Aids Sufferers’ Latest Hope May Reach Market Soon Ritonavir, Crixivan Slow Virus With Fewer Side-Effects

A new line of potent AIDS drugs is expected to reach the market within weeks.

An advisory committee of the Food and Drug Administration recommended Thursday that the drug Ritonavir, developed by Abbott Laboratories, be made immediately available to seriously ill AIDS patients.

The committee also recommended that the drug by more widely available once the company had conducted new studies. The committee is expected to approve another AIDS drug, Crixivan, developed by Merck & Co., on Friday.

The FDA usually follows the advice of the committee. “It’s possible approval may be lightning fast,” said ommissioner David Kessler. “It’s possible it may take time to work out the complexities.”

Once the FDA approves Ritonavir, said Doug Petkus, a public relations officer at Abbott, the company would get the drug to market in two weeks.

Ritonavir is among a new class of drugs called protease inhibitors, which are hailed as being the new messiahs in the war against AIDS. Although the drug does not cure AIDS, it promises to keep AIDS patients alive for a long time, especially when combined with drugs already in use.

“We haven’t eliminated the virus from the body,” said Anthony Fauci, director of the National Institute for Allergies and Infectious Disease. “The hope is to get the virus’ replication as low as possible.”

Abbott scientists report that their drug halves the death rate of some AIDS patients, compared with others who are on traditional treatments. It also reduces the infections that afflict AIDS patients by two-thirds. In combination with the earlier types of drugs, scientists said virus levels were undetectable after six months.

The AIDS virus is wily, and scientists say it is almost inevitable the virus will eventually develop ways to get around the drugs. The hope is that the drugs are so good that it will be a long time - possibly many years - before that happens.

The new drugs strike at an enzyme called protease that snips important proteins used to assemble new copies of the virus within cells. The drugs clamp up this snipping action, preventing the virus from replicating.

Ritonavir and Crixivan are much more effective than another protease inhibitor, Saquinavir, developed last year by Hoffman-LaRoche, scientists said. The new drugs are expected to have fewer side-effects than the earlier class of drugs, called reverse transcriptase inhibitors. But because patients will likely take the new drugs in combination with the old ones, toxicity is still going to be a problem.

Neither company has yet set a price for its drugs, but both have promised that the price will be reasonable.

Among the other issues that infected people will have to consider:

When to start treatment with the new drugs: Should people diagnosed HIV-positive start on the drugs immediately or should they wait until their immune systems cannot fight any longer and only then bring on the drugs? Which of the new drugs should patients who are using one or another of the older drugs switch to?

What are the ideal combinations and doses for the drugs, and are there unknown side-effects?