The oral treatment was approved for use on those who continue to experience symptoms despite receiving H1 antihistamine therapy.
Rhapsido is administered in pill form twice daily and does not necessitate injections or laboratory monitoring. This medication is the first Bruton’s tyrosine kinase inhibitor (BTKi) approved by the FDA for CSU. Rhapsido works by inhibiting the release of histamine and other pro-inflammatory mediators through the targeting of BTK.
FDA approved Rhapsido for use in CSU after assessing the results of the Phase III REMIX-1 (NCT05030311) and REMIX-2 (NCT05032157) clinical trials. These trials involved patients who continued to experience symptoms despite treatment with second-generation H1 antihistamines.
REMIX Phase III clinical trial programme steering committee member Mark Lebwohl said: “CSU is a serious disease that can cause debilitating symptoms and unpredictable flares. It’s difficult to diagnose and manage.
“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.”
CSU is a condition driven by mast cells, believed to result from immune dysregulation. In individuals with CSU, the immune system may become activated via allergic or autoimmune pathways, prompting mast cells and basophils to activate the Bruton’s tyrosine kinase (BTK) protein.
Once activated, BTK triggers the release of histamine and other pro-inflammatory mediators, which can lead to the development of red, swollen, and itchy hives.
CSU symptoms are unpredictable and may recur for six weeks or more without a known cause. The diagnostic process can take as long as 24 months. Antihistamines are the primary treatment option; however, over half of patients continue to experience symptoms despite this therapy.
REMIX trial investigator Giselle Mosnaim said: “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.
“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.”