Efficacy and safety of tofacitinib versus baricitinib in patients with rheumatoid arthritis in real clinical practice: analyses with propensity score-based inverse probability of treatment weighting.

Objectives The differences of efficacy between each Janus kinase (JAK) inhibitors have not been clarified in the patients with rheumatoid arthritis (RA) in clinical practice. Here, we compared the efficacy between tofacitinib (TOFA) and baricitinib (BARI) in clinical practice. Methods The efficacy of TOFA (n=156) in patients with RA was compared with BARI (n=138). Selection bias was reduced to a minimum using propensity score-based inverse probability of treatment weighting (IPTW). The Clinical Disease Activity Index (CDAI) trajectory for patients who started TOFA or BARI was analysed using growth mixture modelling (GMM). Results No significant difference was observed in patient characteristics between the TOFA and BARI groups in after adjustment by propensity score-based IPTW. The BARI group had a significantly higher rate of CDAI remission at week 24 after the introduction of JAK inhibitors than the TOFA group. The treatment-resistant group defined by GMM, comprising patients who did not achieve low disease activity at week 24, was more likely to include those who had received many biological disease-modifying antirheumatic drugs (bDMARDs) before the introduction of JAK inhibitors and those who received TOFA. Among patients with RA who received TOFA, those who had received ≥4 bDMARDs before the introduction of TOFA were more likely to be classified into the treatment-resistant group. Conclusions BARI showed a similar safety profile and better clinical outcome when compared with TOFA after reduction to a minimum of selection bias. However, these were observed in a small population. Accordingly, further investigation is required in an accurately powered head-to-head trial.