Abbott's AIDS Drug In Phase I/II Studies

Abbott's HIV protease inhibitor ABT-538 has moved into Phase I/II dose-ranging studies, and two complementary studies, one in Europe and Australia and one in the USA, have completed enrollment. Approximately 70 patients are enrolled in each study.

ABT-538 is a follow-up to two previous protease inhibitors, which were dropped from clinical trials because of poor efficacy. Data now suggests that these agents may have been ineffective because of a high propensity for denaturation by serum proteins in vivo. ABT-538 is believed to have an extremely high bioavailability (90% absorption after ingestion), and Abbott claims it has the highest potency of any protease inhibitor described to date. The company is particularly encouraged by the half-life of the compound (three to four hours) which it says is "a major advance for protease inhibitors."

Meantime, Abbott has predicted that it will file three New Drug Applications in 1995, reports the Pink Sheet. The first of these will be for sertindole, a new antipsychotic licensed from Danish company Lundbeck, while the other two are for new indications for Depakote (divalproex sodium) and Biaxin (clarithromycin).