Smoking status-based efficacy difference in anti-PD-1/PD-L1 immunotherapy: a systematic review and meta-analysis.

Aim: This study aimed to evaluate the relationship between smoking status and efficacy of PD-1/PD-L1 inhibitors compared with conventional agents. Materials & methods: We reviewed Phase II/III trials of PD-1/PD-L1 inhibitors that reported hazard ratio (HR) in current/former and never smoking patients. Results: 15 qualifying trials comprising 9073 patients were eligible in this study. Compared with conventional agents, PD-1/PD-L1 inhibitors correlated with prolonged progression-free survival (HR: 0.73; 0.58-0.92) and overall survival (HR: 0.75; 0.71-0.80) in current/former smoker patients but not in never-smoker patients (HR: 1.15 and 0.86 for progression-free survival and overall survival, respectively; both p > 0.05) irrespective of cancer type, target of experimental agents and treatment strategy. Conclusion: There exit smoking status-based efficacy difference in anti-PD-1/PD-L1 immunotherapy.