Discontinuation of anti‐PD‐1 monotherapy in advanced melanoma—Outcomes of daily clinical practice

There is no consensus on the optimal treatment duration of anti‐PD‐1 for advanced melanoma. The aim of our study was to gain insight into the outcomes of anti‐PD‐1 discontinuation, the association of treatment duration with progression and anti‐PD‐1 re‐treatment in relapsing patients. Analyses were performed on advanced melanoma patients in the Netherlands who discontinued first‐line anti‐PD‐1 monotherapy in the absence of progressive disease (n = 324). Survival was estimated after anti‐PD‐1 discontinuation and with a Cox model the association of treatment duration with progression was assessed. At the time of anti‐PD‐1 discontinuation, 90 (28%) patients had a complete response (CR), 190 (59%) a partial response (PR) and 44 (14%) stable disease (SD). Median treatment duration for patients with CR, PR and SD was 11.2, 11.5 and 7.2 months, respectively. The 24‐month progression‐free survival and overall survival probabilities for patients with a CR, PR and SD were, respectively, 64% and 88%, 53% and 82%, 31% and 64%. Survival outcomes of patients with a PR and CR were similar when anti‐PD‐1 discontinuation was not due to adverse events. Having a PR at anti‐PD‐1 discontinuation and longer time to first response were associated with progression [hazard ratio (HR) = 1.81 (95% confidence interval, CI = 1.11‐2.97) and HR = 1.10 (95% CI = 1.02‐1.19; per month increase)]. In 17 of the 27 anti‐PD‐1 re‐treated patients (63%), a response was observed. Advanced melanoma patients can have durable remissions after (elective) anti‐PD‐1 discontinuation.