Potent New AIDS Drug in Pipeline

WASHINGTON, D.C.--Scientists from Abbott Laboratories announced here today that they have begun clinical trials on a new anti-HIV drug that they claim is 10 times more potent than one of the most powerful AIDS drugs now on the market. Test tube studies of the drug, an inhibitor of the protease enzyme that HIV uses to copy itself, suggest that the AIDS virus has an unusually difficult time developing resistance to it.

A battalion of Abbott scientists, who earlier developed a leading protease inhibitor called ritonavir, unveiled their data on ABT-378 at the 4th Conference on Retroviruses and Opportunistic Infections. ''ABT-378 is one of the most potent antivirals we have tested,'' said Abbott's Hing Sham in a presentation this morning. ''Importantly, ABT-378 shows potent inhibition of even highly resistant HIVs.''

Enthused by the early data is David Ho, head of the Aaron Diamond AIDS Research Center in New York City, who worked extensively with Abbott in developing ritonavir. ''This looks good,'' Ho told ScienceNOW. ''It apparently takes care of drug-resistant virus. That's the part that excites me.''

When combined with ritonavir, ABT-378's bioavailability--and thus its effectiveness at killing HIV before resistant strains develop--is greatly increased, Abbott scientists showed in test tube and rat studies. They emphasized that the combination of ritonavir and ABT-378 is more bioavailable than the combination of ritonavir and saquinavir, a protease inhibitor on the market from Hoffmann-La Roche.

A few weeks ago, Abbott launched trials of ABT-378 in 24 people not infected with HIV, said Richard Granneman, Abbott's head of pharmacokinetics. This pilot trial is investigating questions of dose and toxicity. If it passes that hurdle, the next step on ABT-378's arduous path to the market would be a clinical trial to measure its efficacy in infected people.