Afatinib plus bevacizumab combination after osimertinib resistance in advanced EGFR-mutant non-small cell lung cancer: Phase II ABCD-study

Highlights•Osimertinib (OSI) resistant mechanism is diverse.•We investigated the afatinib (AFA) plus bevacizumab (BEV) efficacy after OSI.•Some cases suggested the sensitivity to uncommon EGFR and C797S mutations.•T790M, BRAF, KRAS, and PI3K mutations showed negative predictive impacts.•Selected cases could obtain clinical benefit from AFA + BEV after OSI failure.AbstractIntroductionMany clinical studies showed a synergy of epidermal growth factor receptor (EGFR)-tyrosine kinase inhibitors (TKIs) and vascular endothelial growth factor inhibitors. We hypothesized afatinib plus bevacizumab exerts clinical potency after developing various osimertinib resistant mechanisms.MethodsEGFR-mutant non-small cell lung cancer patients were enrolled after osimertinib resistance. Afatinib at 30–40 mg/day and bevacizumab at 15 mg/kg tri-weekly were administered until progression. Plasma/histologic rebiopsied samples after osimertinib failure were analyzed to examine resistant mechanisms: gene alterations/copy-number gain using cancer personalized profiling by deep sequencing.ResultsBetween January 2018 and October 2020, 28 patients were enrolled. Response and disease control rates were 17.9 % and 78.6 %, respectively. Median duration of response was 9.0 (range, 4.2–22.3) months. Median progression-free and overall survivals were 2.7 and 9.3 months, respectively. Twenty-eight (100 %) plasma and/or 21 (75 %) histologic rebiopsies identified: 17 (61 %) TP53; 15 (54 %) T790M; 9 (32 %) uncommon EGFR; 9 (32 %) MET; 6 (21 %) C797S; 3 (11 %) BRAF; 2 (7 %) HER2; 2 (7 %) KRAS; and 2 (7 %) PI3K mutations. One (17 %) of 6 C797S patients showed complete response. Three (33 %) of 9 uncommon EGFR-mutated patients achieved radiographic response. Neither 15 T790M-positive nor 6 EGFR downstream signaling mutations: BRAF; KRAS; or PI3K-positive patients responded, but 5 (38 %) of 13 T790M-negative patients responded. Adverse events ≥ grade 3 and incidence ≥ 5 % were: hypertension (29 %); proteinuria (7 %); and diarrhea (7 %). There were neither treatment-related death nor interstitial lung disease.ConclusionsSelected population could obtain clinical benefit from afatinib plus bevacizumab, based on rebiopsy results after osimertinib resistance