Phase 2 randomized, dose-ranging trial of CTP-543, a selective Janus Kinase inhibitor, in moderate-to-severe alopecia areata.

<bold>Background: </bold>Janus kinase (JAK) activation is suggested to have a pathological role in alopecia areata (AA). CTP-543, a deuterated compound that selectively inhibits JAK1 and JAK2, is being developed as an oral treatment for AA.<bold>Objective: </bold>To assess the safety and efficacy of a 24-week regimen of CTP-543 in patients with chronic, moderate-to-severe AA.<bold>Methods: </bold>In this phase 2, randomized, double-blind, placebo-controlled, sequential-design trial, patients were randomized to receive CTP-543 (4 mg, 8 mg, or 12 mg) or placebo every 12 hours for 24 weeks.<bold>Results: </bold>A dose-related increase was observed in the percentage of patients with ≥50% relative reduction in Severity of Alopecia Tool scores from baseline at week 24 (9% placebo, 21% 4 mg twice daily, 47% 8 mg twice daily, and 58% 12 mg twice daily), with statistical significance versus placebo (P < .001) observed for the 8-mg twice daily and 12-mg twice daily groups, with differences from placebo noted as early as 12 weeks after the initiation of treatment. Safety results were consistent with the known safety profiles of JAK inhibitors.<bold>Limitations: </bold>These initial findings are from a relatively small controlled trial, and additional studies are needed to fully characterize the safety and efficacy of CTP-543 in adult patients with AA.<bold>Conclusions: </bold>Patients treated with CTP-543 (8 or 12 mg, twice daily) had a significant reduction in the severity of AA. [ABSTRACT FROM AUTHOR]