Efficacy and safety of tabalumab plus standard of care in Japanese patients with active systemic lupus erythematosus: Subgroup analyses of the ILLUMINATE-1 study

Objective: To assess the efficacy and safety of tabalumab, an anti-B cell activating factor (BAFF) antibody, in combination with standard of care (SoC) therapy in Japanese patients with active systemic lupus erythematosus (SLE). Methods: A subgroup analysis was conducted in Japanese patients (n = 45) enrolled in ILLUMINATE-1, a phase III global trial in SLE patients (N = 1164). Patients received SoC plus tabalumab or placebo, starting with a loading dose (240 mg) at week 0, followed by 120 mg every 4 weeks (120 Q4W, n = 15), 120 mg every 2 weeks (120 Q2W, n = 15), or placebo Q2W (n = 15). The primary endpoint was proportion achieving SLE Responder Index-5 (SRI-5) improvement at week 52. Results: A numerically greater SRI-5 response rate was achieved with 120 Q2W (46.7%; p = 0.059 vs. placebo) compared with 120 Q4W (20.0%) and placebo Q2W (13.3%). The proportion of patients with severe SLE flare was lower for 120 Q2W (0%) and 120 Q4W (6.7%) than for placebo (26.7%). The rates of serious adverse events (AEs) and treatment-emergent AEs were similar across treatments. Conclusion: In Japanese SLE patients, tabalumab 120 Q2W improved SRI-5 response rate and reduced the frequency of severe flares compared with placebo. Safety profiles were similar with tabalumab and placebo.