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. Plain Language Summary In many countries, tofacitinib is an approved medicine that can be used to treat psoriatic arthritis (PsA). In the study reported here (OPAL Balance), adult patients with PsA took tofacitinib for up to 3 years. We report a planned interim analysis, i.e., an analysis of information collected before the study finished. This early information suggests that the safety of tofacitinib, and how well it improved symptoms and quality of life (efficacy), was similar in this long study as in shorter studies. Information from the finished study will be reported later. OPAL Balance started on 17 February 2014. This interim analysis includes information collected by 31 August 2017. Before joining, patients had finished a 6-month or 12-month tofacitinib study (OPAL Broaden or OPAL Beyond). Patients in OPAL Balance took a 5 mg tofacitinib pill twice a day, but if PsA symptoms did not improve after 1 month, they could take a 10 mg pill twice a day. They could also take other medicines (including methotrexate or corticosteroids). Of the 686 patients who took tofacitinib, 546 (80%) experienced side effects over 3 years. These were considered serious for 95 patients (14%) and caused 59 patients (9%) to leave the study. Five patients died from causes not related to tofacitinib. Known tofacitinib side effects, including shingles (herpes zoster), serious infections (needing hospitalization), infections in patients with weakened immune systems, cancer, heart (cardiovascular) problems, and vein blockages (embolisms), were each reported by fewer than 20 patients. Most blood test results and tofacitinib efficacy were stable over 2.5 years.