Study Investigating Oral JAK Inhibitor for Alopecia Areata Meets Endpoint

CTP-543 is an investigational oral selective inhibitor of JAK1 and JAK2.

Positive topline results were announced from a second phase 3 trial evaluating the efficacy and safety of CTP-543 in adults with moderate to severe alopecia areata.

CTP-543 is an investigational oral selective inhibitor of Janus kinases 1 (JAK1) and JAK2. The randomized, double-blind, placebo-controlled THRIVE-AA2 trial ( Identifier: NCT04797650) included 517 adults aged 18 to 65 years with moderate to severe alopecia areata who had at least 50% scalp hair loss, as measured by Severity of Alopecia Tool (SALT) score. Patients were randomly assigned to receive CTP-543 8mg or 12mg orally twice daily or placebo for 24 weeks.

The primary endpoint was the percentage of patients achieving an absolute SALT score of 20 or less at week 24. SALT is an assessment of scalp hair loss with scores ranging from 0 (no scalp hair loss) to 100 (complete scalp hair loss). The average baseline SALT score was approximately 87.9 for all patients.

Results showed that 33.0% and 38.3% of patients treated with CTP-543 8mg and 12mg, respectively, achieved a SALT score of 20 or less, compared with 0.8% of patients who received placebo (treatment difference for both dose groups: P <.0001).

Additionally, both doses of CTP-543 were associated with statistically significant improvements in key secondary endpoints, including the percentage of responders on a Satisfaction of Hair Patient Reported Outcome scale at week 24 and the percentage of patients achieving absolute SALT scores of 20 or less at weeks 8, 12, 16, and 20. There were 47% and 52% of patients treated with CTP-543 8mg and 12mg, respectively, who reported being “satisfied” or “very satisfied” compared with 2% of patients who received placebo; the treatment difference for both dose groups was statistically significant.

The safety profile of CTP-543 was consistent with that observed in previous studies. The most common adverse reactions reported in the CTP-543 dose groups were COVID-19 infection, nasopharyngitis, increased creatine kinase levels, acne, and headache.

Full study results will be submitted for future scientific publication and presentation. Data from the phase 3 THRIVE-AA2 and THRIVE-AA1 ( Identifier: NCT04518995) trials are intended to support the Company’s New Drug Application submission to the Food and Drug Administration (FDA) in the first half of 2023.

“Based on the results from our phase 3 program, we believe CTP-543, if approved, could be a best-in-class treatment option for alopecia areata and have a distinct therapeutic profile with features that are important to patients, including the percentage of patients with clinically-meaningful hair regrowth, patient satisfaction levels, and hair regrowth rates,” said James V. Cassella, PhD, Chief Development Officer of Concert Pharmaceuticals.


Concert Pharmaceuticals reports positive topline results for second CTP‑543 phase 3 clinical trial in alopecia areata. News release. Concert Pharmaceuticals, Inc. Accessed August 1, 2022.

This article originally appeared on MPR