* AIDS gel ineffective in largest trial to date
* Scientists say results disappointing but definitive
* Result adds to setbacks for Endo Pharmaceuticals
(Adds background, details on Gilead's product)
By Kate Kelland
LONDON, Dec 14 U.S. drug company Endo
Pharmaceuticals' (ENDP.O) gel designed to prevent infection with
the AIDS virus was ineffective in trials in Africa, Britain's
Medical Research Council (MRC) said on Monday.
The large international trial of vaginal microbicide Pro 2000
in more than 9,000 women in four African countries found no
evidence that it reduces the risk of HIV infection.
The result is a setback for the specialty drugmaker, whose
shares were hit earlier in the month when U.S. health regulators
declined to approve its Aveed drug for low testosterone.
To date, no such gel, known as a microbicide, has been shown
to prevent HIV infection and this trial "showed conclusively that
Pro 2000 gel was of no added benefit," the council said in a
"This result is disheartening, particularly in light of the
results of a smaller trial sponsored by the U.S. National
Institutes of Health which suggested that Pro 2000 could reduce
the risk of HIV infection by 30 per cent," the council's Sheena
McCormack, who led the trial, said in a statement.
"Nevertheless we know this is an important result and it
shows clearly the need to undertake trials which are large enough
to provide definitive evidence for whether or not a product
The findings also were a setback to researchers trying to
find a microbicide -- a gel or cream that women and perhaps men
can use to protect against the AIDS virus when their partners
cannot or will not use a condom.
Studies presented at an AIDS conference in Canada in February
suggested the Pro 2000 gel, which ENDO acquired through its
purchase of Indevus Pharmaceuticals earlier this year, could cut
transmission rates by a third [ID:nN09513969].
Almost 60 million people have been infected with HIV and 25
million people have died of HIV-related causes since the
beginning of the AIDS epidemic. There is no cure and no vaccine,
although drug cocktails can keep patients healthy.
United Nations data have shown that globally that 33.4
million people had HIV in 2008 and 2 million people died.
The latest trial, which took place between September 2005 and
September 2009, involved 9,385 women and was carried out by the
Microbicides Development Programme (MDP), a not-for-profit
partnership of 16 African and European research institutions.
It found that the risk of HIV infection in women who were
given PRO 2000 to use was not significantly different than in
women supplied with a placebo gel.
Jonathan Weber of the MDP said the result was disappointing
but added: "The trial itself was very well designed and
undertaken, so we know that the results are definitive.
"It is unfortunate that this microbicide is ineffective at
preventing HIV infection but it's still vital for us as
scientists to continue to look for new ways of preventing HIV,"
Weber said in a statement.
Dozens of potential microbicides are being tested, including
a formulation using Gilead Sciences Inc's (GILD.O) HIV drug
Viread, or tenofovir.
(Additional reporting by Ed Cropley in Johannesburg and Maggie
Fox in Washington, editing by Karen Foster and Carol Bishopric)