The FDA has approved the oral drug remibrutinib for the treatment of chronic spontaneous urticaria in adults who continue to be symptomatic despite H1 antihistamine treatment, according to a press release from the manufacturer, Novartis.

Remibrutinib (Rhapsido) is the first FDA-approved Bruton tyrosine kinase (BTK) inhibitor for chronic spontaneous urticaria (CSU), according to the press release. This is also the first approved indication for this agent, which works by selectively targeting BTK to block the release of histamines and mitigate inflammation. It is administered orally twice a day and does not require lab monitoring, according to the company.

Remibrutinib is being investigated as a treatment for other immune-related conditions including chronic inducible urticaria, food allergies, and hidradenitis suppurativa.

CSU affects approximately 1.7 million individuals in the US, but more than half of patients experience symptoms despite treatment with H1 antihistamines, according to the press release.

Approval was based on data from the REMIX-1 and REMIX-2 studies, phase 3 randomized trials of adults with CSU who remained symptomatic despite second-generation H1 antihistamine treatment, which found that those treated with 25 mg of remibrutinib twice daily showed significantly greater improvements in CSU symptoms than those on placebo after 12 weeks. Improvement was based on changes in the weekly urticaria activity score (UAS7), which is designed to assess urticaria symptoms on a scale of 0-42.

Significantly more patients in the remibrutinib group met the primary endpoint of well-controlled disease (UAS7 score of ≤ 6) at 12 weeks, with some meeting this endpoint after 2 weeks. In addition, approximately one third of the patients in the remibrutinib groups experienced complete absence of hives and itch (defined as a UAS7 score of 0) at 12 weeks, according to Novartis.

The most common adverse events associated with remibrutinib included nasal congestion, sore throat, nasopharyngitis, bleeding, headache, nausea, and abdominal pain, according to the press release.

Novartis has filed regulatory submissions for remibrutinib as a treatment for CSU in the EU, Japan, and China.

The study was supported by Novartis.