By Randy Dotinga
HealthScoutNews Reporter
Wednesday, April 23

Prospects for an Aids cure loom so far in the future, many scientists won't hazard a prediction. And an effective vaccine is a distant dream, too. But American scientists have made the first major advance in HIV therapy in nearly a decade.  The breakthrough, that offers new hope for Aids patients, is a newly approved drug called Fuzeon that can serve as an alternative therapy for those who have become immune to the most powerful medications.  "This is a huge advance for patients," says Dr Robert Murphy, an Aids expert and professor of infectious diseases at Northwestern University. "It's a very good drug. It will work no matter how resistant patients are to the other drugs."  Could help up to 30 percent of drug-resistant patients.

The US Food and Drug Administration approved Fuzeon - also known as enfuvirtide, or T-20 - in mid-March after an extraordinarily quick review. Its manufacturers, Hoffmann-La Roche Inc. and Trimeris Inc., hope to get the drug to pharmacy shelves by April, which is also National STD Awareness Month.  As many as 30 percent of patients who take Aids drugs may benefit from Fuzeon because their current therapy is no longer effective, Murphy says.  Making Aids more manageable Thanks to powerful medications, Aids has become a much more manageable health threat than it was just a decade ago, at least in Western countries where drugs are affordable and available. 

In the United States, the estimated annual number of Aids-related deaths fell from more than 50 000 in 1995 to fewer than 9000 in 2001, according to federal health statistics.  However, doctors fear the growing trend of resistance to those medications could drive the death toll higher once again.  "The current drugs are working quite well. Patients are going back to work, living longer, and the quality of their life is immensely improved. But we have to realize there's an increasing amount of drug resistance emerging," says Dr Warner Greene, director of the Gladstone Institute of Virology and Immunology at the University of California at San Francisco. 

HIV virus mutates The problem is that the Aids virus, like many germs, can change its form to thwart the killing powers of drugs. Researchers suspect the process accelerates, at least in some cases, when patients forget to take their Aids medications at specific times.  Drug resistance is a fact of life in the Aids world, says Dr Robert Grant, an investigator with the Gladstone Institute.  "There are people in the drug development field who say that if a compound doesn't produce drug resistance, it shouldn't be developed further. It means it's not really inhibiting HIV," Grant says.  Fuzeon attacks HIV in "an entirely new way" Fuzeon, which experts say is the first major advance in Aids drug treatment since the mid-1990s, attacks HIV - the virus that causes Aids - in an entirely new way. And that makes it a valuable alternative to the existing drugs whose power is diminishing, Murphy says.  Unlike all other Aids drugs on the market, which try to disable the virus after it has attacked cells, Fuzeon prevents infection in the first place. That's why it's called an "entry-blocker" or "fusion inhibitor" - it stops the virus from entering or fusing with cells. 

The production barrier blocks out the poor But Fuzeon won't be available to every person who needs it, especially those living in poorer nations.  "The real barrier is its production," says Michael Allerton, HIV policy operations director with the Kaiser Permanente Health Plan of Northern California. "It's extremely hard to produce, and that makes the quantity limited and the price extremely high."  Treatment with Fuzeon is estimated to cost about R160 000 a year, and patients will have to take it with other Aids drugs.  And unlike other Aids medications, Fuzeon does not come in pills. Patients must inject it.  A "devious" virus Murphy says he doesn't expect drug resistance to pose a problem for patients who take Fuzeon, at least for a while, because manufacturers are developing similar medications to supplement it.  And while Fuzeon - like other Aids drugs - can keep the HIV virus at bay, it cannot drive it from the body.  "We are doing much better than we were in terms of chronically controlling the infection, treating it more like diabetes instead of cancer," Greene says. "But I don't think we're close to a cure.

This virus is too devious."  A vaccine is much closer than a cure An Aids vaccine, which would prevent people from getting the disease in the first place, also appears unlikely any time soon. However, experts say a vaccine is much closer than a cure, and several vaccines are in various stages of testing.  In February, researchers released the results of the most extensive study to date of an Aids vaccine. It found the vaccine failed to prevent the disease except among a small sample of blacks and Asians. Critics, who doubt the vaccine works at all, suspect the findings are meaningless.  One Aids expert isn't holding his breath over the prospects for a vaccine.  "To say it's five years off would be optimistic, even if everything goes well with the vaccines we're testing today," says Dr Mark Feinberg, an Aids vaccine researcher and professor of medicine at Emory University in Atlanta.