First Targeted Therapy for Dermatomyositis Succeeds in Landmark 52-Week Trial, Published in NEJM With FDA Priority Review
Brepocitinib, a first-in-class TYK2/JAK1 inhibitor, hit all primary and secondary endpoints in the largest-ever dermatomyositis trial, offering the first steroid-sparing treatment for a disease that has lacked targeted therapy for decades.
Overview
The New England Journal of Medicine published results on March 28 from the Phase 3 VALOR trial showing that brepocitinib, a first-in-class oral TYK2/JAK1 inhibitor, achieved statistically significant improvements across every primary and secondary endpoint in adults with dermatomyositis, according to Priovant Therapeutics. The U.S. Food and Drug Administration has granted Priority Review to the drug’s New Drug Application, with a target action date in the third quarter of 2026.
Dermatomyositis is a rare autoimmune disease that causes progressive muscle weakness and distinctive skin rashes. It has historically been managed with systemic corticosteroids and broad immunosuppressive agents, treatments that carry significant long-term side effects and often fail to control both muscle and skin manifestations simultaneously. No targeted therapy has ever been approved for the condition.
What We Know
The VALOR trial enrolled 241 patients across 90 sites globally in a double-blind, placebo-controlled design. Participants were randomized 1:1:1 to receive once-daily oral brepocitinib at 30 mg, brepocitinib at 15 mg, or placebo for 52 weeks, with standard therapies continued and corticosteroids tapered, as published in the NEJM. It is the longest and largest interventional dermatomyositis trial ever conducted.
On the primary endpoint, the 30 mg dose achieved a 15.3-point greater improvement in Total Improvement Score (TIS) at Week 52 compared to placebo (P<0.001), according to Priovant. The 15 mg dose did not reach statistical significance. Treatment effects were evident as early as Week 4 and were sustained through the full 52-week study period.
All nine key secondary endpoints showed statistically significant and clinically meaningful improvements with the 30 mg dose, spanning measures of global disease activity, muscle strength, skin disease severity, physical function, and corticosteroid reduction, as reported by Health Technology Net. Over two-thirds of patients on the 30 mg dose achieved TIS40, which represents twice the minimum clinically important difference.
The steroid-sparing results are particularly notable for a disease where long-term corticosteroid dependence has been the norm. Nearly twice as many patients in the brepocitinib 30 mg group reduced background corticosteroids compared to placebo, and more than half achieved meaningful clinical improvement while reducing their systemic corticosteroid dose to 2.5 mg per day or less, according to the Priovant press release.
Brepocitinib works by selectively inhibiting TYK2 and JAK1, blocking cytokine signaling pathways implicated in dermatomyositis, including type I and type II interferons, IL-6, IL-12, and IL-23. Dr. Ruth Ann Vleugels, chair of dermatology at Harvard Medical School, described the findings as moving the field “beyond the historical paradigm of suboptimal disease control and reliance on systemic corticosteroids toward a patient-centric model focused on rapid, sustained, steroid-sparing efficacy,” according to the press release.
On the safety front, serious infections increased with brepocitinib 30 mg compared to placebo but resolved with medical management, and treatment was completed in most cases. Malignancies, cardiovascular events, and thromboembolic events occurred more frequently in the placebo group. Adverse events leading to treatment discontinuation were also more common with placebo, as reported by Health Technology Net. The overall safety database includes over 2,000 patients and has a profile described as similar to approved JAK and TYK2 inhibitors.
Priovant Therapeutics, a subsidiary of Roivant Sciences, developed brepocitinib. Roivant’s stock has surged approximately 155 percent over the past year, reaching a market capitalization near $19 billion, with multiple analysts raising price targets following the trial results, according to Investing.com.
What We Don’t Know
The trial tested only two doses against placebo. Whether intermediate or higher dosing regimens could improve the benefit-risk profile remains unexplored. The 15 mg dose failed to reach significance on the primary endpoint, leaving a narrow therapeutic window around 30 mg.
Long-term safety beyond 52 weeks has not been established. The increased rate of serious infections with the 30 mg dose, while manageable within the trial, raises questions about chronic use in a patient population that may already be immunocompromised by their disease and background therapies.
Priovant has not disclosed detailed pricing or reimbursement strategy. JAK inhibitors for other autoimmune conditions such as rheumatoid arthritis typically carry annual list prices exceeding $60,000, and access challenges in rare disease populations could limit real-world uptake regardless of clinical efficacy.
Whether brepocitinib will be effective in other forms of myositis beyond dermatomyositis, such as polymyositis or antisynthetase syndrome, remains to be determined through future studies.
Analysis
The VALOR results represent a genuine inflection point for dermatomyositis treatment. For decades, clinicians have managed the disease with blunt immunosuppressive tools, accepting incomplete disease control and corticosteroid toxicity as inevitable trade-offs. A targeted oral therapy that controls both muscle and skin manifestations while enabling steroid tapering addresses the core unmet need in the field.
The publication in the NEJM and the FDA’s Priority Review designation signal that regulatory approval could come as soon as September 2026, potentially making brepocitinib the first therapy ever approved specifically for dermatomyositis. For patients with this rare disease, that timeline represents a meaningful shift from decades of off-label management to a treatment designed and validated for their condition.