I et bestemt in vitro resistensforsøg blev der efter 9 måneder isoleret tHIV- 1isolat, som var 87 gange resistent over for tipranavir, hvor det indeholdt 10 mutationer i proteasen:
In one particular in vitro resistance experiment, an HIV-1 isolate that was 87-fold resistant to tipranavir was selected after 9 months, and contained 10 mutations in the protease: