Effect of tofacitinib on dactylitis and patient-reported outcomes in patients with active psoriatic arthritis: post-hoc analysis of phase III studies

Background Tofacitinib is an oral Janus kinase inhibitor for the treatment of psoriatic arthritis (PsA). This post-hoc analysis of two phase III studies in patients with PsA treated with tofacitinib assessed dactylitis by location, and the impact on patient-reported outcomes (PROs). Methods Patients received tofacitinib 5 or 10 mg twice daily (BID), or placebo. Endpoints included change from baseline in Dactylitis Severity Score (DSS), proportions of patients with dactylitis, Psoriatic Arthritis Disease Activity Score (PASDAS), and PROs (Health Assessment Questionnaire-Disability Index [HAQ-DI]; Functional Assessment of Chronic Illness Therapy-Fatigue [FACIT-F]; Short Form-36 Health Survey [SF-36] Physical Component Summary [PCS], Mental Component Summary [MCS], and physical functioning [PF]; arthritis pain; and Work Limitations Questionnaire [WLQ]). Descriptive statistics were generated by visit and treatment. Change from baseline in PROs were evaluated by multivariate linear regression. Results The analysis included 373/337 patients with baseline DSS > 0/DSS = 0. Regardless of location, DSS improvements in patients with DSS > 0 were greater from month 1 with tofacitinib (10 mg BID) versus placebo. For patients with DSS > 0/DSS = 0, both doses of tofacitinib led to mean dactylitis presence ≤ 15%/< 2% for all digits at month 6, and PASDAS (by dactylitis location) was lower versus placebo at month 3. Dactylitis location was not significantly associated with change from baseline in PROs. Conclusion Tofacitinib resulted in sustained improvements in dactylitis irrespective of location, with minimal emergence of new dactylitis. Trial registration NCT01877668; NCT01882439