On April 7, 2024 Black Diamond Therapeutics, Inc. (Nasdaq: BDTX), a clinical-stage oncology company developing MasterKey therapies that target families of oncogenic mutations in patients with cancer, reported real-world evidence of the evolving epidermal growth factor receptor (EGFR) mutation landscape in non-small cell lung cancer (NSCLC), and the potential of BDTX-1535 to address a broader range of mutations compared to existing therapies (Press release, Black Diamond Therapeutics, APR 7, 2024, View Source [SID1234641842]). The results were disclosed in an oral presentation on April 7, 2024, at the 2024 American Association of Cancer Research (AACR) (Free AACR Whitepaper) Annual Meeting held in San Diego, California.

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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 (GuardantINFORM) and Foundation Medicine (FoundationInsights). 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.

"The landscape of EGFR mutations in NSCLC continues to evolve, revealing classical and non-classical driver mutations," said John Heymach, M.D., Ph.D., Chair of Thoracic/Head and Neck Medical Oncology at MD Anderson Cancer Center. "Non-classical mutations fall into categories including kinase domain PACC mutations and ectodomain mutations; therefore, next generation EGFR targeted therapies must effectively cover multiple subgroups of mutations."

"Novel targeted therapies are still needed to continue to improve clinical outcomes for patients with EGFR-mutant lung cancers," added Xiuning Le, M.D., Ph.D., Associate Professor, Thoracic/Head and Neck Medical Oncology at MD Anderson Cancer Center. "To extend survival for our patients, newer drugs need to have good mutational coverage, good tolerability, and good brain penetrance."

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.

"BDTX-1535 was designed to address a broad spectrum of more than 50 non-classical oncogenic EGFR mutations, as well as the C797S resistance mutation," said Elizabeth Buck, Ph.D., Chief Scientific Officer and co-founder of Black Diamond Therapeutics. "We believe that the potency of BDTX-1535 against the full spectrum of classical, non-classical, and C797S mutations positions the compound as the first and best-in-class fourth-generation EGFR inhibitor potentially offering NSCLC patients a well-tolerated, brain-penetrant, oral therapy across various lines of treatment."

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 (1L) setting (for those expressing EGFR non-classical mutations) and in second- and third-line (2L/3L) settings following prior treatment with an EGFR inhibitor. Initial results from 2L/3L patients are anticipated in the third quarter of 2024.

About BDTX-1535
BDTX-1535 is an oral, brain-penetrant MasterKey inhibitor of oncogenic epidermal growth factor receptor (EGFR) mutations in non-small cell lung cancer (NSCLC), including classical driver mutations, non-classical driver mutations, and the acquired resistance C797S mutation. BDTX-1535 is a fourth-generation tyrosine kinase inhibitor (TKI) that potently inhibits, based on preclinical data, more than 50 oncogenic EGFR mutations expressed across a diverse group of patients with NSCLC in multiple lines of therapy. Based on preclinical data, BDTX-1535 also inhibits EGFR extracellular domain mutations and alterations commonly expressed in glioblastoma (GBM) and avoids paradoxical activation observed with earlier generation reversible TKIs. A "window of opportunity" trial of BDTX-1535 in patients with GBM is ongoing (NCT06072586) and a Phase 2 trial is ongoing in patients with NSCLC (NCT05256290).