NIAID Will Not Move Forward With The Pave 100 HIV Vaccine
Trial
VRC vaccine regimen under consideration for a smaller,
more focused study
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 (see http://www3.niaid.nih.gov/news/newsreleases/2007/step_statement.htm).
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.
An HIV vaccine continues to be our best hope for ending the HIV
pandemic. NIAID is committed to supporting the basic research and
vaccine discovery needed to design promising vaccine candidates
and testing those candidates when appropriate. For information
about clinical HIV vaccine research supported by NIAID, see http://clinicaltrials.gov/ct2/results?term=HIV+vaccine+and+NIAID&recr=Open.
Media inquiries can be directed to the NIAID Office of Communications
at 301-402-1663, niaidnews@niaid.nih.gov.
Press releases, fact sheets and other NIAID-related materials are
available on the NIAID Web site at http://www.niaid.nih.gov.
NIAID is a component of the National Institutes of Health. NIAID
supports basic and applied research to prevent, diagnose and treat
infectious diseases such as HIV/AIDS and other sexually transmitted
infections, influenza, tuberculosis, malaria and illness from potential
agents of bioterrorism. NIAID also supports research on basic immunology,
transplantation and immune-related disorders, including autoimmune
diseases, asthma and allergies.
The National Institutes of Health (NIH) — The Nation's
Medical Research Agency — includes 27 Institutes and
Centers and is a component of the U.S. Department of Health and
Human Services. It is the primary federal agency for conducting
and supporting basic, clinical and translational medical research,
and it investigates the causes, treatments, and cures for both
common and rare diseases. For more information about NIH and
its programs, visit www.nih.gov. |