PROTEASE INHIBITORS IN DEVELOPMENT

NOTE: Several fact sheets describe drugs that are being tested against HIV: These drugs have not been approved by the Food and Drug Administration (FDA) for use against HIV.
PROTEASE INHIBITORS
These drugs block the protease enzyme. When new viral particles break off from an infected cell, protease cuts long protein strands into the parts needed to assemble a mature virus. When protease is blocked, the new viral particles cannot mature.
PROTEASE INHIBITORS IN DEVELOPMENT
Protease inhibitors being tested in humans include PPL-100. Several firms are trying to develop a new type of protease inhibitor that will not be cross-resistant with existing drugs.

Prezista (Darunavir, TMC114) by Tibotec was approved in June 2006. See Fact Sheet 450.

PPL-100, developed by Ambrilla/Procyon Biopharma, has been bought by Merck. PPL-100 is being studied in Phase II trials.

Tipranavir (Aptivus, PNU-140690) by Boehringer Ingelheim was approved by the FDA in 2005. See fact sheet 449 for more information.

PIs NO LONGER IN DEVELOPMENT
The following drugs are no longer being developed for use against HIV:

Brecanavir (GW640385) by GlaxoSmithKline and Vertex br /> L-756,423 by Merck
Mozenavir (DMP450) by Triangle Pharmaceuticals
RO033-4649 by Roche