The U.S. Food and Drug Administration accepted the New Drug Application for bezuclastinib in patients with nonadvanced systemic mastocytosis (SM), according to a press release published recently. A decision is expected by December 30, 2026.
The FDA does not plan to convene an advisory committee at this time. The agency also has not flagged potential issues during its initial review, which may streamline the evaluation process. For patients, this signals that the treatment is moving steadily through regulatory review.
The application is supported by results from the SUMMIT trial, which showed clinically meaningful and statistically significant improvements across both primary and secondary endpoints. Patients experienced reductions in symptoms across all measured domains, an important outcome in a disease that can affect multiple organ systems and quality of life.
“Data from the SUMMIT trial through 48 weeks showcased a clear and continued deepening of symptomatic improvement over time, supporting the potential for sustained clinical benefit with longer duration of therapy,” explained the press release.
Read more about therapies for SM
Data collected through 48 weeks indicated that symptom relief deepened over time, suggesting that longer treatment could provide sustained benefits. The trial also showed improvements in bone mineral density and signs of disease modification, which may indicate that the therapy is addressing underlying disease processes rather than only relieving symptoms.
Bezuclastinib was generally well tolerated in the study, with a safety profile that supports ongoing, long-term use. This is particularly relevant for patients with nonadvanced SM, who often require chronic management of symptoms such as skin reactions, gastrointestinal issues and fatigue.
The drug targets the KIT D816V mutation, a key driver of SM, by inhibiting abnormal mast cell growth. Beyond this indication, the company is also pursuing approvals for other conditions, including gastrointestinal stromal tumors and advanced SM, with additional regulatory submissions planned in 2026.
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