Cogent's Bezuclastinib Shows Promise in Systemic Mastocytosis, Challenging Blueprint's Ayvakit

Cogent Biosciences has announced positive results from its Phase II SUMMIT trial for bezuclastinib, a tyrosine kinase inhibitor targeting systemic mastocytosis. The data positions the drug as a potential competitor to Blueprint Medicines' Ayvakit, recently acquired by Sanofi in a $9.5 billion deal.

Impressive Efficacy and Safety Profile

Bezuclastinib demonstrated significant symptom reduction in patients with non-advanced systemic mastocytosis. The treatment arm achieved a 24.3-point decrease in total symptom scores compared to 15.4 points in the placebo group, using Cogent's proprietary measurement scale.

The drug also showed promising results in secondary endpoints, with 87.4% of treated patients experiencing a 50% drop in serum tryptase levels, a key biomarker for mastocytosis. No patients in the placebo arm achieved a similar reduction.

Notably, bezuclastinib's safety profile exceeded expectations. Common side effects included changes in hair color (69.5%), altered taste (23.7%), and elevated liver enzymes (22.0%). Analysts at Leerink highlighted the drug's improved safety profile compared to Ayvakit, attributing it to "higher selectivity and lack of brain penetrance."

Market Implications and Industry Response

The positive results have significant implications for the systemic mastocytosis market. Leerink analysts project peak revenues of approximately $2.5 billion for bezuclastinib. Cogent's stock surged 26% following the announcement, reflecting investor optimism.

Andrew Robbins, Cogent's CEO, expressed enthusiasm about the results, stating, "We have been eagerly awaiting this day. Our team is already at work on our first new drug application for bezuclastinib that we expect to file with the FDA later this year."

Kelly Shi, a Jefferies analyst, described the data as a "home run scenario" for Cogent, noting that the trial enrolled more severe patients compared to Blueprint's tests of Ayvakit.

As the systemic mastocytosis treatment landscape evolves, bezuclastinib's potential approval could offer a new option for patients, particularly those with higher symptom burdens not adequately treated by existing therapies.