July 18, 2008
Anthony Fauci, director of NIH's National Institute of Allergy and Infectious Diseases, on Thursday canceled a planned trial of NIH's Vaccine Research Center's HIV vaccine candidate, saying that additional research is needed before the candidate is tested in humans, the New York Times reports.
According to the Times, Fauci's decision to cancel the trial came after several meetings with scientists to discuss a failed Merck vaccine candidate (Altman, New York Times, 7/18). Merck in September 2007 announced it had halted a large-scale clinical trial of its experimental HIV vaccine after the drug failed to prevent HIV infection in participants or prove effective in delaying the progression of the virus to AIDS. The vaccine candidate also might have put some trial participants at an increased risk of HIV.
The VRC candidate, called PAVE-100, is similar to the Merck vaccine in that both stimulate CD4+ T cells against HIV and both contain the cold virus adenovirus-5 (Kaiser Daily HIV/AIDS Report, 3/25). The VRC candidate also contained pieces of HIV strains from around the world to spark immunity (Chase, Wall Street Journal, 7/18).
Despite the trial's cancelation, NIAID in a statement said it "believes the vaccine ... is scientifically intriguing and sufficiently different from previously tested HIV vaccines to consider testing it in a smaller, more focused clinical study." Seth Berkley, president of the International AIDS Vaccine Initiative, said researchers "can still learn something from testing the PAVE candidate in humans" but that it is "not necessary to do so in a trial involving thousands, as called for in the PAVE 100 design" (Fox, Reuters, 7/17).
Fauci emphasized that the agency is "not willing to entirely shelve the concept" of the vaccine but that a "less expensive trial, with less people, that's focused on the question of whether the vaccine can lower viral load" is necessary (Lauerman, Bloomberg/Philadelphia Inquirer, 7/18). "Show me that the vaccine works by lowering the amount of HIV in the blood. Then we will move to a larger trial that will document the link with a particular immune response," Fauci said, adding that until then, a "large trial is not justified" (New York Times, 7/18).
Mitchell Warren, executive director of the AIDS Vaccine Advocacy Coalition, said that researchers "wanted to see the smallest, most-efficient trial to answer the question" of whether it can decrease viral loads and that "PAVE-100 wasn't seen as small or efficient enough" (Bloomberg/Philadelphia Inquirer, 7/18).
Reprinted with permission from kaisernetwork.org. You can view the entire Kaiser Daily HIV/AIDS Report, search the archives, or sign up for email delivery at www.kaisernetwork.org/dailyreports/hiv. The Kaiser Daily HIV/AIDS Report is published for kaisernetwork.org, a free service of the Kaiser Family Foundation, by The Advisory Board Company. © 2008 by The Advisory Board Company and Kaiser Family Foundation. All rights reserved.