---
schema_version: "secwatch.filing_event.v1"
accession: "0001193125-23-292084"
form_type: "8-K"
ticker: "COGT"
cik: "0001622229"
company_name: "Cogent Biosciences, Inc."
filed_at: "2023-12-11T23:59:59+00:00"
generated_at: "2026-06-07T14:54:41.442165+00:00"
event_type: "other_material"
sentiment: "positive"
materiality_score: 0.75
calibrated_materiality_score: 0.75
confidence: "high"
source: SEC EDGAR
---

# Cogent reports positive Phase 2 bezuclastinib data in systemic mastocytosis at ASH 2023

## Summary
- SUMMIT Part 1a: 100% of bezuclastinib patients achieved ≥50% reduction in serum tryptase vs 0% on placebo; 100% achieved ≥50% reduction in KIT D816V VAF.
- APEX Part 1: 52% ORR per mIWG-MRT-ECNM criteria (56% in TKI-naïve); 75% PPR ORR (86% in TKI-naïve).
- Safety: no related cognitive impairment or bleeding events; most AEs low grade and reversible.
- SUMMIT Part 2 (registration-directed) to start H1 2024; APEX Part 2 (~65 patients) enrollment on track for end of 2024.
- 100% of bezuclastinib patients in SUMMIT with measurable baseline mast cell aggregates achieved ≥50% reduction in bone marrow mast cell burden vs 14% placebo.

## SEC filing metadata
- accession: 0001193125-23-292084
- form_type: 8-K
- ticker: COGT
- cik: 0001622229
- company_name: Cogent Biosciences, Inc.
- filed_at: 2023-12-11T23:59:59+00:00
- event_type: other_material
- sentiment: positive
- materiality_score: 0.75
- calibrated_materiality_score: 0.75
- confidence: high
- sec_items: 8.01
- EDGAR index: https://www.sec.gov/Archives/edgar/data/1622229/000119312523292084/0001193125-23-292084-index.htm
- EDGAR primary document: https://www.sec.gov/Archives/edgar/data/1622229/000119312523292084/d844329d8k.htm

## Machine-readable alternates
- HTML: https://secwatch.observer/filing/0001193125-23-292084
- JSON: https://secwatch.observer/filing/0001193125-23-292084.json
- Plain text: https://secwatch.observer/filing/0001193125-23-292084.txt

This AI-assisted summary is a reading aid. Review the linked SEC EDGAR filing before relying on any specific claim.