Novartis announced that FDA approved Rhapsido (remibrutinib), an orally administered treatment for Chronic Spontaneous Urticaria (CSU) targeting Bruton’s tyrosine kinase inhibitor (BTKi). Rhapsido was approved for adults diagnosed with CSU who remain symptomatic despite receiving H1 antihistamine treatment and is the first FDA-approved for BTKi in patients with CSU.¹

“This approval of Rhapsido as the first and only BTK inhibitor in CSU is an important milestone in our journey to reshape care for overlooked immune-related conditions and offer more patients the potential to find fast relief,” said Victor Bultó, president, US, Novartis. “Building on our legacy in advancing the treatment of allergic, dermatologic, and rheumatologic conditions, we are deeply committed to further investing in innovative, patient-focused therapies across immunology.”

FDA’s approval was supported through clinical data collected during the REMIX trials

FDA’s approval of Rhapsido in CSU was based on results collected from both the Phase III REMIX-1 and REMIX-2 clinical trials in patients who remained symptomatic on second-generation H1 antihistamines.¹ During these trials Rhapsido demonstrated superiority in change from baseline compared to placebo in itch, hives, and weekly urticaria activity by week 12. Results of the trials showed an increased amount of patients treated with Rhapsido compared to placebo achieved well-controlled disease as early as Week 2 and at Week 12, with around 33% of patients achieving complete absence of itch and hives at Week 12.¹ Rhapsido demonstrated a safety profile requiring no lab monitoring, with the most common adverse events being nasal congestion, sore throat, runny nose (nasopharyngitis), bleeding, headache, nausea, and abdominal pain.¹ Novartis additionally completed regulatory submissions for Rhapsido for the treatment of CSU in the European Union, Japan, and China, with China granting priority review. ¹

What is Chronic Spontaneous Urticaria?

CSU is a mast cell-driven condition believed to be a result of immune dysregulation. Those diagnosed with CSU may experience immune system activation through allergic or autoimmunepathways, causing certain immune cells—mast cells and basophils—to activate the BTK protein.¹ Despite the disease not being fully understood, it is believed that once activated, BTK leads to the release of histamine and other proinflammatory mediators that may cause the red, swollen, and itchy hives commonly seen in CSU.¹

Symptoms of CSU are unpredictable and can reoccur for six weeks or more without an identified cause, with diagnosis taking up to 24 months. ¹ CSU patients report that symptoms negatively impact sleep, work, and mental health, and turn to Antihistamines as the first-line treatment, yet nearly 50% of patients still report symptoms.¹ Injectable treatments exist for those who don't respond to antihistamines, yet fewer than 20% of eligible patients receive them.

“CSU is a serious disease that can cause debilitating symptoms and unpredictable flares. It’s difficult to diagnose and manage,” said Mark Lebwohl, MD, dean for clinical therapeutics at the Icahn School of Medicine at Mount Sinai, and member of the steering committee for the remibrutinib REMIX Phase III clinical trial program. Lebwohl continued, saying, “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.”

Sources

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