Group of Scientists Questions Value, Cost of Federally Funded AIDS Vaccine Trial in Thailand

A group of 22 prominent AIDS researchers in the Jan. 16 issue of Science magazine question a multimillion-dollar federally funded program to test two AIDS vaccines in Thailand because of the study's high cost and the recent failure of one vaccine in two other large-scale trials, the San Francisco Chronicle reports (Russell, San Francisco Chronicle, 1/16). The study is testing Brisbane, Calif.-based biotechnology company VaxGen's AIDS vaccine AIDSVAX in conjunction with Aventis Pasteur's ALVAC among 16,000 HIV-negative volunteers from Thailand's Rayong and Chon Buri provinces. In the five-year trial, AIDSVAX is used as a booster for the ALVAC vaccine (Kaiser Daily HIV/AIDS Report, 11/13/03). The researchers -- including Dr. Robert Gallo, who co-discovered HIV and heads the Institute for Human Virology in Baltimore; Dr. Ronald Desrosiers of Harvard Medical School; Dr. Douglas Richman of the University of California-San Diego; and Dr. Mike McCune of the Gladstone Institute for Virology and Immunology in San Francisco -- say that the $119 million study should be halted because of the results of two previous VaxGen-sponsored studies, which found that the vaccine was not effective in producing a sufficient immune response, according to the Chronicle (San Francisco Chronicle, 1/16).

Reasoning
According to the researchers, Phase I and Phase II clinical trials have shown that AIDSVAX and ALVAC used separately are ineffective, and there is "no persuasive data to suggest that the combination" of the two vaccines could "induce a better cellular or humoral responses than either component can alone." The scientists write, "We seriously question whether it is sensible now to conduct a third trial that, in our opinion, is no more likely to generate a meaningful level of protection against infection or disease." The scientists conclude, "Society expects the scientific community to develop a vaccine to counter the AIDS pandemic, but there are adverse consequences to conducting large-scale trials of inadequate HIV-1 vaccines" (Burton et al., Science, 1/16). Desrosiers said, "Basically, you have two things that don't work and two things nobody has enthusiasm for, and now you're going to spend $119 million to put them together? We just can't go on testing unpromising products. It wastes limited resources." Mario Stevenson, a co-author and director of the Center for AIDS Research at the University of Massachusetts Medical School, said that the authors also are concerned that if too many vaccines are tested and fail, the citizens and governments of the nations hosting the trials may become wary of scientific studies. "We're really concerned this will create a backlash that will inhibit the ability to get more effective (vaccine) candidates into trials and that will discourage participants from wanting to participate in trials," Stevenson said (Smith, Boston Globe, 1/16). Dennis Burton, a co-author of the Science critique and an AIDS researcher at Scripps Research Institute in La Jolla, Calif., said, "Everything I've seen about the Thai trial suggests that it doesn't have a prayer" (Nesmith, Cox News/Atlanta Journal-Constitution, 1/16).

Reaction
Officials at NIH said that completing the study could hold some benefits, the Boston Globe reports. NIAID Division of AIDS Director of Vaccine Research Peggy Johnston said, "As long as the vaccine is safe and is not going to do any harm to people, what's the harm of doing the trial and getting the data to determine if the vaccine works or doesn't work? There's an urgent need out there for an AIDS vaccine. We can't sit here and debate" (Boston Globe, 1/16). VaxGen spokesperson Kesinee Yip said that a large-scale study "would be a valuable source of new information that could be useful for the field of HIV vaccine research" (Jacobs, San Jose Mercury News, 1/16). "I don't think this is a waste of time," Prasert Thongcharoen, chair of the Thai National AIDS Commission's subcommittee on HIV Vaccine Development, said, noting that Thailand is one of the few countries in which the E-type strain of HIV is present. "Who will do that trial for us if we don't do it?" he asked (Noikorn, Associated Press, 1/16).

Other Groups React
New York-based Treatment Action Group said in a statement, "[I]t would be a far better policy to prioritize the development and testing of these newer and more potent vaccines rather than waste human and financial resources ... on a trial that is extremely unlikely to lead to an effective and licensable AIDS vaccine" (TAG release, 1/15). However, the AIDS Vaccine Advocacy Coalition disagreed, saying, "Cancellation of the trial at this point would send a message to other countries and vaccine developers that the U.S. government has not kept its commitment." Wayne Koff, senior vice president of the International AIDS Vaccine Initiative, said, "Since this really is early in the start of the trial it makes sense to give careful consideration to what the authors are proposing. There may be ways to improve it. People amend clinical trials all the time." NIH officials said in a statement that they "strongly disagree" with the critique authors, adding that they plan to draft a formal rebuttal that they expect will be published in Science (San Francisco Chronicle, 1/16).

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