Safety and Efficacy of Tofacitinib in Patients with Active Psoriatic Arthritis: Interim Analysis of OPAL Balance, an Open-Label, Long-Term Extension Study

Introduction: Tofacitinib is an oral Janus kinase inhibitor for the treatment of psoriatic arthritis (PsA). We report the interim safety, tolerability, and efficacy of tofacitinib in PsA patients in OPAL Balance, a 3-year, open-label, long-term extension study (data cut-off: August 2017; database not locked, data may change).

Methods: Eligible patients from two phase (P) 3 (P3) tofacitinib PsA studies (OPAL Broaden, NCT01877668; OPAL Beyond, NCT01882439) entered OPAL Balance ≤ 3 months after completing the P3 study or discontinuing for reasons other than study-drug-related adverse events (AEs). Patients received open-label tofacitinib 5 mg twice daily (BID), with adjustments to 10 mg BID permitted post-month (M) 1. Certain concomitant conventional synthetic disease-modifying antirheumatic drugs were allowed. Primary endpoints were incidence/severity of AEs and laboratory abnormalities, and changes from baseline in laboratory parameters (reported up to M36 and M30, respectively). Efficacy (clinical/patient-reported outcomes) was reported through M30.

Results: A total of 686 patients were treated; at data cut-off, 68.2% remained in the study. Mean (range) treatment duration was 641 (1-1032) days; total treatment duration was 1153.2 patient-years. By M36, 79.6, 13.8, and 8.6% of patients reported AEs, serious AEs, and discontinuations due to AEs, respectively. Five deaths occurred; one within the risk period (incidence rate [IR; patients with events/100 patient-years] 0.1). IRs for AEs of special interest were: all (non-serious and serious) herpes zoster, 1.7; serious infections, 0.9; opportunistic infections, 0.3 (all disseminated/multi-dermatomal herpes zoster); malignancies excluding non-melanoma skin cancer (NMSC), 0.8; NMSC, 1.0; major adverse cardiovascular events, 0.3; pulmonary embolisms, 0.1; and arterial thromboembolisms, 0.4. No patients had deep vein thrombosis. Alanine aminotransferase and aspartate aminotransferase levels were elevated  ≥  3-fold the upper limit of normal in 4.0 and 2.2% of patients, respectively. Changes in laboratory parameters were generally stable over time, although lymphocyte counts decreased slightly. Efficacy was maintained through M30.

Conclusions: In this interim analysis of OPAL Balance, tofacitinib safety and efficacy in patients with PsA appeared to be consistent with those of the P3 studies. Efficacy was maintained over time.

Trial Registration: ClinicalTrials.gov identifier: NCT01976364.