Detailed Results from RV 144 HIV Vaccine Trial Published Today in The New England Journal of Medicine and Presented at the AIDS Vaccine 2009 Conference Provide Insight for Future Research
PARIS, Oct. 20 /PRNewswire-USNewswire/ -- Detailed results from
the Prime-Boost HIV Vaccine Clinical Trial involving more than
16,000 adult volunteers in Thailand show that an investigational
HIV vaccine regimen was safe and modestly effective at reducing the
rate of HIV infection compared to placebo. These results were
presented today by the trial collaborators to researchers gathered
at the AIDS Vaccine 2009 Conference in Paris, France and published
online by The New England Journal of Medicine.
"This is the first evidence that a prime-boost HIV vaccine
regimen may prevent infection and represents a significant step
forward for vaccine research," said Colonel Nelson Michael,
Director, Division of Retrovirology, Walter Reed Army Institute of
Research and Director, U.S. Military HIV Research Program (MHRP).
"While it will not likely have any immediate public health benefit,
we are hopeful that the findings will guide additional studies and
accelerate research efforts toward a more effective vaccine."
According to the collaborating partners, the prime-boost
combination of ALVAC HIV and AIDSVAX B/E appeared to lower the rate
of HIV infection by 31.2 percent compared to placebo based on the
modified intent-to-treat (mITT) population (n=51 vs. n=74,
respectively; p=0.04). There was no effect on the amount of virus
in the blood of the study volunteers who received either vaccine or
placebo and subsequently became infected with HIV.
"Experts are interpreting the results and planning additional
studies to maximize the knowledge gained from this study. Our first
step is to see if we are able to determine correlates of
protection," said Colonel Jerome Kim, Deputy Director (Science),
MHRP and the HIV vaccines product manager for the U.S. Army.
"Observations will inform future basic research, non-human primate
and clinical studies to build on the RV144 result."
"All of this together emphasizes the opportunities these trial
results afford - a new vantage point to examine what we understand
about vaccine design, immunogenicity testing and animal models,"
added Colonel Kim. "Further research is required to determine if
immunological mechanisms mediating protection against HIV may be
different from those that control viral replication."
The trial results, first announced by trial collaborators on
September 24, 2009, are based on the mITT population, which is the
most clinically relevant analysis for this proof-of-concept study.
Data from the mITT population, which was monitored by the
independent Data and Safety Monitoring Board during its periodic
review of the study, include all volunteers who entered the study
less seven individuals who were already HIV infected on the first
day of vaccination. "Given that you cannot protect someone from an
infection that they already have acquired, the modified
intent-to-treat analysis excluded these individuals," said
Michael.
The detailed study data, which were embargoed for release before
the AIDS Vaccine 2009 Conference and The New England Journal of
Medicine publication, provide analyses of multiple data subgroups
including ITT and per protocol (PP), their definitions and results.
Data from the PP population show similar trends (26.2 percent
reduction in HIV infection compared to placebo; n=36 vs. n= 50
respectively; p=0.16), though the results did not reach statistical
significance due to the exclusion of nearly one-third of volunteers
from the analysis and the associated loss of statistical power. For
the ITT population, the vaccine regimen reduced infection rates by
26.4 percent compared to placebo (n=56 vs. n=76 respectively;
p=0.08).
The U.S. Army would like to thank the more than 16,000 Thai men
and women who consented to participate in this trial and the
efforts of the Thai Ministry of Public Health. Trial collaborators
include the U.S. Army, the Thai Ministry of Public Health, Mahidol
University, the Armed Forces Research Institute of Medical Sciences
- U.S. and Thai components, the National Institute of Allergy and
Infectious Diseases, part of the National Institutes of Health,
sanofi pasteur, Global Solutions for Infectious Diseases and the
Henry M. Jackson Foundation for the Advancement of Military
Medicine, Inc.
RV144 Trial Background
RV144 tested a prime-boost vaccine strategy that combined two
vaccines based on strains (subtypes) of HIV that circulate in
Thailand. The first, or "prime" vaccine, known as ALVAC HIV, was
developed by sanofi pasteur and the booster vaccine, AIDSVAX B/E,
was originally developed by VaxGen and is now licensed to Global
Solutions for Infectious Diseases.
The proof-of-concept study, which began in 2003, was designed to
evaluate the vaccine strategy's ability to prevent HIV infection,
as well as its ability to reduce the amount of HIV in the blood of
those who became infected after they enrolled in the study.
More than 16,000 HIV-negative men and women between the ages of
18 to 30 years participated in the study; half of these
participants received the prime-boost vaccine regimen and half
received placebo. Volunteers received vaccinations over the course
of six-months and were followed for an additional three-year
period. Before agreeing to participate, all volunteers were
informed of the potential risks associated with receiving the
experimental vaccine regimen used and consented to participate in
the study. Volunteers continued to receive an HIV test every
six-months for three-years following vaccination, in addition to
counseling on how to prevent becoming infected with HIV.
Source: U.S. Military HIV Research Program
CONTACT: Lisa Reilly of MHRP, +1-301-339-3566, lreilly@hivresearch.org;
or Mary Jane Walker of Hill & Knowlton, +1-917-763-6769,
maryjane.walker@hillandknowlton.com,
for U.S. Military HIV Research Program
Web Site: http://www.hivresearch.org/
Posted: October 2009
