A pooled safety analysis of peficitinib (ASP015K) in Asian patients with rheumatoid arthritis treated over a median of 2 years

Objective: To evaluate the safety of peficitinib for the treatment of rheumatoid arthritis (RA) in Asian patients. Methods: Safety data from one Phase 2b, two Phase 3, and one open-label long-term extension study [data cut-off 31 May 2018] were pooled into Phase 3 studies (peficitinib 100 and 150 mg/day, and placebo) and Phase 2/3 studies (all peficitinib-treated patients). Incidence rates per 100 patient-years (PY) of adverse events (AEs) of special interest were calculated. Results: Overall, 1052 patients received peficitinib for 2336.3 PY of exposure (median 2.1 years); four deaths occurred, including one death after the studies. AE incidence was similar across peficitinib 100 and 150 mg/day groups (Phase 3 studies). Respective peficitinib and placebo incidence rates (95% confidence interval) per 100 PY were 2.9 (1.9, 4.6) and 0.0 for serious infections, 5.7 (4.2, 7.9) and 2.3 (0.6, 9.4) for herpes zoster-related disease, and 0.6 (0.2, 1.6) and 1.2 (0.2, 8.3) for malignancies (excluding non-melanoma skin cancer) (Phase 3 studies), and 0.1 (0.0, 0.3) for venous thromboembolism in all peficitinib-treated patients (Phase 2/3 studies). Conclusion: Peficitinib was well tolerated in Asian patients with RA over a median of 2 years, with no observed dose or temporal dependency for AEs with prolonged administration.