BACKGROUND

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.

METHODS

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.

RESULTS

Patients with T790M mutation detected by tissue rebiopsy (n = 22) had significantly better PFS than those by plasma-based biopsy (n = 96) (median PFS: 415 vs 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).

CONCLUSIONS

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.