Experts criticise US AIDS vaccine trial

[Guest guest]

Leading AIDS experts criticise major US vaccine trial

US scientists and AIDS advocates yesterday called into question the

US National Institutes of Health decision to proceed with trials of a

controversial vaccine strategy in Thailand, saying the $120 million

needed to run the trial would be better spent on newer vaccine

candidates with a better chance of success.

Writing in the journal Science, 22 leading basic scientists and

vaccine researchers called on the US National Institutes of Health to

review whether it is wise to proceed with the study. " 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 write.

The study will use a combination of ALVAC, a canary pox-based vaccine

designed to stimulate CD8+ T-cell responses to HIV, and a booster

using AIDSVAX (a gp120-based vaccine designed to stimulate antibody

responses). However the scientists say that both vaccines have proved

weak or ineffective in studies so far. In particular AIDSVAX has

failed to demonstrate any clear protective effect in two large phase

III studies reported in 2003, and the authors of the letter throw

particular doubt on the claim that a combination of the two vaccines

might somehow stimulate HIV-specific CD4 T-cell responses.

The scientists fear that the study will fail, and warn that the cause

of AIDS vaccine development cannot afford another large and costly

failure.

" The scientific community must do a better job of brining truly

promising vaccine candidates to this stage of development, " said

Professor Lederman of the AIDS Clinical Trials Unit at

Cleveland University Hospitals, " otherwise we risk eroding public

confidence in the research.

One of the leading AIDS advocacy groups in the United States supports

yesterday's letter to Science. " Even if the current trial proceeded

to conclusion and did show some degree of vaccine efficacy, the

design of the study would make it impossible to know whether ALVAC

alone was responsible, or if the addition of AIDSVAX had improved –

or worsened – the outcome " said Jefferys of Treatment Action

Group yesterday. " A second, even larger phase III efficacy trial

would then have to be performed in order to answer this question - a

mind-boggling example of short-sighted planning for which the NIH

should be called to task. "

Further information on website

Development and testing of vaccines - key issues in vaccine

development

http://www.aidsmap.com/treatments/treathitlist.asp?

displaymode=topicid & id=E6AFC1BA-8EF7-4CA3-

HIV vaccines - review of scientific approaches currently being

followed in vaccine development

http://www.aidsmap.com/treatments/treathitlist.asp?

displaymode=topicid & id=E7F7B837-A23C-4F9C-8675-

6581F9CFEBF4 & topicname=HIV+and+AIDS+vaccines & pubid=481E82FD-9628-11D5-

8D08-00508B9ACEB1

http://www.aidsmap.com/news/newsdisplay2.asp?newsId=2503