A Phase IV, Open-label Single-arm Study Investigating the Pharmacokinetics and Pharmacodynamics of the Antiretroviral Combination of Rilpivirine and Ritonavirboosted Darunavir in Therapy-naive HIV-1 Infected Patients.

For patients who are starting to take antiretroviral medication (to treat HIV) for the first time, there are now a variety of different medicines which may be taken together as a combination in order to form an effective treatment which suppresses the virus for prolonged periods of time. Currently, national guidelines recommend the use of two different drugs of one type (the nucleoside/ nucleotide reverse transcriptase inhibitors, NRTI often known as "nukes") with a third drug from one of two other types (either a nonnucleoside reverse transcriptase inhibitor, known as an NNRTI or "nonnuke", or a protease inhibitor, known as a PI) to form a treatment regime of three active drugs. In the UK and Europe, all PIs are given in combination with a small dose of a second PI, ritonavir, which has the effect of boosting the levels of the active PI in the bloodstream. The investigators know from both research studies and patient experience in clinic that a combination of a ritonavirboosted PI with an NNRTI achieves similar results in suppressing the HIV virus, compared to the use of either a PI or NNRTI with 2 NRTI as described above. In this study, the investigators will observe the combination of two licensed antiretroviral medications, ritonavirboosted darunavir(DRV/r) and rilpivirine (RPV), in suppressing virus when given to patients who are commencing treatment for HIV infection for the first time. Both of these drugs are licensed for treatment of patients with HIV in the UK and Europe, and are currently in standard clinical use. The study will monitor this treatment over the first 48 weeks. The investigators will also examine the levels of both drugs in the bloodstream during the first 4 weeks of starting this regimen, to confirm that they remain at levels which the investigators know to be effective against the virus.