<qa>  What is an open-label, parallel group pharmacokinetics trial of tipranThis is an open-label, randomized, parallel group pharmacokinetics trial of tipranavirritonavir TPVRTV, alone or in combination with RTV-boosted saquinavir SQV, amprenavir APV or lopinavir LPV, plus an optimized background regimen, in multiple antiretroviral ARV experienced HIV-1 patients. 