Enhanced lung delivery of an immunostimulatory duplex RNA augments the antitumor activity by reshaping systemic cytokine pharmacodynamics

Abstract The organ-specific enrichment of drug delivery vehicles, such as lipid nanoparticles (LNPs), can be leveraged to concentrate drugs at disease sites to increase efficacy and limit toxicity. For immunostimulatory therapeutics, however, tissue accumulation beyond diseased sites may also shape drug activity by determining which organs and cell populations first sense the agonist and initiate downstream immune responses. Here, we show that the anticancer efficacy of an immunostimulatory duplex RNA (dsRNA) can be augmented using LNPs that are formulated to preferentially target the lung, which dictates the systemic pharmacodynamics of the cytokines it elicits. The immunostimulatory dsRNA was formulated into LNPs engineered for either enhanced liver-(LiverLNPs) or lung-(LungLNPs) based delivery, matched for size, encapsulation efficiency, and in vitro potency. In mice, delivery of dsRNA in LungLNPs enhanced uptake into endothelial, epithelial, and resident immune cells populations and induced substantially higher circulating levels of type I, type III interferons and proinflammatory cytokines than dsRNA formulated in LiverLNPs. This significant systemic response induced by lung-enhanced delivery required competent retinoic acid-inducible gene I and Toll-like receptor 7 signaling. Functionally, LNPs that preferentially targeted the lungs induced significantly greater suppression of tumor growth in both subcutaneous and metastatic models of melanoma. LungLNP/dsRNA also induced cytokine secretion and inhibited tumor cell proliferation in a human lung cancer-on-a-chip model. Together, these results establish that pulmonary exposure can alter systemic pharmacodynamics and therapeutic activity of immunostimulatory RNA. Competing Interest Statement E. A-L., A.M.C., K.E.C., W.M.S, D.E.I. and N.A are listed as inventors on a patent application filed by Harvard Medical School that describes RNA-1 anticancer activity; D.E.I is listed as inventor on a patent filed by Harvard Medical School that describes RNA-1 dimers and D.E.I is also listed as inventor on a patent filed by Harvard Medical School that describes RNA-1 full length.