Researchers have determined that commonly prescribed triple-drug combination therapies that use old antiviral drugs are the most effective for suppressing the deadly virus that causes AIDS. The findings have major implications for doctors as they grapple with different drugs to treat HIV infected individuals.  VOA's Jessica Berman reports from Washington.

While there's still no cure for AIDS, and new anti-HIV drugs become available, doctors keep puzzling over which combinations of drugs to prescribe to their patients to halt the progression of the deadly disease.

Sharon Riddler, a professor of medicine at the University of Pittsburgh in Pennsylvania, says there's no consensus over which combinations of antiretroviral drugs work the best.

"And it becomes important as we have better options to really have direct comparison," she noted.

Riddler led a study by an international team of researchers that compared the effectiveness of two, triple-combination therapies to a two-drug combination therapy in suppressing the virus. 

Both three-drug regimens included older drugs approved early on by U.S. drug regulators and are often used around the world.

In a study involving 753 patients in 55 countries, investigators found that both triple-drug combinations and the two-drug combination worked well to suppress the virus and slow progression.

But the three-drug combinations with the older medications performed better than the two-drug cocktail.

Riddler says the most effective three-drug combination included a drug called efavirenz.

"We found that the regimen that I think is the most commonly used regimen now is indeed safe, well-tolerated and effective," she said.  "And I think more effective than the alternative regimens that are available."

While that's good news for people in developed countries who can afford efavirenz, the drug is out of reach for many people in the developing world, because it is too expensive.

Gus Cairns is with the European AIDS Treatment Group, an HIV drug watchdog organization. 

Cairns says nivarapine is the antiviral drug of choice in poorer countries because it is cheap.  But he thinks that should change because efavirenz is more effective at keeping the AIDS virus in check.

"There is some evidence that nivarapine is nearly as effective as efavirenz, but really why not go for the best drug available," he asked.

Cairns thinks the makers of efavirenz should lower the cost as they have with other anti-HIV medications.

The study evaluating the effectiveness of HIV combination therapies was published this week in the New England Journal of Medicine.