Early-stage clinical trials have demonstrated the potential of a novel HIV vaccine candidate, which has produced broadly neutralizing antibodies in a small number of participants.
Antibodies known as broadly neutralising antibodies (bnAbs) have the ability to identify and neutralise a variety of HIV strains. Though they have proven challenging to produce in humans, they have been considered as a potential component of an HIV vaccine.The study was released in the journal Cell.
A small clinical trial was conducted to test DHVI, the novel vaccine candidate. The trial demonstrated that after two doses, the vaccine could produce bnAbs in a number of participants.
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.”
