Some scientists question results of recent HIV vaccine clinical trial

Oct 12 2009

Weeks after clinical trial results showed an experimental HIV vaccine offered some potential protection against the virus, "a second analysis of the $105 million study, not disclosed publicly, suggests the results may have been a fluke, according to AIDS scientists who have seen it," the Wall Street Journal reports. "The second analysis, which is considered a vital component of any vaccine study, shows the results weren't statistically significant, these scientists said," suggesting that the "results could have been due to chance and that the vaccine may not be effective."

The data from the second analysis "were available to the researchers on Sept. 24 when they announced the trial results, but they chose not to disclose them, said Jerome Kim, a scientist with the U.S. Army who was involved in the study. ... The incomplete disclosure raises the question of whether the Army, the Thai government and the U.S. National Institutes of Health -- which helped fund the study -- rushed to give a positive spin to what may turn out to be another inconclusive AIDS-vaccine effort," writes the Wall Street Journal (Naik/Schoofs, 10/12).

The journal Science's blog Science Insider last week first reported on researchers' skepticism over how the results of the HIV vaccine trial had been announced, after a few experts were given a closer review of the data "in confidential briefings." A leading HIV/AIDS investigator said, "The press conference was not a scholarly, rigorously honest presentation ... It doesn't meet the standards that have been set for other trials, and it doesn't fully present the borderline results. It's wrong."

"Colonels Nelson Michael and Jerome Kim, researchers with the U.S. Army who helped run the study, strongly objected to the assertion that they gave the data a positive spin," the blog writes. "We needed to get enough information out so we could give the world community a fair glimpse of what we've learned. We tried very carefully to make sure that message was crystal clear," Michael said, noting "in addition to showing select researchers a fuller presentation of the data, a paper under review at the New England Journal of Medicine describes both analyses, and all the findings will be discussed on 20 October at an open AIDS vaccine meeting in Paris" (Cohen, 10/5).

"The debate is over which participants in the study should be counted — all 16,395 Thais who participated at some point or only the ones who got all the doses of the vaccine and stayed in the study for the full time," the New York Times writes. Typically, when drug or vaccine trials are announced both sets of statistics are included in the analysis.

"The researchers said last month that the vaccine seemed to work 31 percent better than a placebo — and there was only a 4 percent chance that that 31 percent difference was simply a fluke," findings that seemed "a promising step … in the long search for a vaccine against AIDS, which has killed more than 25 million people. But others who have seen the research say that a 'per protocol' analysis, that is, how the vaccine worked among the Thais who got all six vaccine shots at the right time and were followed up to the trial's end, would show that the results were not statistically significant."

"Dr. Anthony S. Fauci, director of one of the National Institutes of Health, which financed the trial, agreed that different analyses of the data could show a weaker effect. But he said the one released on Sept. 24, which included every participant in the trial, was 'the gold standard.' Putting several biostatistical analyses in a news release 'would have confused everybody,' Dr. Fauci said, and suggesting that the researchers were engaging in a cover-up is 'absurd'" (McNeil, 10/10).