Effects of Steady-state TPV/RTV on the Single-dose Pharmacokinetics of Rifabutin and the Effects of Single-dose Rifabutin on the Steady-state Pharmacokinetics of TPV in Healthy Adult Volunteers

Inclusion criteria

• Male and female subjects between 18 and 60 years of age inclusive
• A Body Mass Index (BMI) between 18 and 29 kg/m2
• Signed informed consent prior to trial participation
• Ability to swallow multiple large capsules without difficulty
• Acceptable laboratory values that indicate adequate baseline organ function are required at the time of screening. Laboratory values are considered to be acceptable if severity was less than or equal to Grade 1, based on the AIDS Clinical Trials Group (ACTG) Grading Scale. All abnormal laboratory values greater than Grade 1 are subject to approval by the trial clinical monitor
• Acceptable medical history, physical examination, and 12-lead ECG are required prior to entering the treatment phase of the study. The requirement for chest X-ray is left to the investigator's discretion
• Willingness to abstain from the following starting 14 days prior to any administration of study drug up until the end of the study:

• Grapefruit or grapefruit juice
• Red wine
• Seville oranges
• St. John's Wort or Milk Thistle
• Willingness to abstain from alcohol starting 2 days prior to administration of any study drug up to the end of the study
• Willingness to abstain from the following within 72 hours of pharmacokinetic (PK) sampling:

• Garlic supplements
• Methylxanthine containing drinks (coffee, tea, cola, energy drinks, chocolate, etc.)
• Willingness to abstain from over the counter herbal medications for the duration of the study
• Have been non-smokers for 3 months
• Willingness to abstain from vigorous physical exercise during intensive PK study Days 1, 14, and 15
• Reasonable probability for completion of the study

Exclusion criteria

As a guideline, subjects who have abnormal laboratory values at screening, and who are taking prescription medications are excluded:

• Female subjects with reproductive potential who:

• Have positive serum β-human chorionic gonadotropin at Visit 1, or on study Day 0 or study Day 1
• Have not been using a barrier contraceptive method for at least 3 months prior to Visit 3 (study Day 1)
• Are not willing to use a reliable method of barrier contraception (such as diaphragm with spermicidal cream/jelly or condoms with spermicidal foam), during the trial and 60 days after completion/termination
• Are breast-feeding
• Participation in another trial with an investigational medicine within 60 days prior to study Day 0 (Visit 2)
• Use of any medication listed in Protocol within 30 days prior to study Day 0 (Visit 2)
• Use of any pharmacological contraceptive (including oral, patch or injectable contraceptives) within 1 month prior to study Day 0 and for the duration of the study. Use of Depo-Provera is excluded for six months prior to study Day 0
• Use of hormone replacement therapy within 1 month prior to study Day 0 and for the duration of the study
• Administration of antibiotics within 10 days prior to study Day 0 (Visit 2) or during the trial
• History of acute illness within sixty (60) days of study Day 0. Subjects are excluded if they have an acute illness greater than sixty days prior to study Day 0 if, in the opinion of the investigator, the subject did not qualify as a healthy volunteer
• History of thrombotic disease
• History of migraine headache
• Have serological evidence of hepatitis B or C virus
• Have serological evidence of exposure to HIV
• Recent history of alcohol or substance abuse (within 1 year of screening)
• Blood or plasma donations within 30 days prior to study Day 0 (Visit 2) or during the trial
• Subjects with a seated systolic blood pressure either <100 mm Hg or >150 mm Hg; resting heart rate either <50 beats/min or >90 beats/min. For subjects with a resting heart rate below 50, or above 90, the investigator may discuss their exclusion with the clinical monitor on a case-by-case basis
• Subjects with history of any illness or allergy that, in the opinion of the investigator, might confound the results of the study or pose additional risk in administering TPV, RTV or RFB to the subject
• Subjects who have taken (within 7 days prior to study Day 0) or are taking any over-the-counter or prescription drug that, in the opinion of the investigator in consultation with the clinical monitor, might interfere with either the absorption, distribution or metabolism of the test substances
• Known hypersensitivity to TPV, RTV, RFB, or sulphonamide class of drugs
• Inability to adhere to the protocol
• Cautions or warnings in the RTV and RFB package insert which, in the judgment of the investigator, should exclude a subject