Does baricitinib reduce disease activity in patients with systemic lupus erythematosus? A systematic review and meta-analysis of randomized controlled trials.

Baricitinib is a selective Janus kinase inhibitor that has recently been approved for treating certain autoimmune disorders. This meta-analysis pooled the conflicting results from all published randomized controlled trials (RCTs) about the efficacy and safety of baricitinib in patients with systemic lupus erythematosus (SLE). We systemically searched four electronic databases. RCTs comparing baricitinib versus placebo were included. Our outcomes were pooled as the risk ratio (RR) in the random effects model. Our primary outcome was the proportion of patients who achieved a SLE Responder Index-4 (SRI-4) response. A total of three RCTs, comprising 1849 patients, were included. Baricitinib 4 mg was associated with a significantly higher proportion of patients who attained SRI-4 response at week 24 (RR = 1.19, 95% CI [1.05, 1.35], P < 0.01). However, this did not reach statistical significance with baricitinib 4 mg at week 52 and baricitinib 2 mg at both week 24 and week 52 (RR = 1.13, 95% CI [0.96, 1.34], P = 0.15; RR = 1.09, 95% CI [0.96, 1.24], P = 0.20; RR = 1.05, 95% CI [0.92, 1.19], P = 0.50, respectively). The risk for serious infections was higher in the baricitinib 4 mg group (RR = 2.23, 95% CI [1.13, 4.37], P = 0.02). Baricitinib 2 mg did not show any clinical benefit. In contrast, baricitinib 4 mg might have the potential to reduce SLE disease activity; however, further research is required to evaluate its long-term efficacy. Until higher-quality evidence is developed, the benefits and risks of baricitinib should be considered before initiating its therapy. Key Points • Baricitinib is a selective Janus kinase inhibitor that has recently been approved for treating certain autoimmune disorders; however, its efficacy in patients with systemic lupus erythematosus (SLE) is still inconclusive. • In our meta-analysis, baricitinib 2 mg did not show any clinical benefit. In contrast, baricitinib 4 mg significantly reduced SLE activity in terms of SRI-4 response at week 24. However, this did not reach statistical significance at week 52. • Further studies are required to investigate the long-term efficacy of baricitinib 4 mg in patients with SLE.