Long-term safety and efficacy of olokizumab in patients with rheumatoid arthritis and inadequate response to tumor necrosis factor inhibitor therapy in phase II studies.

Objective: This study aimed to evaluate the long-term safety and efficacy of olokizumab (OKZ), an anti-interleukin (IL)-6 monoclonal antibody, in patients with rheumatoid arthritis (RA) and inadequate response to tumor necrosis factor-alpha inhibitors.

Methods: Eligible patients completed study RA0056, which tested several doses of OKZ, placebo (PBO), and tocilizumab (TCZ) plus methotrexate (MTX) in Western countries, and RA0083 included several doses of OKZ and PBO plus MTX in Asian countries. Both studies were followed by open-label extension (OLE) studies with OKZ 120 mg every 2 weeks, RA0057 and RA0089, respectively. Safety assessments were reported up to 124 weeks in RA0057 and 92 weeks in RA0089. Efficacy assessments were reported up to week 60 in RA0057 and week 52 in RA0089. No formal statistical hypothesis testing was performed, and missing data were not imputed.

Results: A total of 190 patients in RA0057 and 103 patients in RA0089 received OKZ with median treatment duration of 14.1 and 10.1 months, respectively. Serious adverse events (SAEs) were reported in 44 patients (23.2%, 32.7 events per 100 patient-years [PY]) in RA0057 and in 13 patients (12.6%, 23.6 events per 100 PY) in RA0089. Among treatment-emergent adverse events (TEAEs), including SAEs, infections were the most common events. TEAEs leading to withdrawal were reported in 33 (17.4%) patients in RA0057 and in 7 (6.8%) patients in RA0089. Disease activity score 28-joint count on the basis of C-reactive protein level, clinical disease activity index, and simplified disease activity index, as well as the American College of Rheumatology 20%, 50%, and 70% response rates were maintained during the OLE studies, including in those who switched from PBO or TCZ. Improvements in patient-reported outcomes were maintained in OLEs as well.

Conclusion: In the 2 long-term studies, OKZ treatment demonstrated a safety profile expected for IL-6 blocking agents without new safety signals and led to sustained improvements in RA symptoms, physical function, and quality of life.