When compared to plasma‐based detection, osimertinib‐treated non‐small cell lung cancer (NSCLC) with tissue rebiopsy‐confirmed acquired T790M mutation is associated with better survival

Abstract

Osimertinib has been approved by the Food and Drug Administration (FDA) of the United States (US) for the treatment of progressive non-small cell lung cancer (NSCLC) that has acquired T790M mutation during treatment with first-line epidermal growth factor receptor-tyrosine kinase inhibitors (EGFR-TKI). We compared the progression-free survival (PFS) of patients whose T790M mutation was identified by tissue rebiopsy with those by plasma-based biopsy. This is a retrospective single-center cohort study conducted in Queen Mary Hospital, Hong Kong S.A.R. that included 118 Chinese patients with advanced NSCLC who had disease progression after treatment with a first-line EGFR tyrosine kinase inhibitor and received osimertinib upon detection of T790M mutation, either by tissue rebiopsy or plasma-based biopsy (by identification of circulating tumor DNA in the peripheral circulation). The primary endpoint is PFS. Patients with T790M mutation detected by tissue rebiopsy (n=22) had significantly better PFS than those by plasma-based biopsy (n=96) (median PFS: 415vs 224 days, P=.018) Hazard ratio for PFS, in favor of the tissue rebiopsy group, was 0.496 (95% confidence interval [CI]: 0.277-0.889). For patients who have NSCLC that progressed after first-line EGFR-TKI, rebiopsy by peripheral blood liquid biopsy and tissue rebiopsy for T790M mutation may have prognostic implication in terms of differences in PFS.