A new study led by scientists at Beth Israel Deaconess Medical Center (BIDMC) shows that an HIV-1 vaccine regimen, involving a viral vector boosted with a purified envelope protein, provided complete protection in half of the vaccinated non-human primates (NHPs) against a series of six repeated challenges with simian immunodeficiency virus (SIV), a virus similar to HIV that infects NHPs. These findings are published online today in Science.

Based on these pre-clinical data, the HIV-1 version of this vaccine regimen is now being evaluated in an ongoing Phase 1/2a international clinical study sponsored by Crucell Holland B.V., one of the Janssen Pharmaceutical Companies of Johnson & Johnson.

"We previously showed that adenovirus vector-based HIV-1 vaccine candidates offered partial protection against SIV when given alone," said lead author Dan H. Barouch, M.D., Ph.D., director of the Center for Virology and Vaccine Research at BIDMC and professor of medicine at Harvard Medical School. The paper describes two new studies in which investigators evaluated the protective efficacy of an adenovirus serotype 26 (Ad26) vectored vaccine boosted with a purified envelope protein.

The results demonstrate that viral vector priming plus protein boosting resulted in complete protection in half of the vaccinated animals. "This shows improvement over our previous results," said Barouch, who is also a steering committee member of the Ragon Institute of MGH, MIT, and Harvard. "Moreover, protection correlated with the magnitude and polyfunctionality of antibody responses. The data show the potential utility of envelope protein boosting following Ad26 priming."

"Bringing the global HIV epidemic under control requires new tools, bold strategies and collaboration among a number of stakeholders," said Hanneke Schuitemaker, one of the study authors and vice president, Viral Vaccines Discovery and Translational Medicine, Janssen. "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."