- STANFORD, Calif. (www.nando.net) - The AIDS virus has the potential to
outsmart virtually all the drug treatments now approved in the United States
to treat it, according to a study released Sunday.
- "There is a problem with drug resistance,
and we can't fool ourselves," said Stanford University's Dr. Robert
Shafer, lead author of the new research published in the June 1 issue of
Annals of Internal Medicine.
- Shafer's team found that patients previously
treated with multiple drugs to tackle HIV, the virus which causes AIDS,
can develop full resistance to all available medications -- a finding which
could indicate a developing "split" in the AIDS epidemic.
- "There are the newly infected patients,
who have benefited tremendously from powerful new drug combinations that
can effectively shut down viral replication," the researchers said
in a news release.
- "And then there are the patients
with HIV strains resistant to one or more drugs. The potent new drug combinations
may not work in these individuals, for whom new approaches are needed."
- The researchers conducted genetic analyses
of viral samples taken from four patients infected with HIV-1, the most
common U.S. strain of HIV. All of the patients had been on HIV drug treatment
for between four and nine years.
- They also tested 11 different drugs against
the viral samples to determine whether the samples were susceptible to
- All of the patients had initially taken
the drug AZT and then added or substituted new drugs as they appeared,
including the new class of protease inhibitor drugs which have shown promising
results in preventing viral replication.
- Shafer said the study revealed high resistance
to five drugs, including three protease inhibitors, and a lower level of
resistance to three other drugs, known as reverse transcriptase inhibitors.
- "Over the six months, (the viral
samples) were stable, they replicated well, and the (patients') viral loads
remained high," Shafer said.
- He said that although his study focused
on only four patients, he had subsequently genetically sequenced viral
samples from 400 patients in the San Francisco area and found largely similar
- "We have to realize that there is
so much cross-resistance that while there may be 11 approved drugs and
three to four in the (drug development) pipeline, there really aren't 14
or 15 different options," Schafer said.
- "The academic community has to face
that and convince the drug companies of that. Unless we recognize the fact
that certain things aren't going to work, there won't be the incentive
to go back and develop new drugs."