Merck Notifes Study Participants Whether They Received HIV Vaccine

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Leaders of Merck'sexperimental HIV vaccine study on Monday decided to notify all of the trial's3,000 participants whether they were given the vaccine or a placebo, the San Francisco Chronicle reports. Representatives of Merck, NIH and agroup of physicians who enrolled the trial participants decided to unblind thestudy after several days of discussions at an HIV Vaccine Trials Network conference last week in Seattle (Russell, San Francisco Chronicle,11/14).

Merck in September announced that it had ended the Phase II trial, which beganin late 2004 and involved HIV-negative volunteers, after the experimentalvaccine failed to prevent HIV infection in participants or prove effective indelaying the progression of the virus to AIDS. The trial was stopped by theData and Safety Monitoring Board, an independent overseer. Data recentlysuggested that the vaccine was ineffective among some trial participants with apre-existing immunity to a common cold virus and that the vaccine might haveincreased their susceptibility to HIV infection.

Researchers late last month asked trial participants to return to study sitesfor tests and additional follow-up regarding a possible increased risk of HIV. Researchersin South Africawho were testing the same vaccine have told the 801 participants in theseparate trial if they received the vaccine (Kaiser Daily HIV/AIDS Report, 11/12).

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According to the Chronicle, there was a "compelling ethicalcase" to unblind the study in light of the new data; however, unblindingcould "limi[t] the scientific value" of any data gathered, asresearchers continue to observe the participants. There was "lots of opportunityfor discussion among the investigators and the community, and the vast majoritywere in favor of un-blinding" the study, Susan Buchbinder -- director ofHIV Research for the San Francisco Department of PublicHealth and co-chairof the committee that established the protocols for the trial -- said (SanFrancisco Chronicle, 11/14).

"In our deliberations about this, the central point was: 'What's best forthe participant?'" Ann Duerr, an associate director of the HIV VaccineTrials Network at the Fred Hutchinson Cancer ResearchCenter and one ofthe sponsors of the study -- said. Researchers ultimately realized that"this isn't the last trial we'll do," Duerr said, adding that it is"very important that we keep faith with the community."

Mitchell Warren, executive director of the AIDS VaccineAdvocacy Coalition,welcomed the decision, saying, "In many ways unblinding may be a greatmotivator to keep people coming back," he said (Ostrom, Seattle Times, 11/14).

Reprintedwith permission from kaisernetwork.org. You can view the entire Kaiser Daily HIV/AIDS Report, search the archives, and sign upfor email delivery at kaisernetwork.org/email . The Kaiser Daily HIV/AIDS Reportis published for kaisernetwork.org, a free service of The Henry J. KaiserFamily Foundation.

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