Conforti F, et al. - Researchers assessed the difference in the efficacy of immune checkpoint inhibitors as cancer treatment between men and women. Though the magnitude of effect was sex-dependent, improvement in overall survival could be achieved with immune checkpoint inhibitors in patients with advanced cancers such as melanoma and non-small-cell lung cancer.

Methods

• Researchers performed a systematic search of PubMed, MEDLINE, Embase, and Scopus, from database inception to Nov 30, 2017, and identified randomized controlled trials of immune checkpoint inhibitors (inhibitors of PD-1, CTLA-4, or both) that had available hazard ratios (HRs) for death according to patients' sex.
• They also reviewed English-language abstracts and presentations from all major conference proceedings, excluding non-randomized trials.
• The difference in efficacy of immune checkpoint inhibitors between men and women, measured in terms of the difference in overall survival log (HR) reported in male and female study participants, was considered as the primary endpoint.
• They used a random-effects model to calculate the pooled overall survival HR and 95% CI in men and women and assessed the heterogeneity between the two estimates using an interaction test.

Results

• Researchers identified 7,133 studies, only 20 eligible randomized controlled trials of immune checkpoint inhibitors (ipilimumab, tremelimumab, nivolumab, or pembrolizumab) reported overall survival according to patients' sex.
• They analyzed a total of 11,351 patients with advanced or metastatic cancers (7,646 [67%] men and 3,705 [33%] women); the most common types of cancer were melanoma (3,632 [32%]) and non-small-cell lung cancer (3,482 [31%]).
• Relative to men treated in control groups, the observed pooled overall survival HR was 0.72 (95% CI 0·65–0·79) in male patients treated with immune checkpoint inhibitors.
• They found that the pooled overall survival HR in women treated with immune checkpoint inhibitors was 0.86 (95% CI 0·79–0·93), relative to control groups.
• A significant difference was noted in efficacy between men and women treated with immune checkpoint inhibitors (p=0·0019).