Comparative effectiveness of biological disease-modifying antirheumatic drugs and Janus kinase inhibitor monotherapy in rheumatoid arthritis

To examine the effectiveness and drug tolerability of biological disease-modifying antirheumatic drugs (bDMARDs) and Janus kinase inhibitor (JAKi) monotherapy in patients with rheumatoid arthritis (RA) in a multicentre cohort study.Patients with RA initiated with bDMARD/JAKi monotherapy without conventional synthetic DMARDs were included. Monotherapy regimens were categorised as interleukin-6 receptor inhibitors (IL-6Ri), cytotoxic T-lymphocyte-associated protein 4 immunoglobulin (CTLA4Ig), JAKi, or tumour necrosis factor inhibitors (TNFi). Multiple propensity score-based inverse probability weighting (IPW) was used to reduce selection bias. Linear mixed-effect models with IPW were used to examine changes in the disease activity score in 28 joints (DAS28)-erythrocyte sedimentation rate (ESR) at 24 weeks, and drug retention was compared among monotherapy using IPW Cox proportional hazards models.A total of 849 treatment courses from 635 patients were included (IL-6Ri, 218; CTLA4Ig, 183; JAKi, 92; TNFi, 356). The difference in change in DAS28-ESR at week 24 as the primary outcome was -0.93 (95% CI: -1.20 to -0.66) lower in the IL-6Ri group than TNFi, while that of CTLA4Ig and JAKi was similar with that of TNFi (-0.20 [-0.48 to 0.08], -0.25 [-0.67 to 0.16], respectively). IL-6Ri use was associated with significantly lower overall drug discontinuation than TNFi use (hazard ratio = 0.55 [0.39-0.78], P = 0.001). Similar retention rates were identified among CTLA4Ig and JAKi compared to TNFi.In the analysis with IPW to reduce selection bias, IL-6Ri monotherapy was superior to TNFi monotherapy in terms of effectiveness and drug retention. No significant differences were identified between CTLA4Ig, JAKi, and TNFi monotherapy.