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Front-line
AIDS drugs show staying power: study
 Standard
triple-drug treatment for HIV provides long-term protection against
the development of full-blown AIDS, according to a study released
Friday.
But when this front-line therapy fails, HIV-infected people in poorer
nations could find themselves nearly defenceless against AIDS-related
disease, it warned.
Data on 7,916 HIV-infected individuals in Britain who began standard
triple-drug therapy showed that only 167 developed extensive resistance
to all three types of medication, the researchers found.
The risk of such “triple-class” failure at the end of
10 years was estimated at 9.2 percent, according the study, published
in the British medical journal The Lancet.
This is good news all around, the study said, and especially for
the developing world, where second- and third-line drug therapies
-- used when front-line treatments no longer work -- are too expensive
for most HIV patients and are likely to remain so for a long time.
But a team of scientists led by Andrew Phillips of the Royal Free
and University College Medical School added a cautionary note: when
the three-drug cocktail that has begun to hold the worldwide AIDS
epidemic in check did fail, it does so with a vengeance.
Of those patients for whom the trio stopped working, 90 percent
were resistant to seven first-line drugs, and a large proportion
of those -- 58 percent -- failed second-line therapies as well.
“This finding has implications for the treatment of patients
in developing countries,” commented Edward Mills of the British
Columbia Centre for Excellence in HIV/AIDS in Canada, and Jean Nachega
of John Hopkins University in the United States, also in The Lancet.
“In such settings, only one or two regimes are normally available,
which results in disastrous consequences when these regimes fail,”
they said.
The three main classes of front-line HIV antiretroviral drugs --
nucleoside reverse transcriptase inhibitors, non-nucleoside reverse
transcriptase inhibitors, and protease inhibitors -- are judged
to have failed when they lose their ability to suppress the replication
of the HIV virus, which cripples the immune system.
Mills and Nachega also point out that the British patients, compared
to HIV-infected people in poorer nations, typically started therapy
when their immune systems still had a greater capacity to fight
off the virus.
The rate of drug failure was higher for those whose white blood
cell count was low.
More than 33 million people around the world are living with HIV
or AIDS, more than two-thirds of them in sub-Saharan Africa, according
to UNAIDS.
At the end of 2006, more than two million people there were getting
the life-saving trio of pills, a 54-percent increase over the previous
year, according to the World Health Organisation.
Even so, only 10 percent of those in need are currently receiving
treatment.
The UN agency estimates that there will be 2.5 million new infections
in 2007, and that the disease will have claimed 2.1 million lives.
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