Ongoing Clinical Trials of Nonviral siRNA Therapeutics

Short interfering RNAs (siRNA) are a powerful class of genetic medicines whose clinical translation can be hindered by their suboptimal delivery properties in vivo. Here, we provide a clinically focused overview that summarizes ongoing siRNA clinical trials from the perspective of innovations in nonviral delivery strategies. More specifically, our review begins by highlighting the delivery barriers and physiochemical properties of siRNA that make it challenging to deliver it in vivo. We then provide commentary on specific delivery strategies, including sequence modification, siRNA ligand conjugation, and nanoparticle and exosomal packaging, each of which can be used to control the delivery of siRNA therapies in living systems. Last, we provide a summary table of ongoing siRNA clinical trials which also highlights the indication of use, target, and National Clinical Trial (NCT) number associated with each entry. In writing this review, our work aims to highlight the key challenges and strategies for effective nonviral siRNA delivery in vivo, while simultaneously summarizing information on ongoing clinical trials for siRNA therapy in humans.