The results of clinical trials of anti-HIV therapy to date have indicated that the goal of maximal viral suppression for the longest possible duration may best be achieved by administering a combination of drugs that inhibit two of the essential enzymes of HIV-1, reverse transcriptase (RT) and protease (PR). The currently used regimens often include a PR inhibitor (PI) in combination with at least two nucleoside analog RT inhibitors (RTIs). Shown in this figure with the NIH Clinical Center are examples of drugs that are used in such a three-pronged attack against HIV: the PI inhibitor Indinavir in the center, flanked by the RTIs zidovudine (AZT) on the left and lamivudine (3TC) on the right. Although the results of this regimen are promising, as are those of a number of other regimens that combine various antiviral drugs, the problem of drug resistance pervades all of these strategies, and no available therapy has been shown to cure HIV. Therefore, a better understanding of the mechanism(s) of drug resistance will be essential for the development of more effective antiretroviral agents and clinical protocols.
Last modified: 14 January 2009
