Association of Gender with Efficacy of Immunotherapy in Metastatic Melanoma

Pre-clinical data from animal models suggest that the anti-tumor efficacy of immune checkpoint blockade agents may be influenced by gender specific sex hormones. However, recent meta-analyses of clinical data aimed at addressing the impact of gender on response to these agents have demonstrated conflicting results. Given the discordant evidence, we sought to evaluate the association of gender with the receipt and efficacy of modern immunotherapies in patients with metastatic melanoma. This retrospective cohort study used the National Cancer Database to identify patients who were ≥18 years old with Stage IV melanoma from 2011 to 2015. Patterns of utilization of immunotherapy, including by gender, were assessed using multivariable logistic regression. A multivariable Cox proportional hazards model, including an interaction term between the receipt of immunotherapy and gender, was used to evaluate whether gender modified the association of receipt of immunotherapy with hazards of death. 11,944 patients met study inclusion criteria. Of these, 8,093 (68%) were males and 3,851 (32%) were females. 2,930 (25%) patients received immunotherapy while 9,014 (75%) did not. There was no statistically significant difference in the receipt of immunotherapy between males and females. On multivariable analysis, receipt of immunotherapy was associated with a survival benefit in both males and females. However, a statistically significant difference in efficacy of immunotherapy based on gender was not observed (p interaction =0.422). Utilizing a real world cohort of patients derived from a national cancer registry, gender was not associated with differences in immunotherapy survival outcomes in patients with metastatic melanoma.