Exhibit 99.1 Foghorn Therapeutics Provides Second Quarter 2025 Financial and Corporate Update FHD-909 (LY4050784) Phase 1 dose escalation trial in SMARCA4 (BRG1) mutated cancers, with non-small cell lung cancer (NSCLC) as the primary target population, is enrolling well and remains on track Preclinical synergistic benefit of FHD-909 in combination with pembrolizumab and KRAS inhibitors reinforces significant potential in NSCLC Selective CBP degrader on track for IND-enabling studies, targeting an IND in 202 ...