Summary of Foghorn Therapeutics FY Conference Call Company Overview - **Company**: Foghorn Therapeutics (NasdaqGM:FHTX) - **Focus**: Targeting the chromatin regulatory system and the BAF complex, primarily in oncology [2][3] Industry Insights - **Oncology Relevance**: Approximately 50% of cancers have dependencies or mutations related to chromatin regulation, highlighting the importance of this area in cancer biology [2] - **Targeting Challenges**: The similarity between proteins in the BAF complex (e.g., SMARCA2 and SMARCA4) complicates selective targeting due to their 90%-95% similarity [3][4] Key Programs and Developments SMARCA2 Program - **Scientific Rationale**: SMARCA2 is targeted due to its synthetic-lethal relationship with SMARCA4, where loss of SMARCA4 increases dependency on SMARCA2 in cancer cells [6][7] - **Clinical Data**: Patients with SMARCA4 mutations show significantly worse prognosis in non-small cell lung cancer, with response rates dropping from approximately 40% to 20% [7] - **Market Opportunity**: In the U.S., about 22,000 non-small cell lung cancer patients have SMARCA4 mutations, with an estimated 11,000-17,000 potentially having loss of function [8] Clinical Trials - **Current Status**: The SMARCA2 inhibitor FHD-909 is in phase one trials, with ongoing dose escalation and no maximum tolerated dose reached yet [16][17] - **Study Design**: The trial includes various cancer histologies with a focus on non-small cell lung cancer patients with SMARCA4 mutations [15] - **Expected Outcomes**: Anticipation of a go/no-go decision for dose expansion in the first half of 2026 [16] CBP and EP300 Programs - **Mechanism**: CBP and EP300 are sister proteins involved in histone acetylation, with challenges in dual inhibition leading to myelosuppressive effects [21][22] - **Commercial Opportunity**: Targeting CBP could address approximately 20,000-25,000 patients with specific mutations, while EP300 shows potential in hematological malignancies [23][24] ARID1B Program - **Target Validation**: ARID1B is a highly mutated target in cancer, with Foghorn being the only company to develop selective binders for this target [27][28] - **Development Status**: The program is in hit-to-lead stage, with in vivo proof of concept expected in 2026 [29] Additional Insights - **Combination Studies**: The company recognizes the importance of combination therapies in oncology and plans to explore both monotherapy and combination regimens in future studies [18][19] - **Clinical Risks**: Acknowledgment of the risks associated with being first to market, particularly in the context of the SMARCA2 program [9][10] Conclusion Foghorn Therapeutics is positioned in a promising niche within oncology, focusing on challenging targets related to chromatin regulation. The company is advancing several innovative programs, particularly in SMARCA2, CBP, and EP300, with significant market opportunities and ongoing clinical trials that could lead to impactful treatments for cancer patients.

Ongoing FHD-909 (LY4050784) Phase 1 dose escalation trial in SMARCA4 (BRG1)-mutated cancer remains on track with non-small cell lung cancer (NSCLC) as the primary target population Selective CBP degrader entered non-GLP toxicology studies in Q4 2025 with potential in EP300-mutant cancers and ER+ breast cancer; IND-ready in 2026 Robust preclinical anti-tumor activity and favorable tolerability across hematological malignancies differentiate novel, Selective EP300 degrader from dual CBP/EP300 approachesSelec ...