Anti-PD-1: When to Stop Treatment

Purpose of Review: Emerging data indicate that immune checkpoint blockade (ICB) in patients with metastatic melanoma can be stopped electively or at the time of toxicity with an acceptable risk for progression. However, the optimal treatment duration remains to be defined. We review published data on treatment duration, outcome after treatment discontinuation, and treatment re-introduction in patients with metastatic melanoma. Recent Findings: Published studies indicate that disease control can be maintained after discontinuation of ICB therapy. Discontinuation of therapy in responders decreases the risk for treatment-related adverse events and lowers the financial burden of ICB. Summary: With the limitation of the limited and heterogenous available published data, elective treatment discontinuation after 1 year of treatment appears safe with an acceptable risk of disease progression. The depth of response is currently the best predictor of prolonged response. The metabolic response on 18F-FDG-PET/CT is expected to gain importance, especially for partial responders.