Are all JAK inhibitors for the treatment of rheumatoid arthritis equivalent? An adjusted indirect comparison of the efficacy of tofacitinib, baricitinib, upadacitinib, and filgotinib

Introduction Comparisons of Janus kinase inhibitors (JAKi) for treatment of rheumatoid arthritis in patients with inadequate response to biologic disease-modifying anti-rheumatic drugs are lacking. We assessed the relative efficacy and safety of four JAKi (tofacitinib, baricitinib, upadacitinib, and filgotinib) in this context.Method We performed an adjusted indirect comparison (IC) of randomized clinical trials using Bucher's method with an IC and mixed calculator. Endpoints were Disease Activity Score C-reactive protein (DAS28-CRP) and American College of Rheumatology-20 (ACR20). Equivalence was assessed using the equivalent therapeutic alternatives (ETA) guidelines.Results We included four of 133 potentially relevant studies. IC showed no statistically significant differences between the four JAKi regarding DAS28-CRP < 3.2. Results were similar in terms of ACR20 except for tofacitinib showing lower efficacy than upadacitinib (RAR -18.4% [IC95% -33.4 to -3.5], p=0.0157). Statistically significant differences were related to the relevant difference for tofacitinib in both endpoints. Despite no statistical differences for baricitinib, we observed a probably clinically relevant difference regarding DAS28-CRP. Probably clinically relevant differences were found for tofacitinib vs. upadacitinib in both endpoints, and for baricitinib vs. upadacitinib in DAS28-CRP. Safety, drug-drug interactions, and convenience considerations did not modify the result of therapeutic equivalence assessment based on efficacy data.Conclusions In conclusion, our results show that filgotinib and upadacitinib are ETA. Baricitinib and upadacitinib are also ETA due to a lack of clear differences and for showing superiority over placebo. The results for tofacitinib and upadacitinib show some inconsistency and more data are needed.