NEW YORK – Black Diamond Therapeutics said on Monday that it has dosed the first patient in a Phase I trial of its MasterKey EGFR inhibitor BDTX-1535 for glioblastoma and non-small cell lung cancer patients harboring EGFR mutations.
The Phase I trial is designed to assess the safety, tolerability, and preliminary efficacy of BDTX-1535 as treatment for roughly 90 patients with recurrent glioblastoma or recurrent NSCLC.
Eligible glioblastoma patients must have evidence of tumor EGFR alterations, including amplification, variants, or mutations, as determined by next-generation sequencing, RNA sequencing, fluorescence in situ hybridization, immunohistochemistry, or array CGH.
NSCLC patients must have sensitive EGFR mutations and disease progression following standard of care; if they have uncommon EGFR mutations such as the G719X mutation, they must have progressed following an EGFR inhibitor, and if they have acquired resistance EGFR mutations such as C797S, they need to have progressed following a third-generation EGFR inhibitor in the first-line treatment setting.
Cambridge, Massachusetts-based Black Diamond believes that BDTX-1535 can treat tumors with primary TKI-resistant EGFR mutations as well as those with on-target acquired resistance mutations. The firm said that roughly half of glioblastoma patients have EGFR mutations, making them potential candidates for BDTX-1535 treatment. Intrinsic resistance EGFR mutations such as G719X, S768I, and L861Q, make up 10 to 20 percent of EGFR-mutated NSCLC tumors, the company noted.
Even though currently available targeted treatments have worked well for those patients with the classical Exon19del and L858R EGFR mutations, acquired resistance is common. The firm estimates that there are roughly 60,000 BDTX-1535-eligible glioblastoma patients and 20,000 eligible NSCLC patients in the US, EU, Japan, and China per year.
Black Diamond uses its proprietary Mutation-Allostery-Pharmacology, or MAP, drug discovery platform to home in on oncogenic mutations that promote cancer across tumor types, and to create products targeting these mutations.
The firm expects to provide a clinical update from the BDTX-1535 trial during the second half of 2023.