Abstract Eighty-five percent of patients receive medical care in cancer centers without National Cancer Institute (NCI) designation or significant ongoing research. The ability to access fresh tumor tissue for immediate functional testing is now available with appropriate logistical coordination. Cryopreservation of these tissues also allows testing to be done at a later date. We hypothesize that patient access to and ownership of each individual's tissues will facilitate personalized testing, thus bridging the chasm between research and the clinical cancer care for the individual patient. The PIONEER Initiative stands for Precision Insights On N-of-1 Ex vivo Effectiveness Research. In this Initiative we save cancerous tissue for any patient at any location, with subsequent cryopreservation and functional testing as needed and as able within an environment in which neither are standard. Our endpoint was to determine if this process serves to alter care for individual patients, and to what degree. The SpeciCare PIONEER Initiative: Precision Insights On N-of-1 Ex Vivo Effectiveness Research Based on Individual Tumor Ownership Trial (MYCT001) received human subjects IRB approval (Approval Number: 33943/1) from Quorum Review. The PIONEER Initiative is our lead clinical trial designed to provide the foundation for subsequent adaptive trials. Our mission with this trial was to demonstrate the utility of carrying out functional precision medicine in that cohort of patients who receive local cancer care at institutions that do not have significant research capabilities or are not NCI-designated cancer centers. Most cancer patients (~85%) are in this category. It is imperative to open the possibility of the best-in-class functional precision medicine testing to these patients. Core aspects of the PIONEER Initiative involve scaling up this process to approximately 200 patients, showing that our proof of concept in a more limited set of patients can ultimately scale to arbitrarily large numbers of patients. We see this capacity filling an important unmet need within the cancer community. The primary endpoint was the return of actionable information to positively impact care as assessed by the patient's clinical team and the patient. The underlying basic assumption of the PIONEER Initiative is that the ability to receive the best in cancer care should not come with restriction as to location, age, or medical condition. The PIONEER Initiative design facilitates inclusion of subjects across all these divides, thus providing beneficence to all participants. Among the 60 patients whose tumors had ex vivo drug testing performed, none of the data was included in the clinical decision making of the healthcare team. We conclude that physicians are not adequately prepared to use ex vivo drug testing data and the more likely acceptance of molecular characterization is primarily driven by genomic sequencing. Citation Format: Ken Dixon, Jared James Barrott, David Booker. PIONEER initiative: Providing patient access to functional precision medicine [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 4960.