Cogent Biosciences (COGT) The 66th American Society of Hematology (ASH) Annual Meeting and Exposition 2024 summary

Key clinical trial and program updates

• SUMMIT part two pivotal study for bezuclastinib in non-advanced systemic mastocytosis fully enrolled six months ahead of schedule with 179 patients; top-line results expected July 2025.

• APEX part one in advanced systemic mastocytosis showed a 52% overall response rate per mIWG and 88% per pure pathologic response, with deep, durable responses and favorable safety.

• Both SUMMIT and PEAK pivotal studies surpassed enrollment targets, reflecting strong investigator and patient interest.

• Cash position of $345.5M as of September 30, 2024, provides runway into late 2026.

• Forward-looking statements include plans for regulatory submissions and market expansion in SM and GIST.

Efficacy and safety findings in advanced systemic mastocytosis (APEX)

• 52% overall response rate per mIWG-MRT-ECNM and 88% per PPR criteria in AdvSM patients.

• Deep reductions in mast cell burden biomarkers: 94% achieved ≥50% reduction in serum tryptase, 100% in bone marrow MC burden, and 93% in KIT D816V VAF.

• Median progression-free survival and duration of response not reached; 82% PFS rate at 24 months.

• Majority of adverse events were low grade and reversible; no intracranial bleeding or cognitive impairment reported.

• 100mg BID dose showed optimal efficacy and safety, with no discontinuations due to adverse events.

Efficacy and safety findings in non-advanced systemic mastocytosis (SUMMIT)

• 76% of patients achieved at least a 50% reduction in symptoms at 24 weeks; 88% achieved at least a 30% reduction.

• 89% had ≥50% decrease in serum tryptase by 4 weeks, sustained through 24 weeks.

• Significant improvements in quality of life, with MC-QoL total score reduced by 49% at 24 weeks.

• Symptom improvement and quality of life scores deepened with longer treatment; 65% mean improvement at 48 weeks.

• Majority of treatment-emergent adverse events were low grade and reversible; no treatment-related bleeding or cognitive impairment.