Early research results are a setback in the quest to vaccinate people
against HIV, the virus that causes AIDS. HIV has killed more than 25
million people worldwide since it was identified in 1981, including 550,000
in the United States.

Chris Swingle
Staff writer

(October 11, 2007) - The only clinical trial in the world investigating
whether an HIV vaccine works in people at high risk for AIDS - including 40
in Rochester - has been halted early.

The Merck vaccine didn't prevent HIV infection or slow the disease in those
who became infected, according to preliminary results of this latest
international study.

This setback in the fight to prevent AIDS may have wider implications. Most
other HIV vaccine studies in the pipeline are taking a similar approach,
which is to prompt the body to produce more of a crucial immune cell called
killer T cells.

"It clearly is a disappointment," Dr. Michael Keefer, director of
University of Rochester Medical Center's HIV vaccine trials unit, said
Wednesday. "Frankly, the Merck vaccine looked as good as anything we had in
the test tube."

The STEP study, also known as the HVTN 502 study, began in December 2004
and included 3,000 adults who were HIV-negative when enrolled but who were
considered at high risk for the infection that causes AIDS. Participants
included both men and women. The UR researchers recruited gay men. The
study took 18 months to be fully enrolled, so it wasn't scheduled to end
until mid-2009.

The study was stopped in late September after the first evaluation of
interim results found that about 3 percent of study participants had
developed HIV, both among those who received the vaccine and among those
who received a placebo, or fake vaccine. Neither the volunteers nor the
researchers knew who received which until the end of the study. Keefer said
he wasn't sure whether any Rochester participants developed HIV.

The early global results found that of 741 volunteers who received the
vaccine, 24 developed HIV. Among 762 volunteers who received a placebo, 21
developed HIV.

HIV spreads through unprotected sex and through shared needles among
injected-drug users. No investigational vaccines can cause HIV infection
because no living or killed virus, or pieces of virus, are used.

All study participants were counseled on how to reduce their risk of
getting HIV and given various supplies, such as condoms. Those who became
HIV-infected during the study were referred for evaluation, medical care
and treatment and offered continued immunological and virological follow-up
for an extended period of time.

At this time, there is no proven cure or vaccine for HIV. There are highly
effective treatments to keep people with HIV healthy longer and to delay
the onset of AIDS, which stands for acquired immune deficiency syndrome.

University of Rochester Medical Center was among 27 STEP study sites in
North America, South America, the Caribbean and Australia. The HVTN 503 or
Phambili study, a trial of the same investigational vaccine among
heterosexual adults, started in January in South Africa and was expected to
be that country's largest with 3,000 participants. It also has been halted.

Earlier this decade, in the first wave of HIV vaccine attempts, researchers
tried to develop an injection that would stimulate antibodies against the
virus. That approach hasn't worked so far.

Keefer said other investigational vaccines show promise. URMC and other
research centers around the world expect to start a new clinical trial in
2008 called PAVE 100 that would involve 9,000 participants at high risk for
HIV.

URMC also is running about a dozen studies of potential HIV vaccines that
showed promise in studies of monkeys. The so-called Phase I studies are
small and test the safety of the vaccines in people. . Vaccines that pass
that test can eventually move to Phase IIB - like the STEP test - to
examine whether the vaccine prevents HIV in high-risk individuals. Positive
results would lead to Phase III trials and, potentially, a licensed
vaccine.

Steven Price, director of prevention services at AIDS Rochester, said
Wednesday, "We're disappointed that the vaccine was not working, but are
encouraged by the tenacity of those doing the difficult work of finding a
vaccine to combat HIV/AIDS. AIDS Rochester will continue to support vaccine
research both locally and globally."

CSWINGLE@DemocratandChronicle.com