The purpose of this non-interventional study is a description of use of darunavir in daily practice, in retrospective and perspective manner. Darunavir will be prescribed in the usual manner and in accordance with the terms of marketing authorization. The assignment of a patient to a particular therapeutic strategy will not be decided in advance by this study protocol but instead, it will be part of the current clinical practice. The prescription of the medicinal product will be clearly separated from the decision to include the patient in the study. No additional diagnostic or monitoring procedures will be applied to the patients, and epidemiological methods will be used for the analysis of collected data. After having agreed with the patient on starting treatment with darunavir, and provided that all inclusion and exclusion criteria apply, the physician will document the patient's data. Patients will be observed for at least 48 weeks from baseline visit except for those who withdraw from the study earlier. Patients data will be collected at approximately 0, 1, 3 and 6 months after starting treatment and subsequently every 3 months in accordance with routine practice. The expected number of patients to enroll is about 900. The patients will be treated with darunavir according to the Italian label. The patient must be withdrawn from the study if the treatment with darunavir has been stopped. A last evaluation must be documented when possible, and a resistance test will be collected if available for patients discontinuing for virologic failure. At the end of study visit, information on therapy given after darunavir discontinuation will be collected. For patients discontinuing for virologic failure, data will be collected until the end of the present study, and at least two consecutive measurements of viral load after starting new antiretroviral therapy will be collected, if available. All data collected must be the result of the normal medical care of the patient. The patient's baseline data will be collected within the first week before darunavir administration (at Visit 1). For patients already in treatment with darunavir, baseline and follow up data will be collected retrospectively and prospectively. Further data collection will occur approximately at 1, 3, and 6 months and subsequently about every 3 months according to routine practice, after initiating darunavir treatment.

The patient's baseline data will be collected within the first week before darunavir administration, Visit 1. For patients already in treatment with darunavir, outside the Early Access Program, baseline and follow-up data will be collected retrospectively and prospectively. For patients switched to commercial darunavir from the Early Access Program and already in treatment with darunavir, Baseline Visit data will be collected from the Early Access Program Baseline Visit. For patients already in treatment with darunavir outside the Early Access Program, baseline data will be collected retrospectively starting from the first darunavir intake. For all patients, laboratory examination results collected within 6 months before darunavir treatment starts will be considered as baseline data. For patients switched to commercial darunavir from the Early Access Program and already in treatment with darunavir, Visit 2 won't be performed. For patients starting commercial darunavir or already in treatment with commercial darunavir outside the Early Access Program, laboratory exams related to follow-up visits, Visit 2 onward, can be performed within a time window of one month before or after the corresponding visit date. Further data collection will occur approximately at 1, 3, and 6 months and subsequently about every 3 months according to routine practice, after initiating darunavir treatment. If a patient stops treatment with darunavir at any time, the end of study visit should be performed as soon as possible. Darunavir film-coated tablet, orally administered. Orange, oval-shaped tablet, debossed with 400MG or 600MG or 300MG on one side and TMC on the other side. Duration of observation minimum 48 weeks.

Inclusion Criteria:

- Eligible for inclusion in this non-interventional study are adult patients in need of treatment with darunavir according to Italian label or already in treatment

• Having provided a signed and dated Informed Consent Form

Exclusion Criteria:

• A known hypersensitivity to darunavir or to any of its excipients
• Severe hepatic impairment described as Child-Pugh class C
• Pregnancy or lactation
• Patient previously treated with darunavir that was discontinued for any reason

Patient using darunavir and ritonavir in clinical practice according to label in Italy. Both naive and experienced patients are allowed to enter the study