Black Diamond Therapeutics presents preclinical data on BDTX-1535 at AACR

Black Diamond Therapeutics presented real-world evidence of the evolving epidermal growth factor receptor mutation landscape in non-small cell lung cancer, and the potential of BDTX-1535 to address a broader range of mutations compared to existing therapies. The results were disclosed in an oral presentation on April 7 at the 2024 American Association of Cancer Research Annual Meeting held in San Diego, California. The oral presentation, titled “BDTX-1535 – A MasterKey EGFR Inhibitor Targeting Classical, Non-Classical and the C797S Resistance Mutation to Address the Evolved Landscape of EGFR Mutant NSCLC,” evaluated more than 235,000 sequenced cases of NSCLC sourced from Guardant Health and Foundation Medicine. The analyses reveal a broad spectrum of non-classical mutations, as well as an increased prevalence of the acquired resistance mutation, C797S. Over 100 unique non-classical EGFR oncogenic driver mutations were identified in newly diagnosed patients with NSCLC, and these non-classical EGFR mutations were present in 20-30% of patients across all lines of treatment. Preclinical data demonstrated that BDTX-1535 potently inhibits more than 50 clinically relevant, non-classical EGFR mutations (as well as the classical L858R and exon19-del mutations) while sparing wild-type EGFR. The compound also potently inhibits the drug resistance C797S mutation, which emerges following treatment with third-generation EGFR inhibitors, including osimertinib. Real-world data indicate non-classical EGFR mutations can be co-expressed with classical mutation L858R, a setting that has been characterized by shorter duration of response to osimertinib first-line therapy. Preclinical data show that BDTX-1535 potently inhibits these co-expressed non-classical mutations. Phase 1 proof-of-concept data demonstrating durable responses in recurrent NSCLC patients with both non-classical and acquired resistance C797S mutations were presented in October 2023. Black Diamond is currently advancing BDTX-1535 in a Phase 2 trial for patients with EGFRm NSCLC across multiple lines of therapy. Patients are being enrolled both in a first-line setting (for those expressing EGFR non-classical mutations) and in second- and third-line settings following prior treatment with an EGFR inhibitor. Initial results from 2L/3L patients are anticipated in the third quarter of 2024.