The first clinical trial in the Bay Area to test theeffectiveness of an AIDS vaccine was launched this weekthrough a joint project of the San Francisco Department ofPublic Health and the University of California SanFrancisco.
Known as a Phase III trial, the DPH/UCSF study will focus onthe ability of the test vaccine to protect the body againstHIV infection. It is part of a three-year, multi-siteclinical research effort that is the first in the U.S. tolook specifically at this aspect of a test vaccine.
The test vaccine is produced through genetic engineeringtechniques, so it is a synthetic product and does notcontain any live virus. It cannot cause HIV infection.
The test vaccine product, named AIDSVAX, was developed byVaxGen, a biotech company based in Brisbane, Calif. Theoverall trial is being carried out at more than 50 locationsthroughout North America with the goal of enrolling 5,000participants.
The DPH/UCSF team hopes to enroll 300 study volunteers. Study co-directors are Susan Buchbinder, MD, chief of theHIV Research Section at DPH, and James Kahn, MD, associateprofessor in the UCSF Positive Health Program at SanFrancisco General Hospital Medical Center.
The test vaccine is designed to train the immune system todevelop a defense mechanism against the outer covering ofHIV so the virus fails to spread throughout the body. It isnot known if this approach will be effective in protectingthe body against infection. Learning the answer is theoverall objective of the Phase III trial.
In order to take part, volunteers must be adults whocurrently are HIV-negative and at risk for HIV infectionthrough sexual exposure. All volunteers will receiveextensive counseling that will focus on reducing the chanceof becoming exposed to HIV.
The trial is a "double-blind" study with some participantsreceiving the test vaccine and some participants receiving aplacebo, an inactive substance used as a comparison. Neither the volunteers nor the research staff will knowwhich product is being administered. Participants receivethe test vaccine by injection.
The DPH/UCSF researchers emphasize that this trial involvesa test vaccine. They will not enroll anyone whose motive forparticipation is to use the vaccine as a reason to increaserisky exposures by counting on the vaccine to act asprotection against HIV.
"Participating in this trial is one way to make an importantcontribution to HIV vaccine research. But enrolling in thistrial is not a replacement for safe sex," Buchbinderstressed.
Organizing the trial involved careful consideration ofseveral ethical issues, added Kahn.
"The bottom line is that we want all the participants to beas safe as possible--whether they are in the vaccine groupor the placebo group--and for this reason, counseling is anintegral part of the trial," he said. "If participantsfollow some of the risk-reduction advice, it may influencethe outcome of our trial. That is fine with us. The goal isto prevent new infections. We still feel our results will bevalid in learning about the protective nature of a vaccine."
Earlier clinical studies of this vaccine evaluated itsoverall safety, including how it affected the immune systemand whether it caused any adverse reactions in researchvolunteers. Results of these studies, the Phase I and PhaseII trials, showed the vaccine to be safe in humans so far,and ready for evaluation at the next level.
The test vaccine contains two different synthetic versionsof gp120, a protein found on the outer coating of HIV. Thevaccine is designed to stimulate the body to produce whiteblood cells that specifically recognize the gp120 proteinand then produce antibodies to gp120. Vaccine researchershope that these antibodies will be able to recognize andbind to the gp120 protein on the surface of real HIV when itinfects the body, thereby preventing the virus from invadingthe body's immune system and setting up the mechanism ofcontinued HIV infection.
Study participants will undergo a series of seven vaccineinjections over a 30-month period. Blood samples will betaken and other tests conducted at regular intervals. Volunteers can enroll either through DPH or UCSF. Interested persons should call 415/514-4822 for completeinformation.
"It will take a sustained and probably lengthy effort todevelop a vaccine that stops HIV in San Francisco and aroundthe world," said Mitch Katz, MD, director of DPH. "Thistrial is a new and important step in fulfilling thatcommitment."
Thomas Coates, PhD, director of the UCSF AIDS ResearchInstitute, said, "This DPH/UCSF study represents the best inclinical research: using our local research strengthscollaboratively and taking new steps in the path towards apreventive AIDS vaccine."
"We will greatly benefit from the expertise these tworesearch groups bring to this important clinical trial,"said Don Francis, MD, DSc, president of VaxGen. "As a BayArea company, we are pleased to be working with the peopleof San Francisco to test this vaccine."
Both the DPH HIV Research Section and UCSF have been activein HIV vaccine research over the past 7 years.
DPH has a long history of working with people at risk forHIV infection since the 1970s, when it conducted studies ofhepatitis B in San Francisco. This research provided thefoundation for some of the earliest studies of the AIDSepidemic.
A UCSF team at San Francisco General established one of thenation's first HIV/AIDS units 15 years ago. It hasdeveloped into a comprehensive service with extensiveprograms in clinical care and research. Some of the newestprograms focus on people who are at high risk for HIVinfection, such as the Options project and Post-ExposurePrevention project.
In addition to the North American trial, VaxGen plans toenroll a group of 2500 men and women in Bangkok to test theeffectiveness of a version of the vaccine tailored for HIVstrains common in Thailand.
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