Remibrutinib Promotes Early Symptom Control in Patients With Chronic Spontaneous Urticaria

Remibrutinib (Rhapsido; Novartis), a highly selective oral Bruton tyrosine kinase (BTK) inhibitor, demonstrated early chronic spontaneous urticaria (CSU) symptom control when compared with placebo, according to results published in the Journal of Allergy and Clinical Immunology. The findings, which will be presented at the 2026 American Academy of Allergy, Asthma & Immunology Annual Meeting in Philadelphia, Pennsylvania, also showed that reduction in disease activity was present within the first 12 hours of treatment and was sustained through day 7.¹

Approved by the FDA in September 2025, remibrutinib was the first BTK inhibitor to be approved for the treatment of CSU. It aims to inhibit the release of histamine and other proinflammatory mediators by targeting BTK, offering a unique approach to CSU management. It is a pill taken twice per day and does not require injections or lab monitoring, making it a more accessible, manageable option for patients.²

CSU is a mast cell–driven condition believed to be caused by immune dysregulation. In people with CSU, the immune system can become activated through allergic (IgE) or autoimmune (IgG) pathways, which then causes certain mast cells and basophils to activate the BTK protein.

Symptoms are unpredictable and can recur for 6 weeks or more without an identified cause. Patients often report that their symptoms negatively impact their sleep, work, and mental health.² For these reasons, effective and fast symptom control is a key goal. This study, which details pooled findings from the phase 3 REMIX-1 (NCT05030311) and REMIX-2 (NCT05032157) clinical trials, demonstrates the efficacy, safety, and tolerability of remibrutinib in adult patients with CSU who are inadequately controlled by H₁ antihistamines. These identical trials randomly assigned patients to receive either 25 mg of remibrutinib (REMIX-1: n = 313; REMIX-2: 300) or placebo (REMIX-1: n = 157; REMIX-2: 155), administered orally twice per day.^1,3,4

The primary end points for both trials are change from baseline in Urticaria Score (UAS7) at week 12, Weekly Itch Severity Score, and Weekly Hives Severity Score, and secondary end points include the number of patients who achieved disease activity control, who achieved complete absence of hives and itch, with early onset of disease control, cumulative number of weeks with disease activity control, and the number of adverse events (AEs), among others.^1,3,4

The pooled findings indicated that, at baseline, the mean ± SE UAS score was about 4.44 ± 0.05 with remibrutinib and 4.30 ± 0.07 with placebo. From days 1 to 7, remibrutinib demonstrated a greater reduction in disease activity compared with placebo. The respective mean ± SE UAS within 12 hours was 3.96 ± 0.07 and 3.99 ± 0.08, reducing to 3.09 ± 0.07 and 3.92 ± 0.08 on day 2, and then 2.25 ± 0.08 and 3.49 ± 0.10 on day 7.

At baseline, approximately 1.3% of patients treated with remibrutinib were in the lowest UAS band compared with only 0.7% of patients receiving placebo. This increased to approximately 6.5% and 2.4% within 12 hours and 37.0% and 9.7% on day 7.¹

These findings follow 52-week findings published in January 2026, which show remibrutinib treatment resulted in sustained improvements in change from baseline in mean weekly UAS (REMIX-1: –23.22 [95% CI, –24.78 to –21.66]; REMIX-2: -22.98 [95% CI, –24.51 to –21.44]), with similar responses observed in patients who transitioned from placebo to remibrutinib at week 24. These were observed as early as 1 week after transitioning treatments. Exposure-adjusted incidence rates of AEs, serious AEs, and AEs that led to discontinuation with 52-week remibrutinib treatment remained equivalent to those shown in a prior 24-week analysis.⁵

Remibrutinib offers a convenient oral, twice-daily dosing option that does not require routine laboratory monitoring, which may reduce access barriers and provide an alternative for patients who prefer to avoid injectable therapies. Pharmacists should counsel patients on the importance of adherence to twice-daily dosing, set expectations for early symptom improvement, and advise when to contact providers if symptoms persist. Although routine lab monitoring is not required, pharmacists should remain vigilant regarding potential drug–drug interactions and monitor for infection risk, bleeding concerns, or other class-related effects associated with BTK inhibition.

As real-world experience with remibrutinib grows, pharmacists will play a central role in optimizing safe and effective use in patients with CSU.

REFERENCES

1. Windom H, Machado P, Ortmann CE, et al. Remibrutinib provides fast symptom relief within the first week of treatment in chronic spontaneous urticaria, as measured by daily Urticaria Activity Score: pooled REMIX-1/-2 Studies. J Allergy Clin Immunol. 2026;157(suppl 2):AB14. doi:10.1016/j.jaci.2025.12.045

2. 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 February 27, 2026. https://www.novartis.com/us-en/news/media-releases/novartis-receives-fda-approval-rhapsido-remibrutinib-only-oral-targeted-btki-treatment-chronic-spontaneous-urticaria-csu

3. A phase 3 study of efficacy and safety of remibrutinib in the treatment of CSU in adults inadequately controlled by H1 antihistamines (REMIX-1). ClinicalTrials.gov. Updated April 8, 2025. Accessed February 27, 2026. https://clinicaltrials.gov/study/NCT05030311

4. A phase 3 study of efficacy and safety of remibrutinib in the treatment of CSU in adults inadequately controlled by H1 antihistamines (REMIX-2). ClinicalTrials.gov. Updated April 8, 2025. Accessed February 27, 2026. https://clinicaltrials.gov/study/NCT05032157

5. Giménez-Arnau AM, Szalewski R, Hide M, et al. Remibrutinib in chronic spontaneous urticaria: 52-week results from two phase 3 studies. J Allergy Clin Immunol. 2026;157(1):143-154. doi:10.1016/j.jaci.2025.09.028