Induction of natural killer antibody-dependent cell cytotoxicity and of clinical activity of cetuximab plus avelumab in non-small cell lung cancer

Background Antibody-dependent cell-mediated cytotoxicity (ADCC) may mediate antitumour activity of IgG1-isotype monoclonal antibody (mAb), suggesting as potential treatment combination of IgG1-mAbs, anti-epidermal growth factor receptor cetuximab and anti-programmed death-ligand-1 avelumab. Methods We evaluated ADCC induction in lung cancer cells by lactate dehydrogenase (LDH) release assay. Antitumour activity and safety of cetuximab plus avelumab were explored in a single-arm proof-of-concept study in pre-treated non-small cell lung cancer (NSCLC) patients (pt) (Cetuximab-AVElumab-lung, CAVE-Lung). Search for predictive biomarkers of response was done. Results Avelumab plus cetuximab induced ADCC in NSCLC cells in vitro in presence of natural killers (NK) from healthy donors (HD) or NSCLC pt, as effectors. Sixteen relapsed NSCLC pt were treated with avelumab plus cetuximab. Antitumour activity was observed in 6/16 pt, defined by progression free survival (PFS) >= 8 months, with 4 of them still on treatment at data lock time (range, 14-19 months). Of note, 3/6 responders had received as previous line anti-programmed death-1 therapy. In responders, clinical benefit was accompanied by significant increase in LDH release over baseline at the first radiological evaluation (8 weeks) (p=0.01) and by early skin toxicity; while in the 10 non-responders, that had PFS <= 5 months, LDH release tends to reduce. Baseline circulating DNA levels were higher in non-responders compared with responders and HD (p=0.026) and decrease in responders during therapy. Mutations in DNA damage responsive family genes were found in responders. Conclusion Cetuximab and avelumab activates NSCLC pt NK cells. Ex vivo evaluation of ADCC, circulating DNA levels and early skin toxicity may predict response to cetuximab plus avelumab in NSCLC. EUDRACT 2017-004195-58