The gender of a cancer patient may have an impact on how well immunotherapy works,  a large meta-analysis published in The Lancet Oncology reports.

According to the authors from the Division of Medical Oncology for Melanoma and Sarcoma at the Institute of Oncology in Milan the findings highlight the need for gender-specific analyses to avoid “erroneously extending to women results that are obtained mainly in male patients, which may lead to poorer care, and potentially harm”.

Their meta-analyses involved 20 randomised studies and over 11351 patients (7646 (67%) male and 3705 (33%) female) who had received immune checkpoint inhibitors (ipilimumab, tremelimumab, nivolumab, or pembrolizumab) for a diverse range of advanced or metastatic cancers.

The pooled overall survival HR was 0·72 (95% CI 0·65–0·79) in male patients treated with immune checkpoint inhibitors, compared with men treated in control groups receiving either placebo or another cancer therapy .

In women treated with immune checkpoint inhibitors, the pooled overall survival HR compared with control groups was 0·86 (95% CI 0·79–0·93).

However there was a higher survival benefit for men compared to women.  The pooled reduction of risk of death was was double the size for men compared to women  regardless of the type of cancer and the type of drug taken.

According to the researchers their findings have potential implications for clinical practice and future research.

“The first is that a patient’s sex should be taken into account in the assessment of risk versus benefit when making decisions about treatment strategies, as an important variable predicting the relative benefit achievable with immune checkpoint inhibitors (compared with available standard therapies),” they wrote.

“The second implication of our work is that researchers designing new studies with immunotherapies should guarantee the increased inclusion of of women in clinical trials”.

Writing in a linked Comment, Omar Abdel-Rahman from the Ain Shams University in Egypt and University of Calgary in Canada, said that although the article by Conforti and colleagues was a ‘thought-provoking and hypothesis-generating piece of work’, caution needed to be exercised before jumping directly to radical conclusions and before changing the current standard of care among approved indications for immune checkpoint inhibitors.

“Female patients who are otherwise indicated for treatment with any immune checkpoint inhibitor should not be denied treatment solely on the basis of these findings. Further prospective studies that are disease-specific and that account thoroughly for potential confounders are needed before a final judgment can be made about the effect of the patient’s sex on the efficacy of immune checkpoint inhibitors,” he said.