Primary Resistance to PD-1-Based Immunotherapy-A Study in 319 Patients with Stage IV Melanoma.

Background: Primary resistance to immunotherapy can be observed in approximately 40-65% of the stage IV melanoma patients treated with immune checkpoint inhibitors. A minority of the patients receive a second-line therapy, and the clinical benefit is small.

Patients And Methods: Stage IV melanoma patients treated with first-line PD-1-based immunotherapy between January 2015 and December 2018 were investigated.