Investigating Low Survival Rates in Patients With Vulvar/Vaginal Melanomas

Annelise Wilhite, MD, of the University of South Alabama Health, discusses a clinical investigation of survival in patients with vulvar/vaginal melanomas.

In a study, patients with vulvar/vaginal melanoma were treated with immunotherapeutic agents like pembrolizumab (Keytruda), nivolumab (Opdivo), and ipilimumab (Yervoy) had significantly shorter survival compared with patients with cutaneous melanoma treated with the same immunotherapies. The difference in survival between the vulvar/vaginal melanoma and cutaneous melanoma population was nearly 1 year and 6 months, says Wilhite. The findings warrant the development of new therapies for the vulvar/vaginal melanoma patient population.

Further study into why patients with vulvar/vaginal melanoma do not have longer survival showed that high tumor mutational burden (TMB) was absent in the vulvar/vaginal melanoma tumors compared with the cutaneous population, in which 50% of patients had high TMB. The vulvar/vaginal melanoma group also had significantly lower PD-L1 expression, and the microenvironment had significantly lower levels of effector T cells and immune-promoting macrophages.

In terms of genetic mutations, a low number of BRAF mutations were observed in the vulvar/vaginal melanoma cohort, but there was a higher rate of KIT mutations in these patients. Wilhite explains that the presence of KIT mutations could lead to a targeted therapy opportunity in the future.