AIDS researchers have begun recruiting gay men in various American cities for a new HIV vaccine trial they are hopeful will be more successful than a previous vaccine trial that was abruptly aborted in 2007 for fear it was increasing some participants' risk of contracting the virus.
The new study, known as the HVTN 505 Study, will examine if the new vaccine can decrease the viral load of those people who become infected with HIV. While it may also help prevent HIV infections, researchers will be closely monitoring participants to see if they do become HIV-positive what impact the vaccine may have on the onset of their illness.
"It is designed to find cells already infected and to reduce the amount of virus in people if they do get infected. If we get clues that we can accomplish that, it will be a huge next step in developing a safe and effective vaccine," said Jonathan Fuchs, director of vaccine studies at the San Francisco Department of Public Health. "It may not prevent infection but we hope this vaccine will work and it will reduce the burden of infection."
AIDS researchers received a boost last week when it was disclosed that a vaccine trial of more than 16,000 volunteers in Thailand showed that it did prevent new HIV infections in trial participants. The vaccine in that trial, which combined two previously unsuccessful vaccines, was reported to have cut the risk of becoming HIV-positive by more than 31 percent.
It was the first time since the start of the AIDS epidemic nearly 30 years ago that a vaccine had shown signs of promise. But the Thailand trial was focused on heterosexual transmission, noted the HIV Vaccine Trials Network's Steven Wakefield, so it remains to be seen if that vaccine would work in gay and bisexual men.
"No matter how great it works or doesn't work, what we will learn is about heterosexual populations. We still have to come back to the U.S. and test it in gay men," said Wakefield.
The new vaccine being studied in American gay and bi men differs in several ways from the one administered in the failed Step Study two years ago. The old study tested whether a vaccine using an adenovirus serotype 5 (Ad5) as a carrier of the HIV genes could prevent new infections.
It was halted after researchers discovered that not only did the vaccine not prevent new infections nor lower the viral loads of men who became HIV positive, but also for those men in the study who were uncircumcised and had antibodies to the Ad5 carrier it increased their chances of acquiring HIV after being vaccinated.
For the new study, which will enroll 1,350 sexually active gay and bi men age 18 to 45 in 12 cities, only men who are circumcised and have no antibodies to Ad5 will be allowed to participate. How the new vaccine is administered has also been changed from the Step Study, with the Ad5 carrier in the HVTN 505 Study having more of its genes deleted.
It is also designed to produce T-cells and antibody responses against HIV envelope proteins, which was not part of the Step vaccine. But as with the Step vaccine, it is not possible to become HIV-positive by receiving the HVTN vaccine.
Those given the new vaccine �" roughly half of the study group �" will first receive three injections of a DNA vaccine and then be given one Ad5 booster shot. Each of the shots will contain more pieces of the HIV DNA than the vaccine used in the Step Study, which had used three Ad5 booster shots.
San Francisco researchers are seeking to enroll 120 Bay Area men into the study and will be launching a locally produced campaign on December 1, World AIDS Day, that will feature participants from the Step Study. Bus shelter ads will go up today (October 1) in the various cities.
Ray Middling, 44, was given the placebo in the Step Study and is applying to be part of the new vaccine trial since he is HIV-negative and circumcised. He will also be part of the new ad campaign encouraging people to take part in the new study.
When he won the San Francisco Leather Daddy title in 2008, Middling told the audience about being part of the vaccine trial and encouraged others to do the same.
"I said in my speech that I give my blood not only my time" to volunteer, he said. "If you think you don't have the time to give up an hour once every three months you are being selfish, is the way I look at it."
Middling said his taking part in the studies stems from living through the early days of the AIDS epidemic and not wanting another generation of gay men to experience the same loss.
"Ninety to ninety-eight percent of the people I knew when I came out are gone," said Middling, who owns a hair salon in Benicia. "So many younger kids are coming out now who didn't live through the epidemic of AIDS and see their friends withering away."
Those interested in joining the study can call (415) 554-9068 or visit the Web site www.sfisready.org.