Washington - US AIDS experts on Friday said the cancellation
of a promising AIDS vaccine test by a US government medical institute
was not a major setback to research effort.
They were reacting to Thursday's announcement by the National
Institute of Allergy and Infectious Diseases (NIAID) that it was
cancelling a large human trial of a vaccine similar to one tested,
then dropped, in September 2007.
The dropped vaccine had been developed by the private Merck
pharmaceutical company, with some US government funds. NIAID had been
planning to test a similar vaccine on 2,400 volunteers.
The development came just weeks before the August 3-8 biennial
International AIDS Conference in Mexico City, which draws tens of
thousands of people to push for action and learn of latest
developments in prevention and treatment of the devastating disease.
Wayne Koff, director of research and development at the private
New York-based International AIDS Vaccine Initiative (IAVI) who was
not involved in the test project, said that such decisions belong to
'the normal process of product development.'
'Most candidates in pre-clinical development are not going to
succeed,' he said in an interview with Deutsche Presse-Agentur.
'We're still somewhat in the early stages of vaccine development.'
Koff added that the experience gained from such failed attempts
provides 'useful information for the overall field.'
Dr Anthony Fauci, NIAID director who cancelled the test phase of
Partnership for AIDS Vaccine Evaluation (PAVE), said Merck's failed
experience had shown that scientists must go more slowly because so
little was still understood about the HIV virus that causes AIDS, the
New York Times reported Friday.
In September, the New-Jersey-based Merck suspended its trials of a
vaccine called Ad5, which was intended to lower the amount of virus
in the bloodstream.
It took the step after 49 HIV infections occurred in the 3,000
people who received it, while only 33 occurred in people who got the
placebo injections.
The results suggested the vaccine may have inadvertently increased
HIV risk among people who were exposed to blood or semen containing
the virus.
In its announcement Thursday, NIAID said the 'Merck vaccine itself
did not cause HIV infection.'
Rather, the failure appeared to be connected to antibodies among
males to the adenovirus - a common cold virus - that was used as the
platform to deliver three of nine HIV genes into the test subjects'
bodies.
NIAID said it would consider a 'smaller, more focused clinical
trial designed to answer one important question: Does the product
have a significant effect on HIV viral load?'
IAVI, a private nonprofit research organization which supports
basic research into vaccines, supported Fauci for making a 'bold
decision' in line with 'the way good scientific endeavors work.'
IAVI called for smaller studies in the future 'to test for a sign
of promise before proceeding to large efficacy trials.'
'The decision by NIAID does not reflect paralysis in the AIDS
vaccine field, or a lack of direction forward. In fact, it reflects
the opposite. It reflects the dynamic learning that is the scientific
process, that is pharmaceutical product development,' IAVI said in a
statement.
More than a quarter of a century into the AIDS epidemic, 25
million deaths later, and with an estimated 33.2 million people
currently living with HIV/AIDS, it is still not clear exactly how HIV
causes AIDS, but there is no doubt that it does.
It is also known that AIDS is preventable, although more than
6,800 people contract new HIV infections each day. AIDS is treatable,
yet 2.1 million people - more often than not, young adults in prime
earning and parenting years - die each year from the disease.
USA
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