Central nervous system efficacy of furmonertinib (AST2818) in patients with EGFR T790M mutated non-small cell lung cancer: a pooled analysis from two phase 2 studies

Background Furmonertinib (AST2818) is a brain penetrant pan-epidermal growth factor receptor (EGFR) tyrosine kinase inhibitor (TKI) targeting both EGFR sensitizing mutations and T790M mutation. We report the pooled central nervous system (CNS) efficacy data of furmonertinib in patients with EGFR T790M mutated non-small cell lung cancer (NSCLC) from two phase 2 studies. Methods This was a pooled, post-hoc analysis of two phase 2 studies (NCT03127449 [phase 2a study of furmonertinib], NCT03452592 [phase 2b study of furmonertinib]). In the phase 2a study, patients received furmonertinib 40 mg, 80 mg, 160 mg, or 240 mg orally once daily. In the phase 2b study, all patients received furmonertinib 80 mg orally once daily. CNS efficacy of furmonertinib was analyzed in patients with baseline CNS lesions by an independent review center per Response Evaluation Criteria in Solid Tumors version 1.1. Results A total of 132 patients with baseline CNS metastases were included in this analysis. In 52 patients with measurable CNS lesions, CNS objective response rates were zero (0/1), 65% (22/34), 85% (11/13), and 25% (1/4), and CNS disease control rates were zero (0/1), 97% (33/34), 100% (13/13), and 100% (4/4) in the 40 mg, 80 mg, 160 mg, and 240 mg orally once daily group, respectively. In patients with measurable or non-measurable CNS lesions, median CNS progression-free survival was 2.8 months (95% confidence interval [CI] 1.4–8.3), 11.6 months (95% CI 8.3–13.8), 19.3 months (95% CI 5.5-not available [NA]), and not reached (95% CI 2.8 months-NA) in the 40 mg, 80 mg, 160 mg, and 240 mg orally once daily group, respectively. Conclusions Furmonertinib showed promising CNS efficacy in doses of 80 mg orally once daily or higher in patients with EGFR T790M mutated NSCLC. Trial registration Both studies were registered on ClinicalTrial.gov. The phase 2a study was registered with NCT03127449 on April 25, 2017; The phase 2b study was registered with NCT03452592 on March 2, 2018.