Large U.S. HIV Vaccine Trial, HVTN 505, Halted After Lack of Efficacy Found

April 30, 2013

On April 25, HVTN 505, a large phase-2b HIV vaccine trial, was discontinued by the National Institute of Allergy and Infectious Diseases (NIAID) due to a lack of efficacy for the vaccine regimen being studied.

The trial was stopped after an independent data and safety monitoring board (DSMB) found, during a routine review, that the vaccine candidates did not prevent HIV infection or reduce HIV viral load among participants who had become infected during the study period.

The trial, conducted by the NIAID-funded HIV Vaccine Trials Network (HVTN), began in 2009 and followed 2,504 volunteers from across 19 cities in the U.S. The participants consisted of men who have sex with men (MSM) and transgender persons who have sex with men.

HVTN 505 used a prime-boost approach similar to the one used in RV144, sometimes referred to as the "Thai prime-boost AIDS vaccine trial," which was the first HIV vaccine trial to show that a vaccine regimen offered some level of protection against HIV in humans. In HVTN 505, a DNA-based vaccine was administered to "prime" the immune system, followed by a recombinant vaccine, the "boost," at week 24.

Although 48 people became infected during the study period, it is important to note, "The two investigational vaccines tested in HVTN 505 cannot cause HIV infection because neither contains live or weakened versions of HIV," as the NIAID points out in a statement.

"This trial has provided a clear, swift answer about a specific vaccine strategy. It's not the answer we hoped for, but the search doesn't end here. There are other approaches that must be pursued without delay, and this result will help to focus and guide research efforts," said Mitchell Warren, executive director of AVAC (AIDS Vaccine Advocacy Coalition), in a statement. "Researchers need to unpack the data from this trial to understand more about why this strategy didn't prevent infection," he added.

While no new immunizations will be administered, the researchers will continue to follow study participants to evaluate the data.

Matthew Rose, an advocate and HVTN 505 trial participant, was saddened by the news, but stated, "I remain hopeful in our search for a vaccine, as this trial showed how researchers and communities can work together to recruit under-represented populations that have not been engaged in AIDS vaccine research. The trial offers a model for how research can be more reflective of the communities that carry the highest burden of HIV and could most benefit from an effective vaccine."

[Editor's note: Rose had previously shared his thoughts about being a participant, in an interview with last December.]

For more on basic vaccine science, read's HIV vaccine primer.

Warren Tong is the research editor for and

Follow Warren on Twitter: @WarrenAtTheBody.

Copyright © 2013 Remedy Health Media, LLC. All rights reserved.

This article was provided by TheBodyPRO.


Add Your Comment:
(Please note: Your name and comment will be public, and may even show up in
Internet search results. Be careful when providing personal information! Before
adding your comment, please read's Comment Policy.)

Your Name:

Your Location:

(ex: San Francisco, CA)

Your Comment:

Characters remaining:


The content on this page is free of advertiser influence and was produced by our editorial team. See our content and advertising policies.