New HIV Vaccine Candidate Shows Promise In Early Trials

A new HIV vaccine candidate has shown promise in early-stage clinical trials, successfully generating broadly neutralising antibodies in a small number of people.

Broadly neutralising antibodies (bnAbs) are antibodies that can recognise and neutralise multiple strains of HIV. They have been seen as a potential key to an HIV vaccine but have been difficult to generate in humans.The research has been published in Cell.

The new vaccine candidate, DHVI, was tested in a small clinical trial. The trial showed that the vaccine was able to generate bnAbs in several people after two doses.

This is promising news for the development of an HIV vaccine. However, more research is needed to confirm these results and to determine the safety and efficacy of the vaccine.

"This work is a major step forward as it shows the feasibility of inducing antibodies with immunisations that neutralise the most difficult strains of HIV," said senior author Barton F Haynes, MD, director of the Duke Human Vaccine Institute (DHVI). "Our next steps are to induce more potent neutralising antibodies against other sites on HIV to prevent virus escape. We are not there yet, but the way forward is now much clearer."

In a phase 1 trial of an HIV vaccine, 20 healthy participants were tested. Fifteen received two doses, and five received three doses. The vaccine showed strong immune responses, with a 95% serum response rate and a 100% CD4+ T-cell response rate after two doses. It also induced broadly neutralising antibodies. The trial was stopped after one participant had a non-life-threatening allergic reaction, likely due to an additive.

"To get a broadly neutralising antibody, a series of events needs to happen, and it typically takes several years post-infection," said lead author Wilton Williams, Ph.D., associate professor in Duke's Department of Surgery and member of DHVI. "The challenge has always been to recreate the necessary events in a shorter space of time using a vaccine. It was very exciting to see that, with this vaccine molecule, we could actually get neutralising antibodies to emerge within weeks."