115 Background: Cancer drug repositories (CDRs) have the potential to minimize cancer medication waste while improving medication access to patients in need. Despite multiple states having legislation allowing for CDR programs, implementation remains suboptimal. The first CDRs to launch in Michigan were a fortuitous result of the support provided in embedding clinical pharmacists into community oncology practices via the Pharmacists Optimizing Oncology Care Excellence in Michigan, POEM, program. We describe these grassroot efforts as well as barriers to sustainability, ultimately resulting in formation of a statewide CDR Network, YesRx. Methods: This qualitative analysis of barriers and facilitators was conducted from interviews with Michigan’s first CDRs. Virtual group meetings were conducted monthly for 6-months from January 2023 – June 2023. Meetings were led by the coordinating center team of POEM. Workgroup attendees included POEM pharmacists who established the first 3 CDR programs in the State, a medical oncologist and longstanding advocate of CDRs, and a patient representative. Brainstorming sessions included open ended questions on experiences to date, benefits of CDR programs, barriers to growth, limitations in current CDR models, and beneficial areas for support. Interview findings were categorized as barriers or facilitators of site-specific implementation and recommendations for CDR model optimization. Results: All 3 CDRs reported positive outcomes from initiating the CDRs related to patient benefit and physician satisfaction. Items reported as challenges/barriers in the sustainability of individual site-managed CDRs: space (inventory growth exceeded designated storage capacity), complexity of inventory tracking, resources (staff and financial), inability to search state-wide for available inventory, inability to easily transfer medications between CDR sites (due to cost, documentation, and staff), inability to ship medications directly to a patient’s home, inability to serve cancer patients across the State who may be in need of medication or interested in donating. The top recommendations for CDR model optimization formed by this workgroup were a centralized, shared database of CDR inventory across the State, support for CDR medication transfers, and additional resource and storage capabilities. YesRx, a nonprofit service organization, was founded in July 2023 in collaboration with the first 3 CDRs to address the experienced barriers resulting in exponential state-wide access. Conclusions: Grassroot efforts of community-based clinical oncology pharmacists resulted in the first CDR programs in Michigan and their experiences guided the launch of a statewide network of CDRs created to expand cancer medication access for vulnerable and underserved people and communities.