Bezuclastimib significantly reduced symptoms in nonadvanced SM: company

Bezuclastinib’s safety and efficacy are currently being tested.

Bezuclastimib appears to significantly alleviate symptoms in patients with nonadvanced systemic mastocytosis (SM), Cogent Biosciences Inc. announced recently.

Bezuclastinib’s safety and efficacy are currently being tested in SUMMIT, the registration-directed, randomized, double-blind, placebo-controlled, global, multicenter clinical trial. The study enrolled more than 170 patients with nonadvanced SM. 

Systemic mastocytosis (SM) is a rare hematological disease characterized by mast cells that are overactive and accumulate in different parts of the body such as the bone marrow, liver, spleen, gastrointestinal tract and lymph nodes.

“The SUMMIT data reported today are encouraging to thousands of NonAdvSM patients around the world who are waiting for a novel treatment that can rapidly and meaningfully improve a wide variety of symptoms that impact their daily lives,” said Andrew Robbins, Cogent’s president and CEO, in a statement.

Read more about SM therapies

Preliminary results after 24  weeks showed that patients receiving 100mg of bezuclastinib had better results in the Mastocytosis Symptom Severity Daily Diary (MS2D2) and the Mastocytosis Quality-of-Life (MC-QoL) scales than patients receiving placebo, the company said. Patients taking bezuclastinib reported a 56% improvement in the total symptoms score (TSS), and 31% of patients discontinued best supportive care medications. 

Laboratory workups revealed that patients in the bezuclastinib group had a significant decrease in serum tryptase levels, with close to 90% of patients experiencing a 50% decrease. 

The majority of adverse effects associated with bezuclastinib were mild or moderate, with hair discoloration and transitory liver enzyme elevations being the most frequent, the company said.

Bezuclastinib is an experimental drug that acts as a selective tyrosine kinase inhibitor. The drug is currently being tested in clinical trials for its potential therapeutic uses in SM and gastrointestinal stromal tumors (GIST). 

By selectively inhibiting the KIT D816V mutation, bezuclastinib can prevent mast cell proliferation and survival, decreasing the symptom burden in patients with SM, the company said.