Background: Alopecia areata is an autoimmune condition characterized by rapid hair loss in the scalp, eyebrows, and eyelashes, for which treatments are limited. Baricitinib, an oral, selective, reversible inhibitor of Janus kinases 1 and 2, may interrupt cytokine signaling implicated in the pathogenesis of alopecia areata.

Methods: We conducted two randomized, placebo-controlled, phase 3 trials (BRAVE-AA1 and BRAVE-AA2) involving adults with severe alopecia areata with a Severity of Alopecia Tool (SALT) score of 50 or higher (range, 0 [no scalp hair loss] to 100 [complete scalp hair loss]). Patients were randomly assigned in a 3:2:2 ratio to receive once-daily baricitinib at a dose of 4 mg, baricitinib at a dose of 2 mg, or placebo. The primary outcome was a SALT score of 20 or less at week 36.

Results: We enrolled 654 patients in the BRAVE-AA1 trial and 546 in the BRAVE-AA2 trial. The estimated percentage of patients with a SALT score of 20 or less at week 36 was 38.8% with 4-mg baricitinib, 22.8% with 2-mg baricitinib, and 6.2% with placebo in BRAVE-AA1 and 35.9%, 19.4%, and 3.3%, respectively, in BRAVE-AA2. In BRAVE-AA1, the difference between 4-mg baricitinib and placebo was 32.6 percentage points (95% confidence interval [CI], 25.6 to 39.5), and the difference between 2-mg baricitinib and placebo was 16.6 percentage points (95% CI, 9.5 to 23.8) (P<0.001 for each dose vs. placebo). In BRAVE-AA2, the corresponding values were 32.6 percentage points (95% CI, 25.6 to 39.6) and 16.1 percentage points (95% CI, 9.1 to 23.2) (P<0.001 for each dose vs. placebo). Secondary outcomes for baricitinib at a dose of 4 mg but not at a dose of 2 mg generally favored baricitinib over placebo. Acne, elevated levels of creatine kinase, and increased levels of low- and high-density lipoprotein cholesterol were more common with baricitinib than with placebo.

Conclusions: In two phase 3 trials involving patients with severe alopecia areata, oral baricitinib was superior to placebo with respect to hair regrowth at 36 weeks. Longer trials are required to assess the efficacy and safety of baricitinib for alopecia areata. (Funded by Eli Lilly under license from Incyte; BRAVE-AA1 and BRAVE-AA2 ClinicalTrials.gov numbers, NCT03570749 and NCT03899259.).