In August 2026, the FDA approved brepocitinib (Lisraya) for adults with dermatomyositis, a rare and debilitating disease in which the immune system attacks muscle and skin.
Brepocitinib is the first medicine in pill form that's approved specifically for this condition. Previously, doctors have used steroids, intravenous immunoglobulin (IVIG) infusions, and medications approved for other autoimmune conditions to treat dermatomyositis. Brepocitinib works in a targeted way by blocking key immune and inflammatory signals known as JAK pathways. It belongs to a growing class of medications called JAK inhibitors, all of which work by blocking various components of this inflammatory pathway.
The FDA approval of this new medication was based on phase 3 clinical trial results reported in The New England Journal of Medicine. The trial included people with dermatomyositis that was resistant to earlier therapies. After 52 weeks of treatment, the results showed significantly more improvement in those who took 30 milligrams of brepocitinib daily along with their standard treatments, compared to those who got a placebo, or fake, pill instead.
"Understanding the [disease] mechanism can really move a field in a big way, and I think brepocitinib is evidence of that," says Julie Paik, MD, co-director of the Johns Hopkins Myositis Center in Baltimore. "It's rooted in touching the patient and understanding what's going on — not just working in the lab."
Learn more about the decade-long research and development process that led to brepocitinib's approval.
Step 1: Drug Discovery and Development
To find promising new medications, researchers have to first understand the condition they aim to treat. That requires detailed study of the underlying biology.
Studies had pinpointed a role for inflammatory messengers called cytokines as drivers in dermatomyositis and its symptoms. Researchers also knew those signals depend on two enzymes: tyrosine kinase 2 (TYK2) and Janus kinase 1 (JAK1). It suggested medicines in the class known as JAK inhibitors might work to treat the disease in a new way.
Meanwhile, other drug development researchers were tinkering in the lab with various JAK inhibitor compounds. In 2012, they landed on one, now called brepocitinib.
Step 2: Studies in the Lab
Unlike other JAK inhibitors, brepocitinib works in two ways instead of one. Studies in the lab showed it binds to TYK2 and JAK1 over other kinases. In human blood cells and samples, the compound could block cytokine signals that cause inflammation. It suggested it might hold promise for treating people with autoimmune conditions, including dermatomyositis.
Step 3: Testing in People
When studies in the lab and in animals look promising, it's time to move on to clinical trials testing a new medicine in people.
Proof-of-concept trial
It turned out there was already evidence a JAK inhibitor might work for dermatomyositis, following approval of the first JAK inhibitor for rheumatoid arthritis (RA) called tofacitinib (Xeljanz) in 2012. When Paik prescribed it for a patient with RA and dermatomyositis, she says that the redness in her skin "melted away."
It inspired her to lead the first proof-of-concept trial using a JAK inhibitor for dermatomyositis. The researchers enrolled 10 people with dermatomyositis that hadn't responded to other medicines. By 12 weeks, all of them showed at least some improvement. The findings suggested a larger randomized and controlled clinical trial of a JAK inhibitor for dermatomyositis was warranted, to see how well it might work in more people. But the focus wasn't on brepocitinib yet.
Phase 1: Is brepocitinib safe?
Altogether, researchers have tested the safety of brepocitinib in 10 phase 1 trials including people with various autoimmune conditions. Phase 1 trials usually include 100 or fewer volunteers and last several months. The goal is to find a dose that's safe. Phase 1 trials also look at how a medication works in the body. They sometimes offer early insight into whether a treatment might work, too.
Phase 2: Is it safe and effective?
Phase 2 studies often enroll hundreds of patients with a condition. They also last up to two years. The goal of a phase 2 study is to look at how a treatment works. These studies also identify potential side effects.
Researchers have conducted eight phase 2 studies testing brepocitinib in all. But none of the phase 2 studies looked at this medicine in dermatomyositis. Instead, phase 2 studies have looked at safety, tolerability, and efficacy of brepocitinib in many other autoimmune conditions, including:
- Plaque psoriasis
- Psoriatic arthritis
- Alopecia areata
- Crohn's disease
- Ulcerative colitis
- Hidradenitis suppurativa
- Systemic lupus erythematosus
- Non-segmental vitiligo
All but one of the phase 2 trials suggested that brepocitinib might work. They also suggested that the medication might work rapidly, within four weeks. While they didn't put it to the test in people with dermatomyositis, similarities in the underlying biology of the diseases suggested it might be a promising JAK inhibitor for dermatomyositis.
Phase 3: Is it safe and effective for more people?
Would it work in people with dermatomyositis, too? Earlier evidence and experience with off-label JAK inhibitors suggested that it would, Paik says. It also made sense given what's known about the underlying causes of dermatomyositis. The strength of earlier evidence enabled researchers to move straight to a phase 3 trial.
"The FDA went for that because there was just so much overwhelming evidence that JAK inhibition is efficacious in DM," Paik says. "It was refreshing to see a company deeply invested in rare diseases decided to run a phase 3 trial so that our patients could get an FDA-approved drug for their disease."
The clinical trial enrolled 241 people with dermatomyositis. They were split into three groups: One got 30 milligrams of brepocitinib daily, another got 15 milligrams, and a third got the placebo pill. At 52 weeks, the group that got the higher-dose medicine showed more improvement than the placebo group.
Improvements with the treatment included reduced:
- Skin disease activity
- Steroid use
- Functional disability
Those improvements also showed up as early as week four.
"The proof-of-concept trial that I led really demonstrated that it worked very quickly, within four weeks, and all of our other oral steroid-sparing agents work within three months," Paik says. "So for a drug to work quickly like that was really remarkable in the proof-of-concept, and then it was affirmed in the large phase 3 trial, which was nice to see."
Is it safe?
Six percent of people in the trial stopped taking the medicine at the higher dose due to side effects. But 11% dropped out of the placebo group. The most common side effects included:
- Respiratory infections
- Headache
- Fatigue
- Urinary tract infections
- Nausea
The medication comes with a black box warning for:
- Serious infections
- Increased mortality
- Cancers
- Serious cardiovascular events or heart problems
- Blood clots
Paik notes that they did not observe any serious cardiovascular events, such as stroke, in the trial. They primarily saw evidence of more infection risk, which is expected when treating an autoimmune disease, she says.
Step 4: Checking by Experts
After a positive phase 3 trial, drug developers submit all the data to the FDA. In the case of brepocitinib, the FDA granted priority review and approved the TYK2-JAK1 inhibitor as the first pill for dermatomyositis in August 2026. It's also the first approved medicine in its class.
Step 5: Watching Over Time
Once a new medication gets approved, it enters phase 4 trials during what's known as post-market safety monitoring.
"We have plans to follow our own patients and see how they do, but on the national level, it's required by the FDA that they will capture this data," Paik says.
Continued study will catch any other serious side effects as more people take the medication for longer periods of time. Doctors will also learn more about how the medication works for more people, including those who may not have been eligible to enroll in the trial.
The Bottom Line
Brepocitinib is approved by the FDA for adults with dermatomyositis and is available to those who wish to try it. The medication works quickly, with infection risk as the most common side effect. But people with certain other health problems may need to proceed with caution. The approval shows how treatment advances can come from many years of careful study and care, both in the lab and the clinic.
