Enhanced HIV-1 Control After Antibody Therapy is Associated with Autologous Antibodies and Reservoir Clearance in the RIO trial

RIO is an ongoing double blind randomized placebo controlled human trial in which participants that started antiretroviral therapy (ART) during primary or early-stage infection underwent treatment interruption and were randomly assigned to a group receiving one or two doses of two long acting broadly neutralizing antibodies 3BNC117-LS and 10-1074-LS (Arm A), or saline (Arm B). The two arms differed significantly in time to viral rebound, ART restart and number of individuals that remained off therapy after 96 weeks (p=0.001) ¹ . Here we report on the relationship between viremic control, the latent HIV-1 proviral reservoir, rebound viruses and their sensitivity to the infused and autologous antibodies. Pre-infusion reservoir measurements showed low levels of intact proviral HIV-1 DNA in circulating CD4+ T cells in both arms. The rebounding viruses in participants that received the antibodies, showed significant selection for resistance to 10-1074-LS but not to 3BNC117-LS. Notably, there was a significant correlation between initial reservoir sensitivity to autologous antibodies and to 10-1074 and time to rebound. Finally, comparison of pre-infusion and pre-rebound HIV-1 proviral reservoir in participants that received antibodies showed that the reservoir of intact proviruses decayed faster than earlier reports with a half-life of 0.65 years.