Vaccine trial participants warned of increased HIV risk
Posted by pozlife on November 3, 2007
Dr. Mark Mulligan, executive director of the Hope Clinic, stressed that despite concerns, the HIV vaccine could not cause HIV infection. (Photo courtesy the Hope Clinic)
Vaccine trial participants warned of increased HIV risk Gay
Scientists studying ‘around the clock’ to see if infections are related to test
Friday, November 02, 2007
ATLANTA — Some U.S. participants in the recently halted HIV vaccine trial co-sponsored by Merck & Co. are being told by study coordinators they may be at higher risk for contracting HIV if they received the actual vaccine and not the placebo.
Globally, some 3,000 volunteers participated in the HIV vaccine trial, including dozens of gay men in Atlanta who joined the study through Emory University’s Hope Clinic. All volunteers were HIV negative when they began participation.
“We are talking to each and every participant and asking them to assume the worst and act as if they’ve been put at greater risk and to be extra vigilant in being safe,” said Sarah Alexander, spokesperson for the HIV Vaccine Trials Network.
Dr. Mark Mulligan, executive director of the Hope Clinic, said participants have been contacted about possible risks, but noted that the vaccine itself could not give anyone HIV.
“The vaccine itself cannot cause HIV — we must stress that,” he said.
So far,volunteers in the trial appear to be taking the warnings in stride.
“This doesn’t really bother me,” said Randy Reardon, 42, a gay man who volunteered for what is known as the STEP trial two years ago.
“But it may make some people more hesitant [to participate in future HIV vaccine trials] because they may not get all the correct information,” added Reardon, who is studying to be a nurse practitioner at Georgia State University. “Whether it’s the vaccine or behavior, I don’t know. But I’m not worried because my behavior hasn’t changed.”
The first detailed review of the STEP data will occur on Nov. 7 at a special open scientific session of the HIV Vaccine Trial Network in Seattle.
Merck officials did not respond to interview requests by press time.
Phase II of the STEP trial in the U.S., Australia, South America and the Caribbean was halted Sept. 21 after three years of research when it was determined by an independent Data & Safety Monitoring Board that the vaccine did not stave off HIV infection nor reduce the virus in those who became infected.
In an Oct. 23 press release, the National Institute of Allergy & Infectious stated a “sister” trial in South Africa, known as the Phambili study and using the same HIV vaccine, also halted enrollment and immunizations. The institute is part of the National Institutes of Health, which funded the Merck investigational vaccine trial. The South African trial, also in Phase II and begun in February, was stopped because an independent DSMB there also determined the vaccine was not working.
The DSMB in South Africa also recommended volunteers be told whether they received the vaccine or placebo, be strongly encouraged to return to their study sites for protocol-related tests, and be counseled about the possibility “that those who received the vaccine may have an increased susceptibility to acquiring HIV infections,” according to an NIH press release.
A difference in the STEP trial and the Phambili trial, while both used the same HIV vaccine, is that the volunteers for the STEP trial were overwhelmingly gay men while in South Africa most volunteers were heterosexual women.
When vaccinations were stopped in the STEP study in the U.S. and other countries last month, the study leadership for Phambili temporarily halted enrollment and injections there as well, said Alexander, the HIV Vaccine Trials Network spokesperson.
The Phambili DSMB then reviewed the available data from the STEP study, which showed 24 cases of HIV infection among the 741 volunteers who received at least one dose of the investigational vaccine, while 21 cases of HIV infection were seen in the 762 participants who received at least one dose of the placebo.
According to the NIAID, in the subgroup of STEP trial participants who had received at least two vaccinations and who were HIV-negative for at least the first 12 weeks of the trial, the DSMB found 19 cases of HIV infection among the 672 volunteers who received the investigational vaccine and 11 cases of HIV infection among the 691 participants who received the placebo.
At the Phambili DSMB meeting last month, members made the decision to change the temporary halt into a permanent one based on these numbers, Alexander said.
“There have not been any injections in any participants in either of the studies since the announcement Sept. 21,” Alexander explained.
While the STEP study numbers are not statistically significant, “this is a trend we are not comfortable with,” she said.
Volunteers in South Africa are being “unblinded” and told if they received the vaccine or the placebo, as well as being counseled, Alexander said. Plans for unblinding of the STEP study in the U.S. have not been finalized.
“The meeting [on Nov. 7] will include a session on possible ways to address follow up in either a blinded or unblinded fashion, and we will be seeking input from study staff, ethicists, community activists, scientists, etc.,” she said.
But study participants who want to know now can be told if they received the placebo or the actual vaccine, Alexander said.
“Anyone who comes and asks to be unblinded can be unblinded,” she said. “Our No. 1 objective is safety. Volunteers are the most altruistic people.”
She added that for vaccine participants, this is an “unnerving” development and investigators are working “around the clock” to figure out what the data means.
“We’re as confused as you are — we don’t know if this is related to the vaccine or behavior or by chance,” she said. “And the truth is we may not be able to know.”
All participants in the Hope Clinic trial received the necessary three injections while many in the South African trial only received two, according to Mulligan, the clinic’s executive director.
Mulligan, and many others from the Hope Clinic, will be in Seattle next week to get the latest information on the STEP study data. The Hope Clinic also encourages its volunteers to remain blinded for as long as possible as more analysis is completed.
“We’re saying it’s best to stay blinded a little longer because we all want to learn a much as we can,” he said.
Angel Luis Poventud, a gay Atlanta resident, said the letter he received from the Hope Clinic last week informing him of the questions raised in the Phambili trial didn’t cause much concern.
“I would think that if I became HIV positive, it would have to do with more as a result of me rather than the vaccine,” he said.
Poventud added that since he started the trial three years ago, he has had unprotected sex — but he is more careful now about reducing risk in what he calls “well-informed sex.”
“I’m making healthier choices since I entered the trial and learned about reducing risk,” he said. “Prior to the study, I had no fear.”
Poventud is not eager to learn if he received the placebo or the vaccine right now, but would like to know eventually because those who receive the vaccine are not likely to be eligible to volunteer for other HIV vaccine trials. And Poventud wants to do his part to try to find a cure.
“If I’m part of the placebo group, then I will be able to participate in a new trial,” he said.