A Lung-Targeted RNAi Therapeutics Delivery Platform Compatible With Subcutaneous (s.c.) Administration Mediates Pulmonary RAGE Silencing In Rodents And Nonhuman Primates

Introduction: Our pulmonary Targeted RNAi Molecule (TRiM^TM) delivery platform facilitates selective delivery of therapeutic siRNAs to the lung epithelium via an integrin α_vβ₆ targeting moiety, mediating durable gene silencing following inhaled dosing. Here, we demonstrate that the pulmonary TRiM^TM platform is also compatible with subcutaneous administration and is capable of effectively silencing lung expression of the receptor for advanced glycation end-products (RAGE) in rats and nonhuman primates. Methods: Rats received s.c. injections of integrin-targeted siRNA specific for silencing RAGE mRNA. Cynomolgus monkeys received injections of ARO-RAGE, an RNAi therapeutic in Phase 1/2a trials for pulmonary inflammation. Lung expression of RAGE mRNA was quantified by RT-qPCR. Soluble RAGE (sRAGE) protein derived from full-length receptor was monitored by immunoassay in serial serum samples. Results: Lung mRNA was silenced in a ligand- and dose-dependent manner (reaching approximately 70-80% knockdown within a week) after single s.c. injection of an integrin-targeted RAGE siRNA conjugate in rats. Weekly, biweekly or monthly dosing maintained deeper lung RAGE and sRAGE silencing, with recovery to baseline expression occurring about 7 weeks post cessation of dosing. Similar observations were made in cynomolgus monkeys receiving s.c. ARO-RAGE, with weekly 10 mg/kg doses maintaining sRAGE silencing. Conclusion: Integrin-targeted siRNAs for RAGE silencing effectively kept lung RAGE knockdown when dosed subcutaneously, offering an alternative route of administration for ARO-RAGE and future pulmonary RNAi therapeutics.