[Entry inhibitors. Ring-free for a new principle of action].

: Entry-inhibitors represent a new option in antiretroviral therapy. They prevent infection of HIV target-cells. According to their mechanism of action they can be divided into three groups: attachment-inhibitors, corezeptor-antagonists and fusion-inhibitors. The fusion-inhibitor T-20 (Enfuvirtide) will be the first substance to be licensed in 2003. It has been shown that entry-inhibition is a realistic goal for clinical use. Until now T-20 was mainly added to an optimized background regimen in intensively pretreated patients. To achieve the best efficacy a combination of substances with only slight preexisting resistance seems to be favorable. Further efforts in providing orally applicable drugs with little potential for developing resistance and with synergistic effects are required.