The effect of gender on the clinical outcome of PD-1/PD-L1 inhibitor in advanced lung cancer patients

BACKGROUND: Programmed death protein-1/ligand-1 (PD-1/L1) inhibitors have widely used in the treatment of lung cancer. Some literatures indicated that different gender might not have equal immune response, but no agreement have reached on the issue. Hence, we performed a systematic review and meta-analysis that examine the effect of gender on the clinical outcome of PD-1/PD-L1 inhibitor in advanced lung cancer patients. METHODS: Related database and conferences were searched. Studies that reported the relationship between gender and the overall survival (OS) or progression-free survival (PFS) of PD-1/L1 inhibitor were included. Meta-analysis was conducted to obtain pooled hazard ratios (HRs) with 95% CI. RESULTS: We included 34 studies with 11,883 lung cancer patients. Meta-analysis showed that PD-1/PD-L1 inhibitors significantly prolonged the OS (males: HR 0.71, 95%CI 0.66–0.77; females: HR 0.72, 95%CI 0.63–0.82) and PFS (males: HR 0.60, 95%CI 0.55–0.66; females: HR 0.72, 95%CI 0.62–0.84) versus chemotherapy. The clinical benefit (OS HR: 0.99; PFS HR: 0.83) was not statistically significant between males and females. In patients treated with cemiplimab, male patients had a better OS (0.53, 95%CI 0.42–0.66) and PFS (OS 1.51, 95%CI 0.80–2.82) compared with female patients, but the small number of female patients precludes us from drawing any firm conclusions in female subpopulations. CONCLUSION: The clinical benefit of PD-1/PD-L1 inhibitors was not statistically significant between males and females during the treatment of lung cancer. In the future, researchers who are designing new immunotherapy studies should ensure a larger inclusion of women in trials, to avoid erroneously extending to women results that are obtained mainly in male patients.