OBJECTIVE: RA patients who have failed biologic DMARDs (bDMARDs) represent an 
unmet medical need. We evaluated the effects of baseline characteristics, 
including prior bDMARD exposure, on baricitinib efficacy and safety.
METHODS: RA-BEACON patients (previously reported) had moderate to severe RA with 
insufficient response to one or more TNF inhibitor and were randomized 1:1:1 to 
once-daily placebo or 2 or 4 mg baricitinib. Prior bDMARD use was allowed. The 
primary endpoint was a 20% improvement in ACR criteria (ACR20) at week 12 for 4 
mg vs placebo. An exploratory, primarily post hoc, subgroup analysis evaluated 
efficacy at weeks 12 and 24 by ACR20 and Clinical Disease Activity Index (CDAI) 
⩽10. An interaction P-value ⩽0.10 was considered significant, with significance 
at both weeks 12 and 24 given more weight.
RESULTS: The odds ratios predominantly favored baricitinib over placebo and were 
generally similar to those in the overall study (3.4, 2.4 for ACR20 weeks 12 and 
24, respectively). Significant quantitative interactions were observed for 
baricitinib 4 mg vs placebo at weeks 12 and 24: ACR20 by region (larger effect 
Europe) and CDAI ⩽10 by disease duration (larger effect ⩾10 years). No 
significant interactions were consistently observed for ACR20 by age; weight; 
disease duration; seropositivity; corticosteroid use; number of prior bDMARDs, 
TNF inhibitors or non-TNF inhibitors; or a specific prior TNF inhibitor. 
Treatment-emergent adverse event rates, including infections, appeared somewhat 
higher across groups with greater prior bDMARD use.
CONCLUSION: Baricitinib demonstrated a consistent, beneficial treatment effect 
in bDMARD-refractory patients across subgroups based on baseline characteristics 
and prior bDMARD use.
TRIAL REGISTRATION: ClinicalTrials.gov (https://clinicaltrials.gov/), 
NCT01721044.