PD-L1 ≥ 50% lung cancer refractory to PD-1 inhibition: the role of salvage chemo-immunotherapy combination.

Novel treatment strategies incorporating PD-1/PD-L1 inhibitors in the first-line setting of advanced non-small-cell lung cancer (NSCLC) provided relevant improvements in survival outcomes. Among NSCLC patients with PD-L1 tumor proportion score ≥50%, identifying the ones to be addressed to pembrolizumab monotherapy or chemo-immunotherapy combinations is a matter of debate, taking into account the risks of overtreatment and toxicity. Here we report the clinical stories of four NSCLC patients with PD-L1 tumor proportion score ≥50% and good performance status, sharing high tumor burden including serosal involvement. After having rapidly progressed on first-line PD-1/PD-L1 inhibitors, they achieved major clinical and radiological response to pembrolizumab-chemotherapy combination. These cases prove the feasibility and effectiveness of salvage chemo-immunotherapy in pembrolizumab-refractory NSCLC patients.