Association between sex and efficacy of immune checkpoint inhibitors: a systematic review and meta-analysis

Aim: To explore the association between sex and immune checkpoint inhibitors (ICIs). Materials & methods: We assessed the difference in survival outcomes from ICIs between sexes using an interaction test. Results: 108 studies representing 70,243 patients were included. In the first-line setting, the pooled interaction HR was 0.97 (95% CI: 0.91-1.04). In the subsequent-line setting, the pooled interaction HR was 0.85 (95% CI: 0.77-0.95). When ICIs were given as perioperative therapy or as systemic therapy in patients with positive PD-L1 expression, both men and women obtained equal survival benefits. Conclusion: Both sex, line of therapy, cancer (sub)type and PD-L1 status should be taken into account in the assessment of risk versus benefit when deciding to offer ICIs to patients. There are many differences between men and women, and whether these differences also affect the efficacy of immune checkpoint inhibitors is important because immune checkpoint inhibitors have been widely accepted as standardized treatments for patients with malignant tumors. Previous studies have reported conflicting results. This research was conducted to reassess this sex disparity with additional available reports. We found that both men and women can benefit from immune checkpoint inhibitors, while sex should be taken into account when deciding to offer immune checkpoint inhibitors to patients who have already been heavily treated.