By DYANA BAGBY
When news came last week that the HIV vaccine trial by Merck & Co. was discontinued because studies showed the vaccine was ineffective, volunteer participant Scott Smith of southwest Atlanta acknowledged disappointment.
“I was bummed. But I knew what the chances were,” he said.
Smith, 39, a volunteer for the vaccine research for just over two years at the Hope Clinic, a subsidiary of Emory University, also said he knew there was a chance the vaccine would fail.
“I wasn’t hysterical because I know there are other vaccines being tested.”
Smith will continue going to his scheduled appointments for however long researchers want to follow participants to find other useful information in the failed trial.
“Every test helps us get closer to a vaccine,” he said.
Smith was one of approximately 130 people taking part in the high-profile HIV vaccine research study at the Hope Clinic.
Globally, some 3,000 volunteers participated in the vaccine research, all of whom were HIV negative when the Phase II clinical trial began. Most volunteers, including those at the Hope Clinic, were gay men because they are at a higher risk of contracting HIV, said Dr. Mark Mulligan, executive director of the Hope Clinic.
The vaccine trial, called STEP and funded by the National Institute of Allergy & Infectious Diseases, part of the U.S. National Institutes of Health, was stopped Sept. 21 after the independent Data Safety Monitoring Board reviewed safety data and and determined the vaccine “did not prevent infection.”
Merck’s was the first major test of a new strategy in HIV vaccine research. The first wave of attempts to develop a vaccine tried to stimulate antibodies against the virus, but that hasn’t worked so far.
The new effort — an approach that is being tried in most other current research — is aimed at making the body produce more of a crucial immune cell called killer T cells. The goal is to simultaneously “train” those cells, like an army, to quickly recognize and destroy the AIDS virus when it enters cells in the bloodstream.
In volunteers who received at least one dose of the three-dose Merck vaccine series, 24 cases of HIV infection were observed in the 741 volunteers who received the vaccine and 21 cases of HIV infection were observed in the 762 participants in the placebo group.
The vaccine also did not reduce the amount of virus in the bloodstream of those who became infected, Merck officials stated.
While not giving an exact number, Dr. Carlos del Rio, who is in charge of the STEP study at the Hope Clinic, said some local volunteers became infected with HIV.
All volunteers were repeatedly counseled about how to reduce their risk of HIV infections, including use of condoms, according to Merck.
Mulligan of the Hope Clinic said he was deeply disappointed in the news but added that vaccine research takes many, many years.
“While disappointment was my main reaction, the next step is, OK, this is science and we’ve gotten a clear and strong answer what direction not to take,” Mulligan added. “We knew it might work, that it might not work. And we learn from that experience, so in that sense, it has been successful. Now we can throw our energy and efforts into other candidate vaccines.”
The STEP study, considered “the lead horse” of HIV vaccine research, “has dropped out of the race,” Mulligan said. “And now the others become more important. The importance of these additional candidates are amplified by this result.”
Del Rio remains optimistic and said the Hope Clinic will participate in future HIV vaccine studies, one set to begin this fall.
Named PAVE 100, this HIV vaccine study will also draw on ways to make “killer T cells,” but will utilize DNA.
“This is not the end,” del Rio said.
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