PROJECT SUMMARY Decades of modulating the anti-cancer activity of fluoropyrimidine drugs (FPs) thru schedule optimization, biochemical modulation, and drug combinations have provided a significant, but limited, survival advantage for treating colorectal cancer (CRC) patients with locally advanced or metastatic disease (mCRC). However, outcomes remain poor for patients with mCRC and since targeted therapies and immunotherapies provide only a limited benefit to a sub-set of CRC patients, new approaches are urgently needed. Deep Creek Pharma together academic partner Wake Forest School of Medicine (WFSM) is developing CF10, the first DNA-based FP polymer, as an improved treatment for CRC. In pre-clinical studies through Phase 1 STTR support, we have demonstrated that CF10 is much more potent than 5-FU to CRC cells and demonstrated improved survival relative to 5-FU in multiple colon tumor models in rodents. Further, CF10 displayed reduced systemic toxicities relative to 5-FU making it a strong candidate for clinical development. We have also established CF10 displays distinct pharmacological and mechanistic properties relative to conventional FP drugs. Based on these findings, DeepCreek Pharma and WFSM/Gmeiner Lab propose to jointly investigate CF10 as a candidate for clinical development. A major unmet need is treatment of mCRC that is refractory to FOLFOX (5-FU, Leucovorin (LV), oxaliplatin), and other front-line therapies for mCRC. The proposed research in phase II will therefore focus on (Aim 1) Developing CF10 lipid nanoparticles (LNPs) and testing for improved activity, including in a therapy-resistant CRC liver metastasis model. LNP formulation has proven to be a robust delivery strategy for multiple nucleic acid drugs, and identifying a preferred LNP formulation will promote CF10 clinical development. In Aim 2 of the Phase II studies we will perform safety pharmacology studies of CF10 and CF10:LNPs in rodents while in Aim 3 we will evaluate pharmacokinetics (PK) and biodistribution in non-human primates (NHPs). Studies in NHPs accurately reflect human physiology and metabolism and are particularly important for regulatory apprval. Collectively, our Phase II STTR studies will provide critical data for to advance CF10 into clinical trials and ultimately its commercialization.