NIAID will not move forward with the PAVE 100 HIV Vaccine Trial

July 17, 2008

After soliciting and considering broad input from the scientific and HIV advocacy communities, the National Institute of Allergy and Infectious Diseases (NIAID), part of the National Institutes of Health (NIH), has determined that it will not conduct the HIV vaccine study known as PAVE 100.

However, NIAID believes the vaccine developed by its Vaccine Research Center (VRC) is scientifically intriguing and sufficiently different from previously tested HIV vaccines to consider testing it in a smaller, more focused clinical study. Therefore, NIAID will entertain a proposal for an alternative study with one specific goal: to determine if the vaccine regimen significantly lowers viral load—the amount of HIV in the blood of vaccinated individuals who may later become infected with HIV.

The original PAVE 100 study, as presented to NIAID's AIDS Research Advisory Committee in January 2007, proposed to test the VRC's HIV vaccine regimen in a trial initially designed to enroll 8,500 volunteers in the United States, South America, the Caribbean and Eastern and Southern Africa. The study was to begin U.S. recruitment in October 2007 but was postponed last fall following the decision to halt immunizations in the STEP HIV vaccine study. That decision was made after it was determined that the vaccine used in the STEP trial, an investigational product developed by Merck & Co. Inc., failed to prevent HIV infection or reduce viral load.

Subsequent analyses of the STEP trial found increased numbers of HIV infections among those volunteers who received the vaccine in comparison to those who received the placebo; the Merck vaccine itself did not cause HIV infection. The highest risk of HIV infection among vaccinees compared with placebo recipients appeared to be among males who were both uncircumcised and had pre-existing neutralizing antibodies to adenovirus type 5 (Ad5), the common cold virus used in the vaccine as a carrier for the HIV genes. Vaccination resulted in no apparent increased risk in men who were circumcised and who lacked pre-existing neutralizing antibodies to Ad5. The VRC vaccine regimen that was to be tested in the PAVE 100 study has two components, one of which includes an Ad5-based carrier, which is administered to boost immune responses that are first stimulated with a DNA vaccine.

Based on the analyses of the STEP study results, PAVE 100 was redesigned and reduced somewhat in its proposed scope, although it remained a scientifically and logistically complex study. The redesigned PAVE 100 study would have involved testing the VRC vaccine in 2,400 U.S.-based, circumcised men who have sex with men and who lack preexisting neutralizing antibodies to Ad5. The redesigned study would have tested the vaccine's effect on viral load, provided additional safety information about the product, and examined in detail immune responses to the vaccine and their impact on viral load.

Based on the available scientific information, NIAID has decided that the VRC vaccine regimen did not warrant a trial of this size and scope and that PAVE 100 will not proceed. However, NIAID will entertain a smaller, more focused clinical trial designed to answer one important question: Does the product have a significant effect on HIV viral load? If such an effect is noted, then additional studies or expansion of the study to carefully examine immunological correlates could be performed. NIAID will consider such an alternative study and will announce its decision at a later time.

Source: National Institute of Allergy and Infectious Diseases

Explore further: HIV vaccine research requires unprecedented path

Related Stories

HIV vaccine research requires unprecedented path

July 12, 2016

The development of an effective vaccine to prevent HIV infections would represent a critical step toward ending the HIV/AIDS pandemic. Thus far, the only large clinical trial for an HIV vaccine to show promise was the RV144 ...

NIAID creates HIV vaccine discovery branch

June 25, 2008

To accelerate the translation of basic discoveries about HIV into advances in vaccine design and evaluation, the National Institute of Allergy and Infectious Diseases (NIAID), part of the National Institutes of Health (NIH), ...

Priming with DNA vaccine makes avian flu vaccine work better

October 3, 2011

The immune response to an H5N1 avian influenza vaccine was greatly enhanced in healthy adults if they were first primed with a DNA vaccine expressing a gene for a key H5N1 protein, researchers say. Their report describes ...

HIV vaccine trial launches in South Africa

February 18, 2015

A clinical trial called HVTN 100 has been launched in South Africa to study an investigational HIV vaccine regimen for safety and the immune responses it generates in study participants. This experimental vaccine regimen ...

Large-scale HIV vaccine trial to launch in South Africa

May 18, 2016

An early-stage HIV vaccine clinical trial in South Africa has determined that an investigational vaccine regimen is safe and generates comparable immune responses to those reported in a landmark 2009 study showing that a ...

A world first: Vaccine helps prevent HIV infection

September 24, 2009

(PhysOrg.com) -- In an encouraging development, an investigational vaccine regimen has been shown to be well-tolerated and to have a modest effect in preventing HIV infection in a clinical trial involving more than 16,000 ...

Recommended for you

How the finch changes its tune

August 3, 2015

Like top musicians, songbirds train from a young age to weed out errors and trim variability from their songs, ultimately becoming consistent and reliable performers. But as with human musicians, even the best are not machines. ...

Cow embryos reveal new type of chromosome chimera

May 27, 2016

I've often wondered what happens between the time an egg is fertilized and the time the ball of cells that it becomes nestles into the uterine lining. It's a period that we know very little about, a black box of developmental ...

Shaving time to test antidotes for nerve agents

February 29, 2016

Imagine you wanted to know how much energy it took to bike up a mountain, but couldn't finish the ride to the peak yourself. So, to get the total energy required, you and a team of friends strap energy meters to your bikes ...

0 comments

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.