A phase 1/2 study of the highly selective EGFR inhibitor, BLU-701, in patients with EGFR-mutant non–small cell lung cancer (NSCLC).

TPS9142 Background: Although 3rd-generation tyrosine kinase inhibitors (TKIs), such as osimertinib, are highly effective in front-line metastatic EGFR-mutated ( EGFRm) NSCLC, treatment resistance ultimately occurs, including the emergence of the on-target C797X mutation for which there are no approved TKIs. BLU-701 is an investigational, reversible, brain-penetrant, wildtype-sparing oral TKI with nanomolar potency on common activating (exon 19 deletion and L858R) and C797X resistance mutations (Tavera L et al. AACR 2022). BLU-701 has shown promising preclinical data, including antitumor central nervous system (CNS) activity that may improve patient outcomes. Additionally, combining BLU-701 with standard of care therapies may provide enhanced disease control across multiple lines of treatment, including against heterogenous tumors, in patients with EGFRm NSCLC. Methods: HARMONY (NCT05153408) is an ongoing, global phase 1/2, open-label, first-in-human study designed to evaluate the safety, tolerability, pharmacokinetics (PK), pharmacodynamics (PD), and antitumor activity of BLU-701 as a monotherapy or in combination with osimertinib or platinum-based chemotherapy in patients with EGFRm NSCLC. Key inclusion criteria include patients ≥18 years of age with metastatic EGFRm NSCLC; Eastern Cooperative Oncology Group performance status 0–1; and previous treatment with ≥1 EGFR-targeted TKI. Patients in the phase 2 monotherapy part must harbor an EGFR C797X resistance mutation (locally assessed). Key exclusion criteria are tumors harboring EGFR T790M mutations, EGFR exon 20 insertions, or other known driver alterations, including KRAS, BRAF V600E, NTRK1/2/3, HER2, ALK, ROS1, MET, or RET. Phase 1 primary endpoints are maximum tolerated dose, recommended phase 2 dose (RP2D), and safety. The phase 2 primary endpoint is overall response rate (ORR) by RECIST 1.1. Secondary endpoints include ORR (phase 1), duration of response, and PK/PD (phase 1 and phase 2); disease control rate, progression-free survival, overall survival, antitumor CNS activity, and safety (phase 2). The phase 1 dose escalation will adopt a Bayesian optimal interval design. Patients will be enrolled into 3 treatment cohorts: part 1A (n≈40–80; BLU-701), part 1B (n≈35; BLU-701 + osimertinib), and part 1C (n≈18; BLU-701 + carboplatin and pemetrexed). Patients in the phase 2 dose expansion (n≈24) will be treated at the RP2D of BLU-701 as monotherapy. Patients may receive treatment until disease progression, unacceptable toxicity, or other discontinuation criteria are met. Enrollment in this study has started, and sites will be open across North America, Europe, and Asia. Clinical trial information: NCT05153408.