).¹ Safety profiles of both therapies were consistent with previously reported data with this class.¹ Patients completing MONARCH could enter the open-label extension (OLE [maximum duration 276 weeks]), where all patients received sarilumab 200 mg q2w. The objective of the study was to compare patient-reported outcomes (PROs) among patients remaining on sarilumab (continuation group) vs patients switching from adalimumab to sarilumab (switch group) in the OLE.

Methods: PROs assessed at entry into the OLE and at week 24 of the OLE are shown in the Table. Patient global assessment of disease activity (PtGA) by visual analog scale (VAS), pain VAS and Health Assessment Questionnaire Disability Index (HAQ-DI) were also assessed at week 48 of the OLE. P-values for all PROs in the OLE were considered nominal. Available safety data were reported for all patients who reached week 52 of the OLE as of March 2017.

Results: Of 321 patients who completed MONARCH, 320 entered the OLE; 155 in the switch and 165 in the continuation groups. From entry to the OLE through week 24 of the OLE, when all patients received sarilumab, the switch and continuation groups reported further improvements in PROs, including FACIT-F and RAID. Patients in the continuation group reported better SF-36 physical component summary (PCS), physical and social functioning domain scores, and less work days missed due to RA (P≤0.05) (Table). PtGA VAS, pain VAS, and HAQ-DI were stable in both groups from week 24 of the OLE through week 48 of the OLE (data not shown). Available safety data showed 76.1% vs 70.9% treatment-emergent adverse events (TEAEs), 11.0% vs 3.6% serious adverse events, and 6.5% vs 7.3% TEAEs leading to treatment discontinuation in the switch and continuation groups, respectively. Two deaths occurred in the switch and one in the continuation groups.

Conclusion: Sarilumab was superior to adalimumab in many PROs at the end of MONARCH. In the OLE, where all patients received sarilumab, patients in the switch group reported similar improvements in PROs as the continuation group, with the two groups reporting similar outcomes by weeks 24 and 48 of the OLE, except in SF-36 PCS, physical function and social function domains, and work days missed due to RA, where patients in the switch group reported better scores.

Reference: 1. Burmester GR et al. Ann Rheum Dis. 2017;76:840−847.