Complete substitution with modified nucleotides in self-amplifying RNA suppresses the interferon response and increases potency.

McGee, Joshua E; Kirsch, Jack R; Kenney, Devin; Cerbo, Faith; Chavez, Elizabeth C; Shih, Ting-Yu; Douam, Florian; Wong, Wilson W et al. · Nat Biotechnol · 2025

basic_science · Level V

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Abstract

The use of modified nucleotides to suppress the interferon response and maintain translation of self-amplifying RNA (saRNA), which has been achieved for mRNA, has not yet succeeded. We identify modified nucleotides that, when substituted at 100% in saRNA, confer innate immune evasion and robust long-term protein expression, and when formulated as a vaccine, protect against lethal SARS-CoV-2 challenge in mice. This discovery advances saRNA therapeutics by enabling prolonged protein expression at low doses.

Medical subject headings