Novartis Secures FDA Approval for Oral BTK Inhibitor Rhapsido in Chronic Hives Treatment

The U.S. Food and Drug Administration (FDA) has approved Novartis' remibrutinib, to be marketed as Rhapsido, for the treatment of chronic spontaneous urticaria (CSU) in adult patients who remain symptomatic despite H1 antihistamine treatment. This approval marks a significant milestone as Rhapsido becomes the first oral and targeted Bruton's tyrosine kinase (BTK) inhibitor for CSU, offering a new treatment option for the estimated 1.7 million Americans affected by this condition.

A Novel Approach to Chronic Hives Management

Rhapsido represents a paradigm shift in CSU treatment, providing an oral alternative to existing injectable therapies such as Roche's Xolair and Sanofi and Regeneron's recently approved Dupixent. The drug's mechanism of action targets the BTK enzyme, disrupting the signaling cascade responsible for histamine secretion, which causes the characteristic itching and swelling in CSU patients.

Dr. Giselle Mosnaim from the University of Chicago, an investigator in the REMIX clinical trial program, highlighted the significance of this approval, stating, "Rhapsido gives patients an oral option that can easily be incorporated into their daily lives." This convenience factor is expected to improve treatment adherence and accessibility for patients who have not found relief with antihistamines alone.

Clinical Efficacy and Market Positioning

The FDA's decision was based on compelling data from the Phase III REMIX program, published in the New England Journal of Medicine. The trials demonstrated Rhapsido's superiority over placebo in reducing urticaria activity scores, with benefits sustained through 24 weeks of follow-up. Notably, long-term data presented last year showed that almost half of the patients were completely free of itch and hives at the one-year mark.

Victor Bulto, Novartis' U.S. president, explained the drug's market positioning, stating that Rhapsido is intended for use immediately after antihistamines cease to be effective. Novartis estimates the target CSU population in the U.S. to be around 400,000 patients, with only about 20% currently being treated with either Xolair or Dupixent, indicating significant growth potential for Rhapsido.

Competitive Landscape and Future Prospects

The approval of Rhapsido intensifies competition in the immunology space, particularly in the realm of BTK inhibitors. Sanofi recently received FDA approval for its BTK inhibitor Wayrilz in immune thrombocytopenia and has already initiated a Phase III study for chronic hives. Both Novartis and Sanofi are actively exploring additional indications for their respective BTK inhibitors, signaling a broader trend in leveraging this drug class across various immunological disorders.

Novartis is advancing Rhapsido's development in several other indications, including chronic inducible urticaria, multiple sclerosis, hidradenitis suppurativa, and generalized myasthenia gravis. The company anticipates pivotal readouts for some of these indications by 2026. Additionally, promising Phase II results in food allergy have opened up the possibility for Rhapsido to become the first oral allergen-agnostic treatment in this area, potentially addressing a significant unmet need for the estimated 20 million food allergy sufferers in the U.S.

As Novartis prepares for the commercial launch of Rhapsido, with availability expected "in the coming days," the pharmaceutical industry watches closely to see how this novel oral therapy will reshape the landscape of chronic spontaneous urticaria treatment and potentially other immunological disorders.