Efficacy and safety of sirukumab in Japanese patients with moderate to severe rheumatoid arthritis inadequately controlled by disease modifying anti-rheumatic drugs: Subgroup analysis of a phase 3 study

Objective: To evaluate the efficacy and safety of sirukumab in Japanese patients with active rheumatoid arthritis (RA) uncontrolled by disease-modifying antirheumatic drugs. Methods: This subgroup analysis based on a double-blind, placebo-controlled, 52-week phase 3 study (SIRROUND-D) assessed American College of Rheumatology (ACR) 20 response at week 16 and van der Heijde-modified Sharp score (vdH-S) at week 52 (coprimary endpoints). Results: A total of 168 (Japanese)/1670 patients received sirukumab 50 mg/4 weeks (q4w, n = 58), 100 mg/every 2 weeks (q2w, n = 54), or placebo (n = 56) subcutaneously. Significantly more patients achieved ACR20 response at week 16 with sirukumab (50 mg q4w: 69.0%; 100mg q2w: 66.7%) vs. placebo (21.4%; p <.001). Median change from baseline in total vdH-S score at week 52 was significantly lower with sirukumab (50 mg q4w: 0.3, p =.024; 100 mg q2w: 0.0, p =.002) vs. placebo (1.3). Sirukumab consistently showed greater improvements in secondary endpoints at weeks 24 and 52. Nasopharyngitis, elevated liver enzymes, injection site erythema and upper respiratory tract infections were the common treatment-emergent adverse events (TEAEs). Incidences of TEAEs and serious AEs were consistent between sirukumab groups through week 52. Conclusion: Sirukumab showed clinically meaningful improvements consistent with significant improvements in the global study. No new safety signals were observed.