Concert Pharmaceuticals, Inc. announced positive topline results from its second Phase 3 clinical trial, THRIVE-AA2, evaluating its oral investigational medicine CTP-543 in adult patients with moderate to severe alopecia areata, an autoimmune disorder that results in patchy or complete scalp hair loss. The primary efficacy endpoint for THRIVE-AA2 was the percentage of patients achieving an absolute Severity of Alopecia Tool (SALT) score of 20 or less at Week 24 of treatment, which was met with statistical significance in both the 8 mg twice-daily and 12 mg twice-daily dose groups relative to placebo. Treatment with CTP-543 was generally well tolerated.

Patients enrolled in THRIVE-AA2 were required to have at least 50% scalp hair loss due to alopecia areata, as measured by SALT. A SALT score of 100 represents total scalp hair loss, whereas a score of 0 represents no scalp hair loss. The average baseline SALT score across all patients was approximately 87.9 (corresponding to approximately 12% average scalp hair coverage).

A statistically significant proportion of patients treated with either 8 mg twice-daily or 12 mg twice-daily of CTP-543 experienced greater scalp regrowth compared to placebo. The proportion of patients achieving a SALT score of 20 or less (meaning 20% or less scalp hair loss) was 38.3% in the 12 mg twice-daily dose group and 33.0% in the 8 mg twice-daily dose group, compared to 0.8% of patients in the placebo group, at the 24-week endpoint. The treatment difference for both dose groups of CTP-543 relative to placebo was statistically significant (p<0.0001).

The key secondary endpoints were the percentage of responders on a Satisfaction of Hair Patient Reported Outcome (SPRO) scale at Week 24 and the percentage of patients achieving absolute SALT scores of 20 or less at each of Weeks 20, 16, 12 and 8. 47% of patients in the 8 mg twice-daily group and 52% of patients in the 12 mg twice-daily group reported being “satisfied” or “very satisfied,” as compared to 2% of patients in the placebo group. The treatment difference for both groups relative to placebo was statistically significant. SALT scores of 20 or less at Weeks 20, 16 and 12 were statistically significant in both dose groups.

The safety profile seen with CTP-543 in THRIVE-AA2 was consistent with previous studies. The most common (=5%) side effects in any dose group were COVID-19 infection, nasopharyngitis, increased creatine kinase levels, acne and headache. No pulmonary embolisms or deep vein thromboses were observed in the trial.

Two patients treated with the 8 mg twice-daily dose and two patients treated with the 12 mg twice-daily dose developed herpes zoster (shingles). Five serious adverse events were reported in five patients, with only one in the 8 mg twice-daily dose group that was assessed as possibly related to treatment. Concert expects to submit the full results from this study for future scientific publication and presentation.

These data, along with data from the first Phase 3 clinical trial, THRIVE-AA1, are intended to form the basis of a New Drug Application (NDA) planned to be submitted to the U.S. Food and Drug Administration (FDA) in the first half of 2023.