Update on antiretroviral therapy of HIV infection.

The in vivo activity of the available anti-HIV compounds has been clearly demonstrated by the results in the treatment of advanced HIV disease and by the reduction of the vertical transmission rate. However, it is also evident that the efficacy of monotherapy is of limited duration, with drug-resistance probably playing a major role. With the new insights into the pathogenesis of HIV-disease suggesting the need for early intervention, and with the evidence that combination regimens are more effective in reducing HIV viral load, the results of large trials that clinically evaluate nucleoside combination regimens as first-line treatments are eagerly awaited. In perspective, protease inhibitors which target a different virus enzyme and that have shown promising results in phase II studies, may also represent a major advance for combination regimens. In fact, the phenomenon of the selection of drug-resistant strains may be overcome by further reducing the HIV replication rate. Hopefully, the continuous progress in basic science and in drug development will ultimately lead to the identification of more efficient therapeutic strategies. However, a global cooperative action to ensure the availability and the accessibility of safe and effective drugs for developing countries should be regarded as one of the future priorities.