Nationwide, researchers found 63 "disease progression events" -- including AIDS-related illnesses and deaths among patients receiving a combination of ZDV and 3TC, Eron said. Among patients receiving those two drugs and indinavir, they found only 33 such events.
"There were 18 deaths in the double-therapy arm of the study vs. eight deaths in the triple- therapy arm," he said. "No major differences were found in either safety or toxicity between the two treatments, and study medications were well-tolerated."
Indinavir, a protease inhibitor, works by preventing protease enzymes from cutting up proteins needed to form viruses, Eron explained. The envelope, or outer coating, of the virus still develops, but the core cannot, and therefore the resulting virus is not infectious.
Drugs such as ZDV and 3TC work by inhibiting an enzyme called reverse transcriptase. That enzyme enables the virus' genetic material, or RNA, to convert human genetic material known as DNA into more virus.
The Food and Drug Administration approved use of the combined ZDV and 3TC in November 1995, in part because of a national study Eron led and published in the New England Journal of Medicine. Indinavir has been approved for about a year.
"The people who should be thanked and congratulated for this study and others like it are the people who participated in the trials," Eron said. "They not only have done something that will improve their own care, but they have volunteered to do something that will clearly improve the care of many patients afterwards.
"Treatment with the triple-drug therapy is not easy because of the large number of pills patients have to take and the commitment they have to make to stick to the therapy," he said. "They are the real heroes here."