Increased Response Rates to Salvage Chemotherapy Administered after PD-1/PD-L1 Inhibitors in Patients with Non-Small Cell Lung Cancer.

INTRODUCTION: Although programmed cell death 1 (PD-1)/programmed death ligand 1 (PD-L1) inhibitors have shown some efficacy in treating advanced NSCLC, their benefits are limited to only a subset of patients. Advanced NSCLC is generally treated with a chemotherapy and immunotherapy series. Here we evaluated whether PD-1/PD-L1 inhibitors affect the antitumor effects of salvage chemotherapy administered after immunotherapy (SCAI) in patients with NSCLC.

METHODS: This study included patients with available SCAI response data. We compared the SCAI objective response rates (ORRs) with the ORRs after the last chemotherapy administered before immunotherapy (LCBI).

RESULTS: In total, 73 patients met the inclusion criteria and were included in the analyses. Of these patients, 10 received PD-1/PD-L1 inhibitors as first-line therapy and the remaining 63 had available LCBI response data. Of the 73 patients treated with SCAI, 39 (53.4%) achieved the ORR, whereas the ORR of LCBI was 34.9% (22 of 63) (p = 0.03). We also compared the ORRs of the SCAI and LCBI groups after stratification into platinum doublet therapy versus nonplatinum monotherapy. The ORRs for platinum doublet SCAI and LCBI therapies were 66.7% (16 of 24) and 39.5% (17 of 43), respectively (p = 0.03), whereas for nonplatinum SCAI and LCBI monotherapies they were 46.9% (23 of 49) and 25.0% (5 of 20), respectively (p = 0.09).

CONCLUSIONS: The ORR for SCAI was significantly higher than that for LCBI. These data indicate that anti-PD-1/PD-L1 inhibitors could make tumors more vulnerable to subsequent chemotherapy.