RIO study

4 April 2025. Related: News, Resources.

The RIO study was launched in 2021 to see whether immune-based therapy (called bNAbs) can be used instead of HIV treatment (ART).

First results have just been presented at the CROI 2025 and BHIVA 2025 conferences.

• CROI 2025: RIO study: Dual-bNABs keep viral load undetectable off-ART – plus a potential first case of vaccine-like HIV remission

RIO involves giving two long-acting bNAbs or a placebo by infusion and then stopping ART, with close monitoring.

ART was then restarted after viral load rebounded above either 1000 for more than 6 weeks or if confirmed once above 100,000.

The study was open to people who started HIV treatment soon after they became HIV positive.

The study opened in June 2021 after participants have had COVID-19 vaccines. It will run for two years. Although enrolment was due to start in Spring 2020, the study was delayed for a year because of COVID-19.

This short video below explains what was involved in this study.

Video: the RIO Trial – using a new immune-based therapy to treat HIV (5 minutes)

First results

The first results from RIO were presented at CROI 2025.

• Q&A on the main results.
  https://i-base.info/htb/50971

• CROI 2025: RIO study: Dual-bNABs keep viral load undetectable off-ART – plus a potential first case of vaccine-like HIV remission

Other links

RIO trial website

Please contact the study team if you are interested in joining RIO. This link also includes a map showing the study sites in London and Brighton.

Journal article explaining the protocol for RIO in detail.