Black Diamond Therapeutics, Inc. (BDTX) made a promising announcement on Monday, revealing initial Phase 2 data for their drug BDTX-1535. This data showed encouraging clinical responses and a significant duration of effect in patients diagnosed with relapsed or refractory epidermal growth factor receptor (EGFR)-mutant (EGFRm) non-small cell lung cancer (NSCLC). This is especially significant as patients often develop resistance to the currently available standard treatment, osimertinib (marketed by AstraZeneca Plc as Tagrisso), due to the emergence of on-target resistance EGFR mutations.
The preliminary Phase 2 data, which involved 27 patients receiving 200 mg of BDTX-1535 with a data cutoff on August 17, 2024, demonstrated a positive outlook. Out of 22 response-evaluable patients who met protocol eligibility criteria, the preliminary objective response rate (ORR) was a notable 36%. Notably, 19 of these 22 patients exhibited known osimertinib resistance mutations. Among these 19 patients, 8 experienced a response (42%), with 5 achieving a confirmed partial response (PR), including one patient who progressed from a PR to an unconfirmed complete response (CR) at 8 months. This patient is awaiting a confirmatory scan. Additionally, 3 patients showed an unconfirmed PR at their first scan and are also awaiting confirmatory scans. A further 9 patients demonstrated stable disease.
The durability of the responses observed was also encouraging, with a duration of response (DOR) of approximately 8 months or more for the first three patients who experienced a PR. Notably, 14 out of the 19 patients continue to receive treatment. The mean follow-up time for the study is currently 4.7 months. The majority of adverse events were mild or moderate, and no new safety signals were observed during the trial.
Based on the positive data, Black Diamond Therapeutics has selected a daily dose of 200 mg for pivotal clinical development. The company continues to enroll patients in the second and third-line cohorts, as well as in the first-line setting for patients with non-classical EGFR mutations. Black Diamond expects to release initial results from the first-line cohort in Q1 2025. They will also outline potential registrational paths in the recurrent setting based on feedback from the FDA.
As a result of this positive news, BDTX stock saw an increase of 2.21%, reaching $4.86 at the last check on Monday.
