Pharmacokinetics and Safety Study of Tipranavir in Combination With Low Dose Ritonavir in Human Immunodeficiency Virus (HIV)-Infected Children

Inclusion criteria: 1. Males and females between 2 and 18 years of age. 2. A confirmed diagnosis of HIV-1 infection as defined by two positive assays from two different samples taken at least two weeks apart. The two results may be any combination of the following: HIV ribonucleic acid (RNA) detected by reverse transcriptase (RT)-polymerase chain reaction(PCR) or HIV proviral deoxyribonucleic acid (DNA) detected by PCR HIV culture p24 antigen detection Licensed HIV enzyme-linked immunosorbent assay (ELISA) with confirmatory Western blot 3. Viral load \> 1500 RNA copies/mL. 4. Acceptable screening laboratory values indicative of adequate baseline organ function. Laboratory values are considered acceptable if severity is no higher than Grade 1 for all tests defined by the Division of Acquired Immunodeficiency Syndrome (DAIDS) Table for Grading Severity of Pediatric Adverse Experiences (\> 3 months of age) with the following exceptions: Grade 2 gamma-glutamyl transferase Grade 2 cholesterol Grade 2 triglycerides 5. Signed informed consent prior to study participation from the patient or a legal guardian. Active assent must be given by the patient if the child and/or adolescent is capable of understanding the provided study information (this applies to children with the intellectual age of 7 years or greater) 6. In the opinion of the investigator, an ability to take medications and comply with the requirements of the protocol. Exclusion criteria: 1. Female patients of childbearing potential who: have a positive serum pregnancy test at screening are breast feeding are planning on becoming pregnant are not willing to use two methods of contraception to include at least one barrier method (e.g. latex condom plus spermicidal jelly/foam) 2. Active hepatitis B or C disease defined as hepatitis B surface antigen (HBsAg) positivity or hepatitis C (HCV) antibody or RNA positivity with aspartate aminotransferase(AST)/ alanine aminotransferase(ALT) \> Grade 2. 3. Life expectancy \< 12 months. 4. Patients who are unwilling to abstain from ingesting contraindicated medications and substances which may significantly affect plasma levels of the study medications, notably: Grapefruit juice or Seville oranges Herbal preparations containing St. John's Wort or milk thistle Garlic supplements 5. Active substance abuse. 6. Use of investigational medications or vaccines within 28 days before study entry or during the trial. Some expanded access antiretroviral medications may be acceptable, but must be approved by sponsor. 7. Requirement for any therapy for malignancy or immunomodulatory drug (e.g. interferon, cyclosporine, hydroxyurea, interleukin-2) within 28 days of study entry. Replacement intravenous gamma globulin treatment is acceptable. 8. Any active opportunistic infection within 28 days before study entry or other clinically significant findings that may compromise the outcome of the study. 9. Patients with malabsorption, severe chronic diarrhea or vomiting (more than two episodes of moderate or severe intensity, not attributed to medication therapy and lasting more than four days) within 28 days of the study. 10. Evidence or symptoms of encephalopathy or developmental delay that would reduce compliance.