Background: Aim: To prospectively evaluate cost avoidance during routine conduct of cancer clinical trials in a community based integrated delivery network (IDN) consisting of a health services provider group, a health insurance plan and a hospital system. Only 2%–7% of adult cancer patients participate in clinical trials nationwide [1]. Inadequate funding and concerns about financial viability have been identified as factors that impede clinical trial accrual in the community oncology setting. ‘Cost-avoidance’, defined as dollars that would have been spent to purchase medications but were not spent because of study-related interventions [3] has been proposed as one mechanism to overcome this. Methods: Anti-cancer and hematology drugs provided by intergroup as well as pharmaceutical industry-based trial sponsors to patients enrolled in oncology clinical research were tabulated. Analysis of cost avoidance was restricted to patients covered by the IDNs health plan. Additionally, drugs provided by the trial sponsor were included in the analysis only if they represented a normal standard of care for the disease state. Cost avoidance was defined as the net ingredient cost of the drugs that would have been spent by the health plan for patient care if drugs provided by trial sponsors were not available. Results: Between January 2020 and April 2021, 25 patients covered by the IDN were recruited into clinical trials. Cost savings resulted from 7 targeted and immuno-oncology medications. Net cost avoidance in 2020 was $1,229,798 while that in 2021 till date has been $892,783. The realized cost savings has allowed recruitment of additional clinical research staff as well as expansion of clinical research to rural regional sites served by the IDN. Conclusions: Anticancer drugs provided free of charge by clinical trial sponsors render significant cost savings, ensuring viability and even expansion of oncology clinical research in community based IDNs. References: National Health Expenditure Data. 2018, U.S. Centers for Medicare & Medicaid Services: Baltimore, MD 21244. McDonagh MS, M.S., Naden E., Costs and savings of investigational drug services. American Journal of Health-Systems Pharmacy, 2000. 57: p. 40-43.