A pill recently approved to treat chronic hives may also help protect against peanut allergy, early research suggests.
The Food and Drug Administration approved the drug remibrutinib in September 2025 to treat adults with chronic spontaneous urticaria (CSU) that’s not well-controlled by antihistamines.
Now, researchers are testing whether it can prevent reactions to peanuts and possibly other foods.
The Phase 2 study in peanut allergy involved 59 adult participants. They took remibrutinib pills at either 25 milligrams (mg), 50 mg, or 100 mg, for four weeks.
A fourth group (seven people) received placebo pills. A fifth group in the blinded study took a placebo for three weeks, then one week of remibrutinib.
Success was defined as being able to eat at least 600 mg of peanut protein, or a 1,044 cumulative dose, during a food challenge, without significant allergic symptoms.
Results were dose-dependent, says Dr. Robert Wood, the study’s first author.
At 10 mg for four weeks on the pill, which is known as a Bruton’s tyrosine kinase or BTK inhibitor, about 40 percent could tolerate 600 mg of peanut. At 25 mg, 50 percent could. Then at 100 mg, 87 percent could consume that much. No one in the placebo group could tolerate 600 mg.
“This was a dose-related effect,” says Wood, director of pediatric allergy and immunology at Johns Hopkins Children’s Center. As the dose escalated, “there was clearly a higher success rate.”
All six participants who received a 25 mg dose for just one week also tolerated 600 mg. Wood says the small sample size may explain some of that effect. However, “it suggests this drug has a very rapid onset,” Wood said in an interview with Allergic Living.
“It was a very small sample, but as proof of concept, it’s very exciting,” he added.
BTK Pill and Other Allergens
Wood presented the results at the 2026 American Academy of Allergy, Asthma and Immunology annual meeting in Philadelphia.
Some study participants tolerated even more peanut. About 33 percent receiving the 10 mg dose, 44 percent receiving 25 mg and 80 percent receiving 100 mg could tolerate 1,000 mg. One peanut is 250 to 300 mg, so that’s about three or four peanuts.
At 3,000 mg of peanut, 7 percent on the 10 mg dose, 44 percent on the 25 mg dose, and 47 percent on the 100 mg dose could tolerate that much.
If the drug is eventually approved, it “has the potential to be allergy agnostic,” Wood says, meaning it could be used for any food allergy.
There were no serious adverse events, and the drug was well-tolerated. All participants had their peanut allergy confirmed by a food challenge at the start of the study.
A Phase 3 study in peanut-allergic adults is planned for later in 2026.
Approved for Chronic Hives
Sold by Novartis under the brand name Rhapsido, remibrutinib is a “highly selective” Bruton’s tyrosine kinase inhibitor.
It blocks BTK, a key signaling enzyme in the activation of mast cells and basophils. When these immune cells are activated during IgE-mediated allergic reactions, they release histamine and other inflammatory molecules. These are responsible for symptoms such as itching, hives, swelling and potentially, anaphylaxis.
In the Phase 3 trials that led to the approval for chronic hives, remibrutinib significantly reduce itch and hives by 12 weeks. Some participants saw improvements within one week. After one year, nearly half were symptom-free. Chronic urticaria patients typically take 25 mg, twice daily.
Earlier research using a different BTK inhibitor, acalabrutinib, found the medication provided rapid protection from peanut allergy. In a Phase 2 study in 2023, 10 peanut-allergic adults received four doses of acalabrutinib over two days.
During a subsequent food challenge, seven of the 10 tolerated over 4,000 mg of peanut without reacting. That’s 16 to 20 peanuts. “The onset of action is so rapid, within hours to days,” said Dr. Melanie Dispenza, that study’s author.
In a plenary presentation at the AAAAI meeting, Dr. James Baker noted the promise of BTK inhibitors. “The mast cell may be the most important target we have for trying to treat these patients,” said Baker, director of the University of Michigan Mary H. Weiser Food Allergy Center.
“As we get more and more specific and more and more able to define BTK activity and use inhibitors to block it, I think we have an opportunity to prevent allergic reactions in food-allergic individuals,” Baker says.
Related Reading:
After Stopping Xolair, Kids Could Eat Some Allergenic Foods
Low-Dose Peanut OIT Worked Well in Study
