Project Summary Tumor-associated macrophages (TAMs) usually express an M2 phenotype which enables them to perform immunosuppressive and tumor-promoting functions. Reprogramming these TAMs toward an M1 phenotype could thwart their pro-cancer activities and unleash anti-tumor immunity, but current efforts to accomplish this are nonspecific and elicit systemic inflammation. Our group at Fred Hutchinson Cancer Research Center has developed a targeted nanocarrier that can deliver in vitro-transcribed mRNA encoding M1-polarizing transcription factors to reprogram TAMs without causing systemic toxicity. With the goal of designing the first clinical trial for treating chemotherapy-resistant ovarian cancer patients with this nanodrug, we propose here research that will generate the data required for an IND application. Specifically, we will (1) develop a robust protocol for the scaled-up production of genetic macrophage-programming nanoparticles under GMP- conditions so they can be carried forward into large primate and human studies, (2) identify potential infusion reaction risks, with reference to FDA regulations for nanomedicines, and (3) confirm safety of the nanoparticles for clinical use in a large-animal species. We expect the outcome of the proposed research will help propel this approach into clinical practice for the treatment of advanced ovarian cancer, and provide knowledge to design a broad repertoire of nanotherapeutics that genetically reprogram TAMs as a strategy to treat other tumor types.