Important note: Information in this article was accurate in 1998. The state of the art may have changed since the publication date.

Reuters NewMedia, Inc.; Sunday July 5 8:14 AM EDT
Jonathan Birt

Abbott is combining the drug with a small amount of its existing protease inhibitor Ritonavir, which it says greatly enhances the action of ABT-378 and other marketed protease inhibitors (PIs).

Eugene Sun, who is in charge of developing ABT-378, told Reuters in an interview Friday that laboratory tests showed it was around ten times more powerful than existing marketed PIs.

Sun said more powerful drugs were needed to cut the number of pills taken by people with HIV every day. Currently the most successful regimens combine three different drugs and can mean patients swallowing up to two dozen tablets.

PIs are the most potent class of anti-AIDS drug. In combination with another group of drugs, reverse transcriptase inhibitors (RTIs), they have helped save thousands of lives in the United States and Europe over the last two years, dramatically cutting levels of HIV virus in the blood.

"There is nothing magical about the word three. There is a possibility that more potent drugs can result in simpler treatment regimens. The day will come when one drug will be able to replace triple regimens," Sun said.

He said initial Phase II data on ABT-378 involving 32 patients "was very promising but also very preliminary." The drug was used in combination with two RTIs, Bristol Myers Squibb Co's Zerit and Glaxo Wellcome Plc's Epivir.

Main side-effects were mild gastro-intestional problems and headache, but Sun said no patients had dropped out of the trial after six months of therapy. He said it was also good at getting into the blood stream, and unlike some existing drugs did not require a special diet.

Abbott is hopeful ABT-378 will overcome resistance problems seen with other PIs. There is increasing evidence that where the HIV virus learns to resist one PI it becomes resistant to the other three currently on the market, seriously limiting patients' options.

"There is a lot of optimism about this drug for patients that have failed other protease inhibitors," Sun said. "That is based on in vitro (laboratory) data and the next step is to see whether there is action from this drug in people with resistant virus."

A large Phase II study on this aspect of the drug is currently underway, and Abbott hopes to have ABT-378 in late stage, or Phase III trials, by the end of the year. A marketing application, however, is not expected for another two to three years.

Sun is dismissive of moves to look for combinations of drugs that exclude PIs. Three separate regimens which exclude PIs have been presented at the AIDS conference this week, on the grounds that delaying their use will delay build-up of viral resistance.

"Protease inhibitors are responsible for saving lives. Retreating from PIs makes it easier for the virus and that is a retreat from progress over the past two years," he said.

980705
RE980708

Always watch for outdated information. This article first appeared in 1998. This material is designed to support, not replace, the relationship that exists between you and your doctor.

AEGiS presents published material, reprinted with permission and neither endorses nor opposes any material. All information contained on this website, including information relating to health conditions, products, and treatments, is for informational purposes only. It is often presented in summary or aggregate form. It is not meant to be a substitute for the advice provided by your own physician or other medical professionals. Always discuss treatment options with a doctor who specializes in treating HIV.

Copyright ©1980, 1998. AEGiS. All materials appearing on AEGiS are protected by copyright as a collective work or compilation under U.S. copyright and other laws and are the property of AEGiS, or the party credited as the provider of the content. .