The effectiveness of tofacitinib, a novel Janus kinase inhibitor, in the treatment of rheumatoid arthritis: a systematic review and meta-analysis

The aim of the present study was to conduct a meta-analysis of the effectiveness of tofacitinib, a novel oral Janus kinase inhibitor, recently approved for the treatment of active rheumatoid arthritis in patients who have failed previous treatment with methotrexate (MTX) or other disease-modifying antirheumatic drugs (DMARDs). A systematic literature search was conducted in PubMed, EMBASE, Cochrane Library, and other databases till 3 May 2013. All included studies were analyzed with the use of the Review Manager 5.1.0. software according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) Statement protocol. Nine randomized controlled trials (RCTs) comparing tofacitinib with placebo were identified. Two of them additionally provided the comparison with adalimumab. However, only eight RCTs met the inclusion criteria for the meta-analysis. The overall results of the meta-analysis showed that tofacitinib provided a statistically significant improvement according to the response criteria (ACR20/50/70) after 12 weeks of treatment when compared to placebo (p < 0.00001). Moreover, it was demonstrated that tofacitinib was significantly superior to adalimumab in achieving the ACR50 response criteria at week 12 (p = 0.003). For the safety analysis, there were no statistically significant differences between tofacitinib-, adalimumab-, and placebo-treated patients in respect to the risk of serious adverse events or treatment discontinuation due to adverse reactions (p > 0.05). The findings of this systematic review with meta-analysis indicate that tofacitinib monotherapy or with background methotrexate provides early statistically significant and clinically important improvement in rheumatoid arthritis symptoms and has an acceptable safety profile comparable to that of placebo. The results of the present meta-analysis show that the frequency of serious adverse events was not increased after tofacitinib treatment. In addition, tofacitinib might provide an effective treatment option compared to intravenous or subcutaneous biological DMARDs, as suggested by the result of the comparison made regarding tofacitinib vs. adalimumab ACR50 response rate.