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Biotech / Medical : Biotech News -- Ignore unavailable to you. Want to Upgrade?

To: sim1 who wrote (2290)	2/24/2003 3:56:53 AM
From: sim1	Respond to of 7143

AIDS vaccine flops in large study By Paul Jacobs Mercury News Posted on Mon, Feb. 24, 2003 The world's first large-scale test of an AIDS vaccine has ended in apparent failure after more than 15 years of effort, according to results released late Sunday by the small biotech company that produced the vaccine. The infection rate in volunteers who received a series of at least three injections of the vaccine was only slightly less than the rate in those who got dummy shots or placebos. The small reduction in infection rates -- less than 4 percent -- was statistically insignificant, according to VaxGen of Brisbane, a Genentech spinoff that was formed to develop and test the vaccine. And it fell far short of a 30 percent reduction that VaxGen believed it would need in order to win approval to market the vaccine, which is called AIDSVAX. But in its analysis of the generally gloomy data, company researchers were surprised to find that some groups among participants -- namely blacks, Asians and other non-Hispanic ethnic minorities -- may have shown a more positive response to the vaccine. Overall, among these minority participants, there was 67 percent reduction of HIV infections in those who received the vaccine. But the company concedes that the number of minority participants was relatively small, which could make the results less reliable. ``This is the first time we have specific numbers to suggest that a vaccine has prevented HIV infection in humans,'' said Phillip Berman, VaxGen's senior vice president of research. ``We're not sure yet why certain groups have a better immune response,'' he said. The study was conducted on more than 5,400 volunteers in North America and Europe -- about 5,100 gay men and 300 women who had sexual relations with infected men. Two-thirds of the participants received a series of AIDSVAX injections. One-third formed a comparison group that received only dummy injections. Overall, about 5.7 percent of those getting the vaccine were infected with HIV over the three-year study compared to 5.8 percent of those getting placebos. Participants were given extensive counseling about avoiding risky behavior that can result in HIV infection -- unprotected sex and the use of dirty needles for illicit drugs. Despite warnings about practicing safe sex, some were infected with HIV. As one other participant explained, ``Accidents happen.'' Of the participants, 5,009 completed at least three injections. Among them were only 498 non-Hispanic minorities. Among this subgroup the infection rate among those vaccinated was only 3.7 percent, compared with 9.9 percent in the placebo group. Neither the clinics administering the shots nor the participants knew who was getting the real vaccine. Company scientists were surprised at the findings among minority participants -- findings that were statistically significant. Those same minorities also showed an increase in the level of antibodies capable of blocking the AIDS virus, which is called the human immunodeficiency virus or HIV. Antibodies are the proteins produced by a vaccinated individual's immune system. If the minority-group findings, which showed a connection between antibody production and infection, turn out to be accurate, it could be helpful in producing improved versions of the vaccine in the future. ``If that holds up, that could be a road map,'' said VaxGen spokesman Jim Key. But at least one university scientist familiar with the results remained skeptical, saying that the numbers were so small that, while interesting, they were not conclusive. Other researchers have in the past predicted that the vaccine would likely fail largely because HIV has proved to be such an evasive quarry -- able to hide within an infected individual's white blood cells, eventually destroying that person's ability to fight off disease. VaxGen is completing a second test of a slightly different version of AIDSVAX in Thailand, in 2,500 injection drug abusers. Those results are scheduled for release later this year and could help confirm or refute the drug's effectiveness among minority participants in the earlier trial. Contact Paul Jacobs at pjacobs@sjmercury.com or (530)756-0236.