Neoadjuvant PD-1 inhibitor combines with chemotherapy versus neoadjuvant chemotherapy in resectable squamous cell carcinoma of the lung

Background A single-agent of anti programmed cell death 1/programmed cell death ligand 1 (anti-PD-1/PD-L1) therapy has been explored for resectable lung cancer before surgery. However, the effectiveness and safety of neoadjuvant programmed cell death 1 (PD-1) blockade combined with chemotherapy have not been published. Methods Twenty-one consecutive patients with potentially resectable squamous cell carcinoma of the lung who received neoadjuvant therapy followed by surgery in Beijing Cancer Hospital were included in this study. Eight patients received two cycles of neoadjuvant platinum-based doublet chemotherapy combined with anti-programmed cell death 1 (anti-PD-1) therapy, while 13 patients received two cycles of neoadjuvant platinum-based doublet chemotherapy only. Chest computed tomography was repeated before neoadjuvant treatment and surgery. Adverse events were monitored. The major pathological response (MPR) rate was determined after surgery. Selected specimens were sent for immunohistochemical and multiplex immunofluorescence analyses, and T-cell receptor DNA sequencing. Results Compared with neoadjuvant chemotherapy alone, the combination of PD-1 blockade and chemotherapy increased the pathological complete response rate (37.5% vs. 7.69%) and MPR rate (50% vs. 38.46%). The pathological and radiological evaluations are not consistent. No unknown adverse effects were reported for all the patients. More tumor infiltrating lymphocytes were observed in patients who received PD-1 blockade. No unknown pathological features associated with PD-1 blockade were found. Immune suppression in the peritumoral spaces around the residual tumor cells was observed. The amino acid sequences of the T-cell receptors are not significantly shared among the patients. Conclusions The combination of neoadjuvant chemotherapy and PD-1 blockade is safe and feasible, and might indicate an increased MPR and pathological complete response rate. More investigations are needed for the best combination of the neoadjuvant therapy.