Overall survival (OS) remains the gold standard endpoint in oncology trials, but the FDA’s August 2025 draft guidance highlights new complexities in assessing survival in an era of highly effective therapies, longer patient lifespans, and confounding crossover or subsequent treatments. Recent high-profile cases where promising early efficacy endpoints masked OS detriments have catalyzed this regulatory evolution. The guidance now recommends that all randomized oncology trials collect and assess OS data, even when using surrogate endpoints as primary measures, thus fundamentally shifting trial planning expectations. OS is both an efficacy and safety endpoint in that it can measure both prolongation of life and reveal drug-related toxicities that may offset therapeutic benefits. The new guidance necessitates careful statistical planning, pre-specified analyses, and sensitivity assessments in clinical trials. This session will hear from industry leaders as they discuss how the FDA's guidance on assessing overall survival will shape the future of oncology clinical trials.