e16550 Background: Substantial uncertainty exists about the benefits and harms of many oncology drugs in real-world settings, creating challenges for patients, providers, payers, and policymakers. Comparative effectiveness research (CER) can provide evidence to support this decision-making. However, oncology CER often lacks standards, making results difficult to cross-compare and interpret. Methods: The Center for Medical Technology Policy (CMTP) developed a guidance document with the goal of setting CER standards to improve the validity, relevance, and consistency of CER for anti-neoplastic agents. The recommendations are aimed at assisting trial designers in developing post-approval clinical studies for new indications of oncology drugs and were developed using expert input from semi-structured interviews and an in-person meeting. Results: Stakeholders included advocacy groups, medical oncologists, pharmaceutical companies, the Food and Drug Administration (FDA), the Centers for Medicare & Medicaid Services (CMS), the National Cancer Institute (NCI), ASCO, foreign health technology assessment agencies, payers, drug compendia, and statisticians. Recommendations are in four categories: trial design and data analysis; patient and site recruitment; comparators; and outcomes. Examples of the recommendations include: 1) Whenever feasible, actual survival rather than a surrogate for survival should be used as the primary outcome; however, when a surrogate is necessary, then evidence for the validity of the surrogate within the targeted indication should be provided; and 2) a clinically-relevant dosing regimen for the comparator drug that allows for evidence-based comparisons should be used. Conclusions: In contrast to FDA guidance for conducting trials for regulatory approval, this guidance is directed towards post-approval trials for decision makers, which may help maximize the generation of evidence that would be of relevance to decision makers.