Hoffmann-LaRoche Inc. on Thursday said it will initiate clinicaldevelopment of an AIDS treatment derived from discoveriesinvolving a compound related to Valium.

The compound, which never made it off the shelf at the Nutley,N.J., company because it lacked enough activity in the brain,provided researchers with a strong lead for treating AIDS.

Roche scientists and their collaborators at the University ofCalifornia, San Diego, and Columbia University reported todayin Science that the benzodiazepine compound inhibitsreplication of HIV at a crucial first step encoded by the TATgene.

TAT inhibitors have been sought because they would notinterfere with processes in cells. The TAT regulator is not foundin cells, and deleting its gene in HIV removes the virus'infectivity.

Known by its code name, Ro5-3335, the Roche compound,added at the time of infection, stopped a spectrum of HIVstrains from replicating inside several cell lines. It was activeagainst HIV-2 strains and against two AZT-resistant viralisolates.

Unfortunately, Ro5-3335 also proved toxic to the kidneys inrats and tinged body tissues yellow due to one of itsmetabolites.

The discovery of the drug's anti-HIV effect, however, led thecompany to the TAT antagonist Ro24-7429, which is currentlyin Phase I safety testing. Roche announced Thursday that it hasstopped searching for a licensing partner and will develop thedrug on its own.

A full clinical development program will be started in 1992,the company said. -- Roberta Friedman, Ph.D.

(c) 1997 American Health Consultants. All rights reserved.