Abstract
In March 2003, enfuvirtide was approved in the USA and the European Union for the treatment of patients with HIV infection who have experienced failure or intolerable side effects of treatment with at least one representative of each antiretroviral drug class. Enfuvirtide has a new mode of action: it binds to the viral envelope glycoprotein 41 that is involved in the fusion of the virus to the membrane of the CD4 T cell. In two large phase III studies, 90 mg of enfuvirtide administered twice daily subcutaneously in addition to a background treatment of other antiretroviral drugs, had a significant favourable effect on both the plasma viral load (decrease) and the CD4 counts (increase) compared to the background treatment alone. Disadvantages of treatment with enfuvirtide are its subcutaneous administration (98% of the patients had local adverse reactions) and the high costs involved (1500 euro per patient per month).
