Long-term safety and efficacy of E6011, an anti-fractalkine monoclonal antibody, in patients with rheumatoid arthritis inadequately responding to methotrexate

Objectives: To evaluate the long-term safety and efficacy of E6011, a humanized anti-fractalkine monoclonal antibody, in patients with rheumatoid arthritis (RA) with an inadequate response to methotrexate (MTX).

Methods: Active RA patients with an inadequate response to MTX were randomly assigned to the E6011 or placebo group and received the study drug subcutaneously every 2 weeks during a 24-week double-blind study period. Subjects who completed evaluations at Week 24 were rolled over into the extension phase and received open-label E6011 (200 or 400 mg) every 2 weeks until Week 102. The safety analysis was conducted up to Week 104, and the efficacy analysis was conducted up to Week 84.

Results: A total of 169 subjects completed the double-blind treatment phase and were rolled over into the extension phase. In total, 167 (98.8%) subjects experienced any adverse events, and the incidence of treatment-related adverse events was 56.2%. The American College of Rheumatology 20 response rates were observed between 40 and 70% during the extension phase.

Conclusions: E6011 was safe and well tolerated with no notable safety concerns up to 102 weeks in RA patients with an inadequate response to MTX.