Baricitinib plus Standard of Care for Hospitalized Adults with COVID-19

Background: Baricitinib, an oral selective Janus kinase 1 and 2 inhibitor, improved outcomes in a previous randomized controlled trial of hospitalized adults with COVID-19, in combination with remdesivir. Methods: In this phase 3, global, double-blind, randomized, placebo-controlled trial, 1525 hospitalized adults with COVID-19 receiving standard of care (SOC) were randomly assigned (1:1) to once-daily baricitinib 4-mg (N=764) or placebo (N=761) for up to 14 days. SOC included systemic corticosteroids in ~79% of participants (dexamethasone ~90%). The primary endpoint was the proportion who progressed to high-flow oxygen, non-invasive ventilation, invasive mechanical ventilation, or death by day 28. A key secondary endpoint was all-cause mortality by day 28. Results: Overall, 27.8% of participants receiving baricitinib vs 30.5% receiving placebo progressed (primary endpoint, odds ratio 0.85, 95% CI 0.67-1.08; p=0.18). The 28-day all-cause mortality was 8.1% for baricitinib and 13.1% for placebo, corresponding to a 38.2% reduction in mortality (hazard ratio [HR] 0.57, 95% CI 0.41-0.78; nominal p=0.002); 1 additional death was prevented per 20 baricitinib-treated participants. Reduction in mortality was seen for all pre-specified subgroups of baseline severity (most pronounced for participants on high-flow oxygen/non-invasive ventilation at baseline [17.5%, baricitinib vs 29.4%, placebo; HR 0.52, 95% CI 0.33-0.80; nominal p=0.007]). The frequency of adverse events, serious adverse events, serious infections, and venous thromboembolic events was similar between groups. Conclusions: While reduction of disease progression did not achieve statistical significance, treatment with baricitinib in addition to SOC (predominantly dexamethasone) significantly reduced mortality with a similar safety profile between groups of hospitalized COVID-19 participants.