Inclusion Criteria:

• Patients with a documented HIV 1 infection
• Body weight from at least 40 kg at screening
• Screening plasma HIV 1 RNA >= 1000 copies/mL
• Parents or legal representative and trial patients (where appropriate, depending on age and local regulation) willing and able to give consent and assent
• General medical condition, in the investigator's opinion, does not interfere with the assessments and the completion of the trial
• Able to swallow DRV tablets (400 mg) and ritonavir capsules (100 mg)

Exclusion Criteria:

• Patients with presence of any currently active conditions included in the listing of WHO (World Health Organisation) Clinical Stage 4
• Any condition (including, but not limited to, alcohol and drug use), which, in the opinion of the investigator, could compromise the subject's safety or adherence to the trial protocol
• Previous or current use of ARVs ( antiretrovirals)
• Primary or acute HIV infection
• Use of any investigational agents within 30 days prior to screening
• Use of disallowed concomitant therapy
• Pregnant or breast-feeding
• Female patient of childbearing potential without use of effective non-hormonal birth control methods or not willing to continue practicing these birth control methods for at least 30 days after the end of the treatment period
• Patients with clinical or laboratory evidence of significantly decreased hepatic function or decompensation (i.e., liver insufficiency), irrespective of liver enzyme levels
• Any active clinically significant disease (e.g., cardiac dysfunction, pancreatitis, acute viral infection) or findings during screening of medical history or physical examination that are expected to compromise the patient's safety or outcome in the trial