AIDS Vaccine Advocacy Coalition Voices Disappointment In Trial
Main Category: HIV / AIDS News
Article Date: 22 Sep 2007 - 0:00 PDT

The AIDS Vaccine Advocacy Coalition (AVAC) released the following statement
from Executive Director Mitchell Warren about the announcement that
vaccinations have been discontinued in the STEP Study, a test-of-concept
trial of the MRK-Ad5 AIDS vaccine candidate developed by the Merck Research
Laboratories:

"Today's announcement about the STEP Study is a deep disappointment and a
scientific setback for the AIDS vaccine field. However, it must be seen for
what it is: the failure of a product to show efficacy in a specific trial.
Clinical testing of AIDS vaccines is a scientific process and, while this
is a disappointment, it is in no way the end of the search for an AIDS
vaccine.

"These data are certainly not the ones that we had hoped for. The entire
HIV vaccine field, including AVAC, had been looking to STEP and its
companion Phambili trial in South Africa, to provide initial evidence of
vaccine-related benefits. Even as the data disappoint, we also note the
success of the STEP Study trial design in providing a swift answer to the
critical question of whether or not the vaccine provided any benefits. A
successful clinical trial is one that produces a scientifically accurate
result. It may not be the result you had hoped for, but it answers
questions that help the field move forward.

"We applaud Merck's tremendous leadership on HIV vaccine research. The
company has set an example for the field, taking on one of the most
important health technology challenges of our time. Merck and its
collaborator, the US NIH-funded HIV Vaccine Trials Network, have been
committed, strategic and willing to take risks at every stage of evaluating
MRK-Ad5, and they must be commended for this. AVAC also recognizes the
contributions of the thousands of volunteers in these trials. Their
altruistic involvement makes HIV vaccine research possible. It is essential
to build on what has been learned here and proceed with further research as
rapidly as possible. Millions of lives are at stake.

"In the next weeks and months the AIDS vaccine field will need to make
carefully-considered decisions about whether to move forward with planned
trials of related vaccine strategies, and how to proceed with the Phambili
trial, which has paused immunizations and enrollment. AVAC is committed to
working with many other stakeholders in the AIDS vaccine field and in other
areas of AIDS prevention research to ensure that these discussions are
thoughtful, transparent, and clearly communicated to global audiences.

"These results do not change our fundamental view. Developing an AIDS
vaccine will require a series of large-scale human trials in many different
countries over a number of years. These trials need to be designed to
produce clear results and to design better candidates in the future. This
research must be complemented by ongoing studies of other new biomedical
prevention strategies, and by full-scale, fully funded implementation of
proven prevention and treatment strategies."

About the STEP Study

An interim analysis of data from the study, involving over 3,000 people
testing an adenovirus-based vaccine (MRK-Ad5) developed by the Merck
Research Laboratories, showed no efficacy in protecting against new
infections or in reducing viral load in people who received the vaccine and
went on to become infected. The study was scheduled to end in 2009.
Periodic reviews of data by an independent monitoring board are part of the
clinical trials process, and the study was halted on the recommendation of
the STEP Study monitoring board after a regularly-scheduled review.

There have been two previous efficacy trials of an AIDS vaccine candidate,
called AIDSVAX. Both of these studies took more than five years from launch
to announcement of the finding -- that the candidate did not protect
against infection. The STEP Study enrolled its first participant in
December 2004, and we have a definitive answer less than three years later.
Getting swift, precise answers about candidates is crucial for the field.
In this sense, the STEP Study fulfilled its purpose-as disappointing as the
results may be.

One reason for this efficiency is that both STEP and its companion trial
Phambili, which tested the candidate in South Africa, were designed as
"test- of-concept" trials, to give an initial answer about vaccine benefits
in a relatively abbreviated timeframe. The STEP Study met its enrollment
targets and its endpoint goals within the timeframe specified by the trial
planners.

About AVAC

Founded in 1995, the AIDS Vaccine Advocacy Coalition (AVAC) is a non-
profit, community- and consumer-based organization that uses public
education, policy analysis, advocacy and community mobilization to
accelerate the ethical development and global delivery of AIDS vaccines and
other HIV prevention options. To help assure its independence, AVAC does
not accept funding from government or pharmaceutical industry sources. For
more information, visit http://www.avac.org.

AIDS Vaccine Advocacy Coalition
http://www.avac.org

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