Two studies offer definitive evidence that an AIDS-fighting
triple-drug cocktail suppresses the deadly virus for at least a
year, delaying illness and prolonging life.
The three-drug regimen is far superior to a two- or one-drug
regimen and should be the standard of care for the estimated
650,000 to 900,000 Americans living with HIV, scientists
reported in Thursday's issue of the New England Journal of
If the drugs show sustained effectiveness - as this evidence
suggests - they could change HIV from a death warrant to a
manageable chronic illness in some patients.
It is estimated that fewer than one-third of people living with
HIV in the U.S. are taking the potent combination.
New AIDS treatments have prompted a flurry of Lazarus-like
tales of patients who experienced a near-disappearance of virus
and illness, as well as more cautionary stories of those who
have received little benefit.
But the evidence - both pro and con - had not been put to a
statistically rigorous test.
The two new studies offer some assurance that the effects of
treatment can be both real and sustained, at least in some
The new research also suggests that because the
triple-combination regimen so sharply suppresses growth of HIV,
it may slow or prevent the evolution of resistant viral
strains. This holds out the promise of longer-term effective
The regimen is a potent combination of three antiviral
medications, including the older AIDS drugs AZT and 3TC. It
gets its real kick from the protease inhibitor indinavir,
approved last year.
All three drugs are still, by normal standards of drug
development, experimental. Those taking them are part of
"For the first time, we have definitive data documenting the
effectiveness of this therapy for such a sustained period,"
said Dr. John Mellors of the Veterans Affairs Pittsburgh Health
Care System and a researcher in one study.
One study found triple therapy cut the risk of infections,
cancers and deaths by approximately half, compared to two-drug
Patients getting the triple therapy had a death rate of 1.4
percent over one year, compared to 3.1 percent in patients
getting only two drugs. Of HIV patients on triple therapy, 6
percent progressed to AIDS; of those on two-drug therapy, 11
percent progressed, reported investigator Dr. Scott Hammer of
Harvard Medical School.
The second study looked at patients' blood, rather than general
health, and found that after one year, the triple therapy
suppressed the virus to undetectable levels in 80 percent of
those studied, reported Dr. Roy Gulick and his team from the
New York University School of Medicine.
The triple therapy benefited patients who had previously taken
AZT or those whose immune systems had already been severely
damaged by HIV - two large groups of people that many thought
might be beyond reach.
Used alone or in pairs, without protease inhibitors, the older
drugs AZT and 3TC inhibit the virus but quickly lose their
punch as mutant forms of HIV evolve that are immune to their
The addition of a protease inhibitor, which intercepts the
virus at a different stage in its life cycle, attacks the virus
more completely - and prevents or delays emerging resistance.