Nature Medicine: host and infused antibodies both linked to longer ART-free HIV control in RIO analyses

A Nature Medicine News & Views published on 13 October 2026 summarizes secondary and exploratory analyses from the phase 2 RIO trial: both host (autologous) antibodies and infused broadly neutralizing antibodies (bNAbs) appear to help delay HIV rebound after antiretroviral therapy (ART) interruption — findings detailed in an open-access paper by Fumagalli and colleagues.

Study type

RIO is a randomized, double-blind, placebo-controlled phase 2 trial (NCT04319367) in 68 adult men who started ART during primary or early infection. Participants received long-acting bNAbs 3BNC117-LS and 10-1074-LS or saline before analytical treatment interruption. The primary clinical result (published separately in Lancet HIV) already showed delayed rebound with bNAbs versus placebo.

Key secondary findings

In the antibody arm, participants with measurable baseline autologous neutralizing activity against reservoir viruses had a mean time to ART restart of about 108 weeks versus 27.5 weeks without it (small subgroups). Time to restart also correlated with greater initial reservoir sensitivity to 10-1074. Intact — but not defective — proviral DNA declined over follow-up in the bNAb arm more than in placebo in paired samples. Rebound viruses often selected resistance to 10-1074.

Limitations

Analyses of autologous antibodies were partly non-prespecified and limited to participants with recoverable reservoir sequences; all enrolled participants were men, mostly white; associations are correlative, not proof of mechanism; blood sampling may miss tissue reservoirs; this is not a cure and not personal medical advice. Talk with an HIV clinician about any treatment decisions.