Durable suppression of viremia by lipid nanoparticle-formulated RNA encoding for a highly potent HIV-1 neutralizing antibody

Recombinant broadly neutralizing antibodies (bNAbs) are promising tools to treat and prevent HIV-1 infection but are associated with manufacturing challenges. To overcome this limitation, we encoded the potent bNAb 1-18-LS on RNA (1-18-LS RibobNAb) for delivery via lipid nanoparticles (LNPs). Indicating high in vivo antibody expression, a 30 µg RNA-LNP intravenous injection resulted in an average peak 1-18-LS RibobNAb serum concentration of 1,061 µg/mL in human neonatal Fc receptor-transgenic mice. Notably, weekly 30 µg RNA-LNP doses maintained higher trough bNAb levels than 500 µg protein injections. Highlighting potent antiviral activity, RNA-LNP-mediated 1-18-LS RibobNAb monotherapy of viremic HIV-1 _YU2 -infected humanized mice resulted in durable HIV-1 suppression without emerging viral escape. Importantly, 1-18-LS RNA-LNP treatment also fully controlled infection after interruption of antiretroviral therapy in humanized mice infected with different patient-derived polyclonal HIV-1 isolates. Our findings provide a proof-of-principle for effective RNA-mediated bNAb immunotherapy of HIV-1 infection.