Experimental HIV Vaccine Provides Complete Protection

Complete protection seen in half of non-human primates vaccinated against repeated challenges with simian immunodeficiency virus.

An experimental HIV vaccine showed promising results during a recent study led by scientists at Beth Israel Deaconess Medical Center.

The novel HIV-1 vaccine regimen involves a viral vector boosted with a purified envelope protein. The treatment was found to provide complete protection in half of the non-human primates (NHP) vaccinated against a series of 6 repeated challenges with simian immunodeficiency virus, which is similar to the HIV that infects NHPs.

The HIV-1 version of the vaccine is currently being evaluated in an ongoing Phase 1/2a international clinical study.

"We previously showed that adenovirus vector-based HIV-1 vaccine candidates offered partial protection against SIV when given alone," lead author Dan H. Barouch, MD, PhD, said in a press release.

A paper published online in Science discusses a pair of new studies evaluating the protective efficacy of an adenovirus serotype 26 (Ad26) vectored vaccine boosted with a purified envelope protein. The researchers found that viral vector priming combined with protein boosting caused complete protection in half of the vaccinated animals.

"This shows improvement over our previous results," Dr. Barouch said. "Moreover, protection correlated with the magnitude and polyfunctionality of antibody responses. The data show the potential utility of envelope protein boosting following Ad26 priming."

The researchers hope the vaccine will eventually provide a powerful tool in stopping the worldwide spread of the virus.

"Bringing the global HIV epidemic under control requires new tools, bold strategies and collaboration among a number of stakeholders," said study co-author Hanneke Schuitemaker. "In line with our company's commitment to address global health needs, we are committed to working with leading experts to develop a preventative HIV vaccine and our team is excited to advance this program into human clinical studies."