Efficacy and Safety of Befotertinib (D-0316) in Patients With EGFR T790M-Mutated NSCLC That Had Progressed After Prior EGFR Tyrosine Kinase Inhibitor Therapy: A Phase 2, Multicenter, Single-Arm, Open-Label Study

Befotertinib (D-0316) is a novel, third-generation EGFR tyrosine kinase inhibitor (TKI). This study evaluated befotertinib in patients with locally advanced or metastatic NSCLC who developed an EGFR T790M mutation after progression on first- or second-generation EGFR TKI therapy.This was a single-arm, open-label, phase 2 study at 49 hospitals across mainland China. Patients with locally advanced or metastatic NSCLC harboring EGFR T790M mutations with disease progression after prior first- or second-generation EGFR TKI therapy received oral befotertinib of 50 mg (cohort A) or 75 to 100 mg (cohort B) once daily. The primary end point was objective response rate (ORR) assessed by an independent review committee in intention-to-treat population. This trial is registered with ClinicalTrials.gov, number NCT03861156.A total of 176 patients and 290 patients were included in cohorts A (50 mg) and B (75-100 mg), respectively. At data cutoff (August 15, 2021), independent review committee-assessed ORR was 67.6% (95% confidence interval [CI]: 61.9%-72.9%) in cohort B. The investigator-assessed ORR was 54.0% (95% CI: 46.3%-61.5%) in cohort A and 65.9% (95% CI: 60.1%-71.3%) in cohort B. The median investigator-assessed progression-free survival was 11.0 (95% CI: 9.6-12.5) months in cohort A and 12.5 (95% CI: 11.1-13.8) months in cohort B. The median independent review committee-assessed progression-free survival in cohort B was 16.6 (95% CI: 15.0-not evaluable [NE]) months. The intracranial ORR was 26.7% (95% CI: 7.8%-55.1%) in cohort A by investigator assessment, while 57.1% (95% CI: 34.0%-78.2%) and 55.9% (95% CI: 37.9%-72.8%) in cohort B by investigator and independent review committee assessment, respectively. The median investigator-assessed intracranial progression-free survival was 16.5 (95% CI: 8.6-NE) months in cohort A, while the median intracranial progression-free survival was not evaluable in cohort B due to immature data regardless of investigator or independent review committee assessment. and NE (95% CI: 13.8-NE) in cohort B. The overall survival was immature. Grade 3 or higher treatment-related adverse events and treatment-related serious adverse events occurred in 20.5% and 11.4% of patients in cohort A and in 29.3% and 10.0% of patients in cohort B, respectively.Befotertinib of 75 to 100 mg has satisfying efficacy and manageable toxicity in patients with locally advanced or metastatic NSCLC harboring T790M mutation with resistance to first- or second-generation EGFR TKIs. A phase 3 randomized trial is underway (NCT04206072).