| Abstract: | Resistance to anti-HIV medications is an ongoing dilemma. A recent study in 16 European countries and Israel found primary drug resistance mutations in 10% of 1,633 people newly diagnosed with HIV disease who had never taken anti-HIV therapy. French clinicians have reported that 78% of viral samples taken between 1997 and 2002 from over 2,000 chronically infected people showed some resistance to at least one antiretroviral drug, and 25% had some resistance to three major drug classes (excluding fusion inhibitors). Similar findings have been reported in the U.S. and Britain. As a significant number of people with HIV find themselves with fewer treatment options, researchers struggle to develop medications that remain effective against genetically varied forms of the virus. Tipranavir, the first in a new category of protease inhibitors (PIs), appears to be such a drug. Studies have shown that tipranavir (formerly known as PNU-140690) durably reduces viral load in some people whose dominant HIV strain is resistant to at least two other PIs. The quality of tipranavir resistance that does develop has also been examined, and the extent of this agent's usefulness in people needing salvage therapy is under investigation. |
