FDA Approves Remibrutinib for Adults With Chronic Spontaneous Urticaria

FDA approves remibrutinib (Rhapsido) for adults with chronic spontaneous urticaria (CSU) who remain symptomatic despite H1 antihistamine treatment. The approval is for an oral treatment that is taken twice daily and does not require lab monitoring or injections.¹

This is the first Bruton tyrosine kinase inhibitor FDA approved for chronic spontaneous urticaria. | Image Credit: Tanapat Lek,jew - stock.adobe.com

“CSU is a serious disease that can cause debilitating symptoms and unpredictable flares. It’s difficult to diagnose and manage,” Mark Lebwohl, MD, dean for clinical therapeutics at the Icahn School of Medicine at Mount Sinai, said in a news release.¹ “Remibrutinib represents a new way of treating CSU. By blocking the activity of BTK, remibrutinib stops a key pathway of the immune response in CSU. This is an exciting new option that has the potential to help a broad range of patients get fast relief.”

Urticaria, also known as hives, can often be triggered by many situations or substances, according to the American College of Allergy, Asthma and Immunology. For CSU, cases last more than 6 weeks and can last months or up to 5 years. It affects approximately 1.4% of the population and is twice as common in women compared with men. Some cases are associated with autoimmune disorders, and some can indicate thyroid disease or other hormonal issues. However, with most cases, no true etiology is found. Patients are typically treated with medication that blocks the effect of histamine.²

The approval was based on the phase 3 REMIX-1 (NCT05030311) and REMIX-2 (NCT05032157) trials, which evaluated the drug for patients who remained symptomatic on second-generation H1 antihistamines. In REMIX-1, investigators aimed to determine the efficacy, safety, and tolerability of remibrutinib 25 mg twice daily. There were 4 periods, including a screening period of up to 4 weeks, a double-blind placebo-controlled treatment of 24 weeks, an open-label period of 28 weeks, and a treatment-free follow-up period of 4 weeks. REMIX-2 was a replica of REMIX-1.^3,4

The primary outcomes included change from baseline in weekly Urticaria Score (UAS7) at week 12, change from baseline in weekly Itch Severity Score at week 12, and change from baseline in weekly Hives Severity Score at week 12. Secondary end points included number of patients who achieved disease activity control, number of patients who achieved complete absence of hives and itch, number of patients with early onset disease control, and number of individuals with adverse events (AEs).^3,4

There were a total of 470 patients in REMIX-1 and 455 in REMIX-2 who were assigned to remibrutinib (313 and 300 patients, respectively) or the placebo (157 and 155, respectively). Investigators found that remibrutinib decreased UAS8 at week 12 compared with the placebo group, and it was sustained through week 24. At week 12, they reported that 49.8% and 46.8% of patients receiving remibrutinib had a UAS7 of 6 or lower compared with 24.8% and 19.6% on the placebo, respectively. The rates of AEs were similar; however, a higher percentage of patients receiving remibrutinib experienced petechiae.⁵

The approval of remibrutinib is an important development in CSU care. It quickly reduces symptoms, offering patients control of the hives and itching that they experience on a daily basis,” Giselle Mosnaim, MD, MS, an allergist and immunologist from Endeavor Health, said in the news release.¹ “This is significant because it expands beyond existing injectable treatments and gives patients an oral option that can easily be incorporated into their daily lives.”

READ MORE: Allergy Resource Center

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REFERENCES

1. Novartis receives FDA approval for Rhapsido (remibrutinib), the only oral, targeted BTKi treatment for chronic spontaneous urticaria (CSU). News release. Novartis. September 30, 2025. Accessed October 1, 2025. https://www.novartis.com/news/media-releases/novartis-receives-fda-approval-rhapsido-remibrutinib-only-oral-targeted-btki-treatment-chronic-spontaneous-urticaria-csu

2. American College of Allergy, Asthma and Immunology. Chronic spontaneous/idiopathic urticaria (chronic hives). Accessed October 1, 2025. https://acaai.org/allergies/allergic-conditions/skin-allergy/chronic-hives/

3. A phase 3 study of efficacy and safety of remibrutinib in the treatment of CSU in adults inadequately controlled by HI antihistamines (REMIX-1). ClinicalTrials.gov identifications: NCT05030311. Updated April 8, 2025. Accessed October 1, 2025. https://clinicaltrials.gov/study/NCT05030311?term=NCT05030311&rank=1

4. A phase 3 study of efficacy and safety of remibrutinib in the treatment of CSU in adults inadequately controlled by HI antihistamines (REMIX-2). ClinicalTrials.gov identifications: NCT05032157. Updated April 8, 2025. Accessed October 1, 2025. https://clinicaltrials.gov/study/NCT05032157?term=NCT05032157&rank=1

5. Metz M, Giménez-Arnau A, Hide M, et al. Remibrutinib in Chronic Spontaneous Urticaria. N Engl J Med. 2025;392(10):984-994. doi:10.1056/NEJMoa2408792