AIDS TRIALS FUEL HOPE ABOUT ILLNESS : SOME EXPERTS SEE IT AS TREATABLE DISEASE.

Byline: Lawrence K. Altman The New York Times

New findings reported at an international AIDS conference last week promise to transform AIDS from a usually fatal disease into a chronic one that is treatable, many experts say.

With news rapidly spreading about the landmark studies, which showed that new drug combinations can drive the AIDS virus to undetectable levels in blood, many people infected with the AIDS virus are questioning their treatment and asking practical questions for which their doctors are likely to have few immediate answers.

Experts at the meeting often disagreed with one another about how to manage particular patients.

All that is certain is that an earthquake has rearranged the landscape of AIDS therapy, presumably for the better, although even that is not yet certain.

The experts' enthusiasm is restrained by many caveats, like the short duration of the trials, the small number of patients in them, the practical difficulty of the drug regimen and the enormous cost of the drugs and the accompanying tests.

Still, initial signs indicate that unless the virus acquires resistance to the new drug combinations, infection with the AIDS virus may be on the verge of becoming a manageable disease, but one that will be far harder to manage than, say, diabetes.

An immediate question is whether patients should start on the combination drug therapy as soon as they are infected with HIV, the AIDS virus, or wait until the onset of AIDS, which may not occur for many years.

``We heard no clinical data telling us the best time to start'' treatment, said Dr. Kevin DeCock, an AIDS expert from London. He added that there was also little guidance on the drug combinations to use.

Until a general agreement is reached about which therapies and drug combinations are best, many experts said, doctors will probably tailor therapies to each patient's needs. It is likely that those decisions will be based in part on promotions by drug companies, some of which helped pay for the meeting.

Dr. Scott Hammer of the Deaconess Hospital in Boston told participants that the decision on changing therapy should depend on the patient's response to anti-viral drug therapy and the results of tests used to monitor HIV infection.

Experts acknowledged the importance of the new tests to measure the amount of HIV in the blood, called the viral load, as a crucial guide in monitoring therapy.

Though still controversial, the tests have become as important as the older standard, the blood test to measure the number of CD-4 immune cells, which are particularly vulnerable to HIV. It might not be advisable to switch to a new combination therapy if viral load tests and CD-4 counts show that a patient is doing well.

The promise of the new anti-viral drug combinations underscores the importance of HIV tests. Health officials estimate that 650,000 to 900,000 people in the United States are infected by HIV, but it is not known how many have been tested.

Health officials are also concerned that if patients on combination therapies fail to follow the difficult drug-treatment schedules, the emergence of resistant strains of virus may be encouraged, as has happened with drug-resistant tuberculosis strains.

If individuals develop drug-resistant strains of HIV and transmit them to others, the AIDS problem could worsen in coming years, said David Barr of the Gay Men's Health Crisis.