Presence of few PD-1-expressing tumor-infiltrating immune cells is a potential predictor of improved response to salvage chemotherapy following nivolumab for non-small cell lung cancer: An exploratory case series.

Salvage chemotherapy following nivolumab improved anti-tumor activity regardless of tumor PD-L1 status, but nivolumab following chemotherapy did not. The presence of few PD-1+ tumor-infiltrating immune cells may serve as a potential predictor of response to salvage chemotherapy. Further studies involving a large cohort are needed to clarify how nivolumab re-sensitizes the tumor immune microenvironment to chemotherapy.