First Positive AIDS Vaccine Illusory
US Army researchers accused of giving positive spin to a vaccine
trial that was predicted to fail because the strategy is wrong Dr. Mae-Wan Ho
Another AIDS vaccine failure given a
positive spin
A large clinical trial of an AIDS vaccine
carried out by the US Army and its collaborators in Thailand showed that the
vaccine offered protection against HIV infections by about a third. The
announcement, made at press conferences on 24 September 2009, raised hopes that
a positive AIDS vaccine will finally become available.
But since then, two
published accounts have dashed these hopes. Researchers given confidential
briefings on the trial data, revealed that the results were weaker than even
the modest success claimed [1]. In particular, when the results were analyzed
according to protocol – when only those who got all six vaccine shots at the
right time and were followed up to the end of the trial were included - no
statistically significant protection was found.
The public announcement
was based on the result obtained by including every participant in the trial.
Anthony Fauci, director of the National Institute of Allergy and Infectious
Diseases defended the announcement, and rejected the accusation of a cover-up.
As reported by Jon Cohen in Science magazine [2], of
those who had received any doses of the two vaccines used in combination, 51
had infections, compared to the 74 that became infected in the placebo group.
This difference represented an efficacy of 31.2 percent, statistically significant
at 4 percent probability. When only the participants in both groups that had rigorously
followed the protocol were included, the efficacy was reduced to 26 percent,
and the difference between vaccine and placebo groups was not statistically
significant.
Researchers were critical of the way the announcement was
made to the press. One leading HIV/AIDS investigator, who, like others, wished
to remain anonymous, told Cohen [2]:”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
is wrong.”
Two biostatisticians said that the results based on participants
who had all the shots are the more important data, and were puzzled that the
press conference did not include that analysis.
The trial involved RV114, a combination of a modified
canary-pox vaccine from Sanofi Pasteur and an engineered version of a protein
of the AIDS virus, made by a Brisbane biotechnology company VaxGen Inc. The
phase 3 trial is a two-pronged or “prime-boost” approach: Sanofi’s vaccine
“primed’ the body’s immune system to attach HIV, while the drug developed by
VaxGen “boosted the response [3].
Half of the more than 16 000 participants were given the
vaccines in 2006, and half received placebos. All were provided with condoms,
counseling, regular HIV testing and treatment for any sexually transmitted
diseases. Of the 8 197 participants given the vaccine, 51 became infected, while
74 became infected in the 8 198 given the placebo.
One puzzling aspect of the results was that people
who received the vaccine and still got infected did not have lower levels of
the virus than those who got infected in the placebo group. In other words,
immune response against HIV did not prevent the virus from replicating.
The debate will have little practical consequences, however,
because even on the most positive interpretation, the efficacy is too low to be
a serious vaccine candidate [4]. Experts generally agree that vaccines need to
have 70 to 80 percent efficacy to be useful.
A trial that should never have taken place
The Thai vaccine trial itself was controversial from the start, as we
reported in [5] (Unraveling
AIDS, Chapter 11, ISIS publication). Dennis Burton at the Scripps
Institute, La Jolla, California and 17 other scientists signed a letter
published in the Policy Forum of the Science, expressing “concern about
the wisdom” of the phase 3 trial, doubting the efficacy of the vaccine, and
objecting to the approval process which “lacked input from independent
immunologists and virologists, who could have judged whether the trial was
scientifically meritorious.”
The reply from Robert Belshe at St. Louis University School of medicine and 12 others defended the trial, stating that: “Regardless of
the specific vaccine efficacy, the trial will make a substantial contribution
to HIV vaccine research.” In other words, as we pointed out at the time, the
volunteers were being used as guinea pigs, and neither the efficacy, nor indeed
safety is considered an issue.
ISIS has published a string of articles warning against
vaccines containing the gp120 protein from HIV; see for example [6] AIDS-Vaccines Trials Dangerous
(ISISNews 11/12) and [7] AIDS
Vaccines Worse Than Useless? (SiS 19), which is strongly suspected
of increasing autoimmune response in those vaccinated and may compromise their
ability to protect against HIV infection.
Researchers have gained next to nothing from decades of
failure in this main approach to AIDS vaccines. It is simply a mistake that
ought to be been abandoned at least ten years ago in favour of other more
promising developments to prevention and therapy [5].
References
1. “Success
of AIDS vaccine trial is at issue”, Donald G. McNeil, Jr., The New York
Times, 11 October 2009, http://www.nytimes.com/2009/10/11/health/research/11hiv.html
2. “Unrevealed
analysis weakens claim of AIDS vaccine “success””, Jon Cohen, ScienceInsider, 5
October 2009, http://blogs.sciencemag.org/scienceinsider/2009/10/unrevealed-anal.html
3. “AIDS vaccine promising; experts urge caution”, Victoria Colliver, San Francisco
Chronicle, 25 September 2009, http://sfchronicle.us/cgi-bin/article.cgi?f=/c/a/2009/09/24/MNNM19S3NR.DTL
4. “For
first time, AIDS vaccine shows some success”, Donald G. McNeil, Jr., The New
York Times, 25 September 2009, http://www.nytimes.com/2009/09/25/health/research/25aids.html
5. Ho
MW, Burcher S, Gala R and Veljkovic V. Unraveling AIDS, The Independent Science
and Promising alternative Therapies, Vital Health Publishing, 2005, http://www.i-sis.org.uk/unravelingAIDS.php
6. Ho
MW. AIDS vaccines trials dangerous. ISISNews 11/12, October 2001.
7. Ho
MW. AIDS vaccine worse than useless? Science in Society 19,
26+42, 2003.
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