Eligibility Criteria:
Inclusion Criteria:
* Clinical failure while on the current PI-containing regimen of indinavir, nelfinavir, or amprenavir
* In the investigator's opinion, adherence to the present PI-containing regimen
* Exposure of \>=6 months to the current PI therapy
* Stable PI-containing regimen, i.e., receiving the current two reverse transcriptase inhibitors (RTIs) for at least 2 months prior to study entry
* HIV-1 RNA \>=1000 copies/mL (assayed using the Amplicor polymerase chain reaction (PCR) method at the initial screening visit)
* No limit in CD4+ cell count at the initial screening
* At least two new nucleoside reverse transcriptase inhibitor (NRTI) options available
* Age \>=18 years
* Acceptable screening laboratory test values that indicated adequate baseline organ function at the time of screening. Acceptable laboratory test values consisted of the following: severity \<=Grade 1 (ACTG Grading Scale). Stable Grade 2 abnormalities were permitted if the values had been demonstrated and documented for at least \>=2 months. All laboratory values \>Grade 2 were subject to approval by the P\&U Clinical Program Leader or designated personnel and subsequently by the BI designated personnel
* Acceptable medical history, physical examination, ECG, and chest radiograph prior to entry into the treatment phase of the study
* Use of a barrier contraceptive method of birth control for at least 30 days prior to study drug administration, during the study, and 30 days after study completion
* Ability to swallow numerous tablets and capsules without difficulty
* Ability to understand and provide informed consent. Minors had to have approval of a parent or legal guardian
Exclusion Criteria:
* Treatment with more than one PI-containing regimen
* Clinically significant active or acute (onset within the month previous to study entry) medical problems, including the following: opportunistic infections, e.g., active cryptococcosis, Pneumocystis carinii pneumonia, herpes zoster, histoplasmosis, or cytomegalovirus; nonopportunistic diseases, including but not limited to the following: progressive multifocal leukoencephalopathy, lymphoma, or malignancy requiring systemic therapy
* Prior exposure (\>7 days) to tipranavir, saquinavir, or ritonavir
* History of clinically significant nervous system or muscle diseases, seizure disorder, or psychiatric disorder that might impair adherence to the protocol
* Taking of any known P450 3A enzyme-inducing drugs within 30 days of study entry and including the following: rifabutin, rifampin, carbamazepine, dexamethasone, phenobarbital, phenytoin, sulfadimidine, sulfinpyrazone, or troleandomycin
* Hypersensitivity to tipranavir, saquinavir, or ritonavir
* Use of interferons, interleukins, HIV vaccines, or any active immunizations within 30 days of study entry
* Taking of any investigational medication with the exception of adefovir dipivoxil (Preveon™) within 30 days of study entry
* Pregnancy or lactation (serum β-human chorionic gonadotrophin test had to have been negative within 14 days of study entry)
* Evidence of substance abuse, which in the investigator's opinion could affect adherence to the protocol
* In the investigator's judgment, inability to comply with the protocol requirements for reasons other than those specified