The Future of AIDS Drugs: Smart Bombs, but No Magic Bullet
July 8, 2000 -- There's been a quiet revolution among scientists developing new treatments to fight HIV infection. Instead of pinning their hopes on the next blockbuster AIDS drug to come out of the development pipeline, researchers are finding smarter ways to use drugs already available. They're gathering to share their successes -- and failures -- at the 13th International AIDS Conference, which begins Sunday in Durban, South Africa.
Until recently, there was only one treatment strategy: Hit the AIDS virus early and hit it hard. This works for many patients able to manage taking so-called "drug cocktails" containing three or even four different medications. Unlike a normal cocktail, however, these drug combinations can't be taken all at once. They require a person to take very large numbers of pills several times a day, sometimes with food, sometimes with a lot of water, and sometimes on an empty stomach -- and this must be done every day without fail. Even more difficult to manage are the side effects, which often include nausea and diarrhea, and, with troubling frequency, problems with fat metabolism that can cause physical deformities.
All these things are better than allowing the HIV infection to progress to AIDS, of course. But not everybody with HIV infection is ready to make this kind of commitment -- and not everybody is able to maintain complex pill-taking schedules, rigid meal times, and unpleasant side effects. No matter how powerful an AIDS drug may be, it won't work if patients can't take it. This hard fact is leading researchers to the conclusion that simpler regimens work best -- even if they are less potent than highly complicated regimens.
"Adherence to therapy is the most important thing -- what predicts success is taking the medications," Jeffrey Lennox, MD, principle investigator of the Emory University AIDS Clinical Trials Unit, tells WebMD. "That seems a flippant thing to say, but with anti-HIV drugs, the level of adherence we expect is over 90%. It's very difficult. You can have incredibly potent agents that people have a difficult time taking. The ideal regimen would be easy to tolerate, easy to adhere to, and quite potent. The regimens available to us now are more like this than the ones available in 1996 -- and the ones that will be available to us in four years will be even better."
Doctors are already beginning to give HIV patients so-called "protease-sparing" regimens that omit the powerful class of AIDS drugs known as protease inhibitors. This concept began as a strategy to keep the virus from becoming resistant to these drugs so that when all else failed, a patient would have still have a strong medicine -- the protease inhibitor -- in reserve.
But Lennox warns that this alternative to the standard drug 'cocktail' is not for everyone. And some patients may need the more powerful and diverse drug regimens to control their disease.