The AIDS Drug Pipeline
March 4, 2002 -- Muscular new anti-HIV drugs promise to kick sand in the face of the world's biggest bully. They can't make the brute leave the beach -- but they just might make it leave people be.
Sixteen of these drugs are approved for treating people infected with the AIDS virus. That's not enough. Why? They simply don't cure HIV. Even powerful combinations of the drug only keep the virus at bay.
This means that the virus is always lying in wait, hoping that a person will miss a few doses a month so that it can make a comeback. And when it does it will have learned new tricks that let it defeat more and more of the treatments. HIV that's resistant to one drug often is resistant to some of the others. Sooner than anyone would like, the lifeline of 16 available drugs starts to unravel.
Help is on the way. Reports at the just-ended annual Retrovirus conference -- the most important U.S. AIDS conference -- offered progress reports on a slate of potent new drugs. A couple of these drugs are nearing FDA approval. Most are in earlier stages of human tests. A few are still on the drawing board.
Among the new drugs are two entirely different classes of drugs, offering hope to people who carry virus resistant to multiple drugs. Others are some of the most powerful anti-HIV agents yet discovered. And still other findings point to once-a-day dosing and ways to reduce side effects for existing drugs.
Keeping HIV Out
They call them entry inhibitors. It's a totally different attack on HIV. The idea is to keep HIV out of cells by throwing a monkey wrench into the virus's cell-snatching machinery. Several new drugs hope to do this. Farthest along is T-20. Approval is expected in early 2003. It's already available on a compassionate-use basis for patients who've used up all other options.
"This is absolutely the next important drug in HIV," Jacob Lalezari, MD, director of San Francisco's Quest Clinical Research, tells WebMD.
Lalezari's team showed that T-20 adds to the anti-HIV effect of an extremely potent combination of already-approved drugs. It's added effect is seen whether or not a person carries HIV resistant to other drugs.
The downside: T-20 has to be taken by injection. This inconvenience means that the drug probably will be saved for people to use only after their first- and second-line anti-HIV drugs fail.
However, T-20 might be a great "morning-after" drug for people recently exposed to the AIDS virus. Current anti-HIV drugs fight the virus only after it's penetrated deep inside the body. T-20 keeps the virus from getting a foothold in the first place.
There are several other entry inhibitors in various stages of development.