Effects of Anti-PD1 Adjuvant Checkpoint Blockade Immunotherapy on Atypical/Dysplastic Nevi

Given the established efficacy of anti-PD1 therapy as an adjuvant treatment in both advanced nodal and earlier stage deep primary node negative melanoma, this study hypothesizes that anti-PD1 therapy may provide a basis for effective therapeutic prevention. To study if anti-PD1 therapy can help prevent the development of melanoma, this study will examine its effects upon atypical/dysplastic nevi, which are well established as non-obligate pre-cursor lesions that are markers of increased risk of melanoma. This single agent, adjuvant study will evaluate the impact of adjuvant anti-PD1 therapy on morphology, histopathology, immunologic/molecular features, and gene expression of atypical/dysplastic nevi present in patients with stage IIB-III melanoma. This study aims to determine if anti-PD1 therapy will increase CD8 T cell responses to melanoma antigens, resulting in immune surveillance and anti-tumor immune responses within A/DN. It postulates that in response to anti-PD1 therapy, the aggregate pigmentation of total nevi including atypical/dysplastic nevi and benign melanocytic nevi will decrease with a measurable morphologic response. This study also asserts that there will be histopathologic changes within A/DN including increased density of immune infiltrate and increased presence of regression features. Increased anti-tumor immune response measured by increased CD8, IFN-y, and PD-1 expression within nevi is anticipated, along with a decrease in genes involved in pathways of melanomagenesis, pigmentation, and inflammation.