Survival in Male vs Female Patients Receiving Immune Checkpoint Inhibitors


Key Points

  • Pooled overall survival hazard ratios for immune checkpoint inhibitor vs control treatment were 0.72 for men and 0.86 for women.
  • The difference in survival benefit was statistically significant.   

In a systematic review and meta-analysis reported in The Lancet Oncology, Conforti et al found a significant difference in overall survival benefit favoring male vs female patients receiving immune checkpoint inhibitor therapy for advanced cancers.

Study Details

The study involved database searches of the literature through November 2017 for randomized controlled trials of immune checkpoint inhibitors that included hazard ratios (HRs) for death according to patient sex. A total of 20 trials of ipilimumab (Yervoy), tremelimumab, nivolumab (Opdivo), and pembrolizumab (Keytruda) were identified, including a total of 11,351 patients with advanced or metastatic disease. Of these, 7,646 (67%) were men and 3,705 (33%) were women; the most common types of cancer were melanoma (n = 3,632, 32%) and non–small cell lung cancer (n = 3,482, 31%).

Among all patients, 2,881 were enrolled in ipilimumab trials; 1,226 in tremelimumab trials; 3,893 in nivolumab trials; 3,209 in pembrolizumab trials; and 142 in a nivolumab plus ipilimumab trial.

Survival by Sex

Among all patients, the pooled overall survival HRs were 0.72 (95% confidence interval [CI] = 0.65–0.79) for immune checkpoint inhibitor vs control treatment in male patients and 0.86 (95% CI = 0.79–0.93) in female patients. The difference in efficacy between men and women receiving immune checkpoint inhibitors was significant (P = .0019), with the pooled interaction HR for men vs women being 0.85. Subgroup analyses for cancer type (P = .72 for heterogeneity); line of treatment (P = .77 for heterogeneity); type of immune checkpoint inhibitor (anti–programmed cell death protein 1 [PD-1], anti–CTLA-4; P = .40 for heterogeneity); and control group (immunotherapy, no immunotherapy; P = .72) showed better HRs for men vs women for each subgroup, with the heterogeneity test for the sex interaction being nonsignificant in each subgroup.

The investigators concluded, “Immune checkpoint inhibitors can improve overall survival for patients with advanced cancers such as melanoma and non–small cell lung cancer, but the magnitude of benefit is sex-dependent. Future research should guarantee greater inclusion of women in trials and focus on improving the effectiveness of immunotherapies in women, perhaps exploring different immunotherapeutic approaches in men and women.”

The investigators reported that there was no funding for the study.

Fabio Conforti, MD, of the Division of Medical Oncology for Melanoma & Sarcoma, European Institute of Oncology, Milan, is the corresponding author for The Lancet Oncology article. 

The content in this post has not been reviewed by the American Society of Clinical Oncology, Inc. (ASCO®) and does not necessarily reflect the ideas and opinions of ASCO®.