Sex-based differences in response to anti-PD-1 or PD-L1 treatment in patients with non-small-cell lung cancer expressing high PD-L1 levels. A systematic review and meta-analysis of randomized clinical trials.

BACKGROUND

In our previous works, we demonstrated that patients' sex affects the efficacy of immune checkpoint inhibitors (ICIs) in patients with several advanced solid tumors. Here, we assessed the sex-based heterogeneity of efficacy of anti-programmed cell death protein 1 (anti-PD-1)/anti-programmed death-ligand 1 (anti-PD-L1) given as monotherapy, for advanced non-small-cell lung cancer (NSCLC) expressing high PD-L1 levels, to evaluate if available evidence supports this therapeutic option for both women and men.

METHODS

We carried out a systematic review and meta-analysis including all randomized, controlled trials testing anti-PD-1/anti-PD-L1 drugs in monotherapy, as first-line treatment of advanced NSCLC expressing high PD-L1 levels. The primary endpoint was the difference in efficacy of anti-PD-1/anti-PD-L1 drugs versus chemotherapy, between men and women, measured in terms of the difference in overall survival (OS) log [hazard ratio (HR)] reported in male and female study participants.

RESULTS

We analyzed four randomized, controlled trials, including 1672 patients, of whom 1224 (73.2%) were men and 448 (26.8%) were women. The pooled OS-HR comparing anti-PD-1/anti-PD-L1 versus chemotherapy was 0.59 [95% confidence interval (CI), 0.50-0.69] for men and only 0.84 (95% CI, 0.64-1.10) for women. The pooled ratio of the OS-HRs reported in men versus women was 0.71 (95% CI, 0.52-0.98; P-heterogeneity: 0.04), indicating a significantly greater effect for men. No heterogeneity among single-study estimates was observed in either male patients (Q = 2.39, P = 0.50, I = 0%) or in female patients (Q = 1.13, P = 0.50, I = 0%).

CONCLUSION

Evidence available indicates anti-PD-1/anti-PD-L1 monotherapy as highly effective in men but not in women, even in NSCLCs expressing high PD-L1 levels. Prospective trials testing sex-based tailored immunotherapy strategies are needed.