Because a higher rate of virological failures in study versus control arm.

Objectives of the study:

1. To verify the safety and the efficacy of the study treatment, defined as the persistent control of the virus' replication at 48 weeks after the simplification to maraviroc + darunavir with ritonavir in patients with R5 tropism by viral DNA genotyping.
2. To collect relevant information about the safety, the immunologic and the economic impact of this strategy.

Inclusion Criteria:

• Patients treated with the same regimen including 3 HAART from at least 4 months
• Aged 18 years or older
• Who gave informed consent to the participation to the study
• With at least two viral load < 50 copies/mL in two consecutive determinations at least 6 months apart (tolerance of two weeks)
• With CD4 cell count > 200 cells/μL and absence of any opportunistic infection or AIDS-related disease for at least one year prior to the screening.
• With R5 tropism by viral DNA genotyping (geno2pheno "clonal")
• With CD4 cell count nadir>50 cell/mmc or 100 cell/mmc if previous enfuvirtide or integrase inhibitors use

Exclusion Criteria:

• With at least one major or two minor mutation conferring resistance to darunavir reported in the update list of International AIDS Society - USA , in previous resistance test
• Previous D/M or X4 viral tropism
• Previous major clinical toxicities (grade >=3) to the proposed drugs of the study
• Pregnancy or breast feeding, desire of pregnancy in the short term
• Past exposure to Chemokine Receptor 5 antagonist
• HBsAg serostatus
• Liver cirrhosis of class C (Child-Pugh)
• Sulpha drug hypersensitivity
• The presence of major non AIDS-defining diseases that, in the opinion of the investigator, may compromise the retention of the patient in the study for the necessary follow-up period.
• Estimated glomerular filtration < 30 ml/min (cockroft-Gaut; MDRD formula if black-African or african-american) at screening visit
• Hypertransaminasemia of grade IV (more than 10 times the upper normal limit) at screening visit