A potent antibody therapy could delay the rebound of the HIV virus in patients who are taken off their antiretroviral drugs, scientists have said. This approach could help them in future researches to prevent and cure the infections.

Antiretroviral therapy is currently the most effective therapeutic options for those infected with the HIV virus. The drug combination for sufferers reduces the viral load in their bloodstream to undetectable levels. Yet, it does not completely eliminate the virus with some of it remaining dormant in the body.

On some occasions, some patients may have to stop taking the treatment, for example in cases of drug toxicity, illnesses that prevent oral intake (like gastroenteritis or pancreatitis), surgical procedures or interrupted access to the medication.

The problem is, if antiretroviral therapy is interrupted, the virus can re-emerge over time from hidden reservoirs of latent HIV.

In the latest study, published in Nature, researchers have tested a broad and potent neutralising antibody -known as 3BNC117 - to check whether it could prevent or delay the return of the virus when patients are unable to take their treatment or have to stop it to participate in clinical experiments.

The researchers, from the Rockefeller University in New York, report the results of a phase IIa clinical trial involving 13 HIV-1-infected individuals. The participants were given either two or four doses of the antibody therapy 3BNC117 at an interval of two or three weeks.

The scientists found out that on average the delay in – when the virus reappeared in patients' bloodstream – was 9.9 weeks. Compared with historical controls whose viral load had increased after just 2.6 weeks following antiretroviral therapy interruption, this was a very promising result.

Prevent and cure HIV

These findings could have significant implications for all initiatives seeking to prevent, treat and cure HIV. The antibody could become the drug of choice when antiretroviral therapy when a patient has to stop it for a while.

Additionally, the antibody could be useful in the context of planned long-term interruption of antiretroviral therapy, as is necessary in some controlled clinical trials.

Indeed, several studies are investigating ways to control the virus without using antiretroviral therapy or are looking for methods to eradicate it in the body. Interrupting antiretroviral therapy and monitoring viral rebound over time is an important aspect of these clinical trials to reliably test the effectiveness of the different strategies.

The 3BNC117 antibody could help researchers carry out their work without the patients seeing their viral load increase in just a few weeks.