Baricitinib May Exhibit Better Efficacy Than Adalimumab for RA

Baricitinib, an investigational, oral, reversible inhibitor of Janus kinases JAK1 and JAK2, has completed the RA-BEAM, Phase 3 clinical trial.¹ This study was a 52-week, randomized, double-blind, placebo- and active-controlled, parallel-group trial conducted in 26 countries.

Participants (n=1,307) were randomized into groups (3:3:2) to receive placebo, 4 mg baricitinib once daily or 40 mg of subcutaneous adalimumab every other week. Patients also continued background therapy with conventional synthetic disease-modifying anti-rheumatic drugs (DMARDs), non-steroidal anti-inflammatory drugs (NSAIDs), analgesics or glucocorticoids (≤10 mg prednisone or the equivalent per day). Placebo patients were switched to baricitinib at Week 24, maintaining study blinding. Most patients received background methotrexate (>99%) and the majority of patients had previously received at least two conventional synthetic DMARDs. The ACR20 response at Week 12 was the primary endpoint. Secondary endpoints included measurement of the DAS28, the health assessment questionnaire-disability index (HAQ-DI) and the Simplified Disease Activity Index (SDAI). The modified total Sharp score (mTSS) at Week 24 was also a secondary endpoint.

At Week 12, more baricitinib-treated patients had an ACR20 response compared with placebo-treated patients (70% vs. 40%, P<0.001). All of the secondary endpoints improved for the baricitinib-treated patients compared with placebo-treated patients, including the mTSS at Week 24. In the active-controlled treatment group receiving adalimumab, 61% of patients achieved ACR20 at Week 12 compared with 70% of baricitinib-treated patients. Baricitinib was deemed to be noninferior to adalimumab at Week 12 for the ACR20 response. At Week 52, a higher proportion of baricitinib-treated patients achieved ACR50 and ACR70 compared with adalimumab-treated patients.

Rates of study discontinuation due to adverse events were relatively low from baseline to Week 24. Discontinuation rates were 3% for placebo-treated patients, 5% for baricitinib and 2% for adalimumab. Serious adverse event rates through Week 24 were 5%, 5% and 2% for placebo, baricitinib and adalimumab, respectively. Through Week 52, serious adverse events occurred in 8% of baricitinib-treated patients and 4% of adalimumab-treated patients. Baricitinib-treated patients (71%) and adalimumab-treated patients (68%) had more frequent adverse events than placebo-treated patients (60%). Infection rates in baricitinib-treated patients (48%) and adalimumab-treated patients (44%) were similar through Week 52.

An adalimumab-treated patient developed tuberculosis. Cancers occurred in five patients (n=2 baricitinib-treated patients; n=3 placebo-treated patients). Baricitinib was also associated with neutrophil count lowering, creatinine increases and low-density lipoprotein cholesterol increases. Five deaths were also reported (n=2 for baricitinib; n=1 for placebo to baricitinib; n=1 for adalimumab; and n=1 for placebo).