Importance Immune checkpoint inhibitors have demonstrated atypical response patterns,
which may not be fully captured by conventional response criteria. There is a need to better
understand the potential benefit of continued immune checkpoint inhibition beyond
progression. Objective To evaluate the safety and potential benefit of nivolumab (anti–
programmed cell death receptor 1) monotherapy beyond Response Evaluation Criteria in
Solid Tumors (RECIST) v1. 1-defined progression. Design, Setting, and Participants Pooled …