The activation of Janus kinase (JAK) is thought to play a pathogenic role in alopecia areata (AA). As an oral therapy for AA, CTP-543, a deuterated drug that specifically inhibits JAK1 and JAK2, was being investigated. For a study, researchers sought to evaluate the safety and effectiveness of a 24-week CTP-543 regimen in patients with chronic, moderate-to-severe AA.

Patients were randomly assigned to receive CTP-543 (4 mg, 8 mg, or 12 mg) or placebo every 12 hours for 24 weeks in this phase 2 randomized, double-blind, placebo-controlled, sequential-design experiment.

At week 24, a dose-related increase in the percentage of patients with a 50% relative reduction in Severity of Alopecia Tool scores from baseline was observed (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 start of treatment. The safety results were consistent with established JAK inhibitor safety characteristics. The preliminary data come from a limited controlled trial, and further research is needed to completely assess CTP-543’s safety and effectiveness in adult patients with AA.

CTP-543 (8 or 12 mg twice daily) significantly reduced the severity of AA in patients.