Ann Rheum Dis 2017;76:88–95.Baricitinib improved symptoms of RA in the RA-BUILD trial, a Phase 3 study of baricitinib in patients with moderately to severely active RA, refractory to or intolerant to csDMARDs. As well as providing a short-term (24 weeks) benefit, there appeared to be joint damage benefit, considered a marker of long-term disability.RA-BUILD was a 24-week randomised, double-blind, placebo-controlled parallel-group study. Patients were randomised 1:1:1 to receive once-daily doses of placebo (n=228) or baricitinib 2- (n=229) or 4 mg (n=227) added to any stable background therapies. The primary endpoint was ACR20 response at Week 12 (baricitinib 4 mg vs placebo). Secondary measures included: HAQ-DI, DAS28-CRP, SDAI ≤3.3, and radiographic progression at Week 24.At Week 12, ACR20 response rate for baricitinib 4 mg was 62%, versus 39% for placebo (P≤0.001). Statistically significant improvements in HAQ-DI, DAS28-CRP and SDAI ≤3.3 were also seen at Week 12 for both baricitinib doses versus placebo, and a statistically significant reduction in radiographic progression from baseline to Week 24 versus placebo.These findings suggest baricitinib is an effective therapy for treating the signs and symptoms of RA, with 4 mg the more effective dose. Studies in different populations, in addition to long-term exposure, are needed to further explore its safety and long-term efficacy.