Ultimate goals include developing a once daily combination that avoids irreversibly damaging the immune system and delays disease progression in infected people. Indeed, many candidate drugs are in various stages of the experimental pipeline. Dr. Roy M. Gulick of the Weill Medical College of Cornell University in Manhattan discussed a partial list. TMC-126 and BMS 232632, and others had names like capravirine, tenofovir and tipranavir. Still other candidates are in earlier stages of drug development and have not left the laboratory, have been tested only in animals, or given only to a few individuals for purposes of monitoring safety more than determining effectiveness.
Some experimental drugs are chemically related to members of the three licensed classes.
Other candidates that belong to new classes offer the hope of substantial therapeutic benefits because they disrupt different parts of the HIV cycle left unscathed by the available 15 drugs. One new class inhibits the binding of HIV to a receptor, known as CCR5, situated on a cell surface. A second new class inhibits fusion of HIV to a cell after it gains entry. When and if the Food and Drug Administration will license a 16th anti-HIV drug is unknown. Experience has shown that many promising candidates unexpectedly fall by the wayside during the lengthy series of animal and human tests needed to meet federal licensing requirements.