Background/Purpose : The efficacy of some rheumatoid arthritis (RA) therapies is reduced among patients with high BMI. This analysis assessed the effects of baseline BMI on the response to baricitinib treatment in patients with RA and incomplete responses to conventional disease-modifying antirheumatic drugs (cDMARDs).

Methods: This post hoc analysis used pooled data from two phase 3, double-blind, randomized, controlled trials of 6-12 months’ duration in patients with RA and an incomplete response to cDMARDs. Efficacy outcomes (e.g., ACR responses, and changes in DAS28-hsCRP, HAQ-DI, SDAI, and CDAI scores) were analyzed by baseline patient BMI tertile (calculated from height and weight measurements at screening).

Results: In all BMI tertiles, patients who received baricitinib 4-mg (n=714) achieved improved clinical outcomes compared to those who received placebo (n=716) in efficacy measures including ACR20, ACR50 and ACR70, mean change in DAS28, SDAI, and CDAI, as well as the proportions of patients who reached low disease activity or remission (Table). No clear pattern emerged to suggest that baseline BMI tertile had a consistent effect on baricitinib efficacy. For some outcomes (e.g., ACR responses), a numeric trend toward reduced efficacy was observed among patients with greater BMI who received baricitinib 4-mg (Table).

Conclusion: Post hoc analysis of these pooled RA trial data suggests that baricitinib therapy is associated with improved clinical outcomes compared to placebo, regardless of baseline patient BMI tertile. As has been shown for other DMARDs, baricitinib treatment effect for patients with higher BMI was numerically smaller than for patients with lower BMI.