BACKGROUND: Randomized controlled trials (RCTs), the gold standard of safety and efficacy evidence, are conducted in select patients that may not mirror real-world populations. As a result, healthcare decision makers may have limited information when making formulary decisions, especially in oncology, given accelerated regulatory approvals and niche patient populations. Real-world evidence (RWE) studies may help address these knowledge gaps and help inform oncology formulary decision making. OBJECTIVE: To assess US payer perceptions regarding the use and relevance of RWE in informing oncology formulary decisionmaking. METHODS: A national survey containing single-answer, multiple-answer, and free-response questions evaluated 4 key areas: (1) the value of RWE, (2) barriers to RWE, (3) sources of RWE, and (4) use of RWE in outcomes-based contracting. The survey was distributed to 221 US payers through the Academy of Managed Care Pharmacy (AMCP) Market Insights program in February 2020. Ten additional respondents were invited to discuss the survey results. The survey results were presented primarily as frequencies of responses and were evaluated by the respondent's plan size, type, and geography (regional vs national). Differences in responses for categorical data were compared using a Pearson Chi-Square or a Fisher's Exact test. Two-tailed values are reported and a level of ≤ 0.05 was used to indicate statistical significance. RESULTS: The national survey had a 45.9% response rate, with 106 payers responding. Most were from managed care organizations (MCOs; 47.5%) and pharmacy benefit managers (PBMs; 37.4%), with 54.5% from large plans (≥ 1 million lives) and 45.5% from small plans (< 1 million lives). Respondents were largely pharmacists (89.9%), with 55.6% overall indicating their job was a pharmacy administrator. Most (84.9%) used RWE to inform formulary decisions in oncology to support comparative effectiveness in the absence of head-to-head clinical trials (4.1 on a scale of 1 = Not At All Useful to 5 = Extremely Useful) and validation of National Comprehensive Cancer Network (NCCN) recommendations (4.0). Almost half (41.5%) used RWE results to inform off-label usage decisions. Payers valued RWE pre-launch to inform formulary and contracting decisions and desired real-world comparative effectiveness data post-launch to validate coverage decisions. However, the majority of payers (54.7%) did not conduct their own real-world studies. Commonly considered RWE sources included claims data (79.2%), medical records (68.9%), prospective cohort studies (60.4%), patient registries (36.8%), and patient outcome surveys (33.0%). Barriers to conducting internal RWE studies included the lack of resources and personnel, analytic capabilities, appropriate in-house data, and perceived value in conducting analyses. Payers expressed interest in using outcomes-based contracting in oncology; few have direct experience, and operationalizing through value measurement is challenging. CONCLUSIONS: RWE providing comparative treatment data, validation of NCCN treatment recommendations, and information on off-label usage are appreciated pre launch with post launch validation. DISCLOSURES: Pfizer provided funding for this research, and employees of Pfizer led the development of the survey and contributed to the manuscript as authors. Arondekar and Niyazov are employees of Pfizer; Oderda, Biskupiak, and Brixner are managers of Millcreek Outcomes Group and were paid as consultants on this project. Burgoyne was a consultant for Pfizer on this project. Malone was paid by Millcreek Outcomes as a consultant on this project.