A rare disease, a good result: Researchers report positive Phase 3 trial results for a treatment for dermatomyositis | AAD 2026

Researchers reported positive results for a novel agent for dermatomyositis from a Phase 3 trial today at the 2026 American Academy of Dermatology Annual Meeting in Denver. The results were published simultaneously in the New England Journal of Medicine (NEJM).

“If you had asked me when I started practicing almost 20 years ago if we would ever have a pivotal Phase 3, global, randomized controlled trial in dermatomyositis, I don’t know if I would have believed it,” co-lead author Ruth Ann Vleugels, M.D., M.P.H., MBA, a professor of dermatology at Harvard Medical School and director of Connective Tissue Disease Clinics at Harvard-affiliated Brigham and Women’s Hospital, said in an interview with Managed Healthcare Executive. Brepocitinib, the agent assessed in the trial, is an oral drug that inhibits Janus kinase 1 (JAK1) and tyrosine kinase 2 (TYK2), a duality that explains its efficacy because it stifles multiple cytokines implicated in the pathogenesis of dermatomyositis in addition to interferon 1 and 2, Vleugels said.

The FDA has put brepocitinib in a category that is supposed to mean a speedier review process. Priovant Therapeutics, the Durham, North Carolina, company that developed brepocitinib, says its product has a Prescription Drug User Fee Act (PDUFA) date — the date on which the FDA is supposed to make a decision on whether to approve a drug — in the third quarter of this year.

The results reported in the NEJM showed positive results on the trial’s primary end point for the 30-milligram (mg) dose of brepocitinib, but the other dose assessed in the trial, 15 mg, fell short of producing a statistically significant difference. Vleugels, a consultant to Priovant, said the difference between the 30-mg and the 15-mg dose was indicative of a dose-response relationship, a favorable sign of efficacy. “When you look at the graphs, there’s actually a nice separation from placebo [with] the 15 [mg dose] and then also between the 15 and 30 [mg dose],” she said.

Close to 10% (9.95) of the patients randomly assigned to the 30-mg dose of brepocitinib experienced a serious infection during the yearlong trial, compared with 2.5% of the patients assigned to the 15-mg dose and 1.3% in the placebo group. Vleugels noted that brepocitinib was “layered on” other treatments.

“For those who are experts in dermatomyositis, this would be something we would expect. The more therapies you lay on, you have to be mindful of infections,” she said. Vleugels noted that the vast majority of the patients who experienced a serious infection were able to continue taking brepocitinib.

‘Worse impact’

Dermatomyositis is an inflammatory muscle disease that also affects the skin and sometimes the lungs. Muscle weakness is one of the main symptoms, although by some accounts, 40% of patients experience only the dermatological symptoms, which include Gottron papules, which are red, purple or dark bumps that appear on the knuckles, elbows or knees. Vleugels says the itch from dermatomyositis “can be incredibly impactful.”

“We have patients who literally can’t stop scratching. They can’t go to work. They can’t function because of their severe skin disease,” she said. The muscle weakness from dermatomyositis can be so severe that people can’t get out of a chair or bed on their own, said Vleugels.

“This disease has a worse impact on the quality of life of patients [than] almost any disease we study,” said Vleugels.

Several sources cite a prevalence of one case per every million people. If that is accurate, it would mean there are approximately 3,400 cases in the U.S. Vleugels says dermatomyositis may be underdiagnosed and that a new treatment may mean more cases will be diagnosed. Dermatologists are often the primary physicians for people with dermatomyositis because of the dermatologic symptoms, she said, but rheumatologists and pulmonologists are also involved in the care of people with the condition.

Good results on secondary end points

Vleugels and her colleagues enrolled 241 patients in the Phase 3 trial, dubbed VALOR, at 90 sites in 20 countries, according to their NEJM article. The researchers randomly assigned a nearly equal number of patients to the 30-mg dose of brepocitinib (81 patients), the 15-mg dose (81 patients) and the placebo (79 patients). The primary end point was a composite of six measures of myositis activity called the Total Improvement Score. Vleugels said that score has been used in other studies of treatments for dermatomyositis and that it encompasses both the muscle and skin aspects of the disease. The trial design called for a treatment period of 52 weeks. The majority (87.1% [210 of 241]) of the patients finished the treatment period.

At the 52-week mark, the average Total Improvement Score for the patients in the 30-mg group was 46.5, compared with 37.5 in the 15-mg group and 31.2 in the placebo group. Vleugels and her colleagues reported that 41.7% of the patients randomly assigned to 30 mg of brepocitinib tapered their use of systemic corticosteroids and were not taking corticosteroids at the end of the 52-week treatment, compared with 23.4% in the placebo group.

In her interview with MHE and in the NEJM study with her colleagues, Vleugels noted that the patients in the 30-mg group showed improvement on all the secondary end points, which included patient-reported assessments of muscle strength and physical function.

“I think the fact that this was positive on all of the prespecified [secondary] end points shows that [brepocitinib] really has this impact on those multifaceted aspects of this disease. I think that’s why my colleagues who are myositis experts and I are so excited by this therapy,” Vleugels said.