Ben Zimmer, CEO of Priovant Therapeutics, discusses results from the recent phase 3 study testing brepocitinib for the treatment of dermatomyositis (DM).
DM is a rare autoimmune condition that causes skin changes and muscle weakness. Symptoms can include a red skin rash around the eyelids, red bumps around the joints, and muscle weakness in the arms and legs. Muscle weakness gets worse over time and can lead to stiff joints and muscle wasting. Current approved treatment options include steroid medications and intravenous immunoglobulin.
Brepocitinib is a dual selective inhibitor of TYK2 and JAK1 administered orally once daily. The medication targets and suppresses the signaling of pathogenic cytokines known to cause disease activity in dermatomyositis. Results from the phase 3 VALOR clinical trial of brepocitinib were recently presented in the New England Journal of Medicine.
The study enrolled a total of 241 patients globally. Subjects were randomized to brepocitinib 30 mg, brepocitinib 15 mg, and placebo, with one-year of double-blind treatment. The primary endpoint was the difference at week 52 between brepocitinib and placebo in mean Total Improvement Score (TIS).
Brepocitinib 30 mg achieved a week 52 mean TIS of 46.5 compared to 31.2 for placebo. A statistically significant difference between brepocitinib 30 mg and placebo on mean TIS was seen at all time points, including as early as week 4. Brepocitinib also demonstrated clinically meaningful and statistically significant improvement over placebo on all nine key secondary endpoints. Dose-dependent response between brepocitinib 30 mg and brepocitinib 15 mg was seen consistently across the primary and secondary endpoints.
Approximately 75% of patients were on background steroids at enrollment, with a mean baseline dose of 12.2 mg/day in the brepocitinib 30 mg arm and 11.3 mg/day in the placebo arm. Of these patients, 62% of brepocitinib 30 mg patients achieved a steroid dose less than or equal to 2.5 mg/day by the end of the study, compared to 34% for placebo. Additionally, 42% of brepocitinib 30 mg patients were able to come off steroids, compared to 23% for placebo.
In the brepocitinib 30 mg arm, clinically meaningful and statistically significant improvements relative to placebo on the CDASI (skin), MMT-8 (motor strength) and HAQ-Disability Index (patient questionnaire around daily living activities requiring functional muscle strength, like getting dressed or walking up five steps) were observed. More than two-thirds of these patients experienced at least a moderate response, and about half experienced a major response. Among patients who entered the trial with moderate-to-severe skin disease, 44% on brepocitinib 30 mg achieved cutaneous clinical remission by week 52, compared to 21% on placebo.
The safety profile of brepocitinib 30 mg was consistent with previous brepocitinib clinical trials. Adverse events of special interest, including malignancy, cardiovascular events, and thromboembolic events, did not occur with greater frequency in the brepocitinib 30 mg arm than the placebo arm.
In March 2026, the US Food and Drug Administration (FDA) accepted the New Drug Application (NDA) for brepocitinib for the treatment of DM and granted the application Priority Review. A Prescription Drug User Fee Act (PDUFA) target action date has been assigned in the third quarter of 2026. The company expects to launch the drug in the United States at the end of September 2026.
To learn more about DM and other rare skin conditions, visit https://checkrare.com/diseases/skin-conditions/