Safety of JAK inhibitors versus other biologic therapies following anti-TNF failure in patients with rheumatoid arthritis

Background: Treatment of rheumatoid arthritis (RA) frequently requires Janus kinase inhibitors (JAKi) and biologic DMARDs (bDMARDs) with other mechanisms of action (OMA) after tumour necrosis factor inhibitors (TNFi) failure. Comparative safety data between JAKis and OMA in TNFi-inadequate responders (TNFi-IR) remain limited. Objectives: To evaluate and compare safety profiles of JAKis versus OMA in TNFi-IR RA patients. Methods: A retrospective cohort study followed 305 RA patients (163 JAKis; 142 OMA) previously treated with TNFi for up to 24 months. Incidence rates (IR) of adverse events (AEs) per 100 patient-years (PY) and incidence rate ratios (IRR) adjusted for disease activity and previous bDMARD exposure were calculated using Poisson regression. Results: At baseline, OMA patients had higher disease activity (DAS28-CRP = 4.5 vs. 3.8), whereas comorbidities and other baseline characteristics were similar. Overall, AE incidence was higher with OMA (IR 111.6/100 PY) compared to JAKis (IR 65.3/100 PY; adjusted IRR 1.67, 95% CI 1.22–2.31). Serious AEs occurred more frequently with OMA (IR 11.7/100 PY) versus JAKis (IR 7.9/100 PY; adjusted IRR 0.41, 95% CI 0.18–0.95). Infection rates were comparable; herpes zoster occurred exclusively in the JAKi group during the initial year. Venous thromboembolism, cardiovascular events, and malignancies were rare and similar between groups. Conclusion: In RA patients with inadequate response to TNFis, JAKis and OMA showed comparable safety profiles over 24 months. Serious AEs were numerically higher with OMA; herpes zoster was more frequent with JAKis. No new significant safety signals emerged.