An intensification with the HIV-1 integrase inhibitor Raltegravir (RAL) of a stable HAART regimen with persistent HIV-1 viral suppression could increase the slope of decay of the HIV-1 latent reservoir.

While highly active antiretroviral therapy (HAART) reduces plasma HIV-1 levels to below the limits of detection with standard assays, replication-competent virus persist in a stable, latent reservoir in resting CD4+ T cells. So, there is a rapid resumption in plasma viremia when therapy is interrupted.

In addition to cellular reservoir, other pharmacologically privileged areas such as the central nervous system and the genital tract might act as additional sources of residual virus in patients with undetectable levels of plasma HIV-1 RNA. There is great current interest in strategies for depleting and eliminating this reservoir.

The antiviral potency of current regimens emerges as an important determinant of complete viral control. In certain patients, the latent reservoir decay can be hastened with treatment intensification.

An intensification with the HIV-1 integrase inhibitor Raltegravir (RAL) of a stable HAART regimen with persistent HIV-1 viral suppression could increase the slope of decay of the HIV-1 latent reservoir. This could provide further insight into this area, decrease the size of latent reservoir, and translate into clinical benefits for patients being simplified to maintenance monotherapy with RAL or in the HIV-1 rebound kinetics and slope after a programmed treatment interruption.

Inclusion Criteria:

1. HIV-1 infected adults (+18 years old).
2. Complete virological suppression (<50 copies/mL) for += 12 months, including at least 3 times during the last year.
3. Patients on HAART regimen including a PI or an NNRTI and at least two nucleotide inhibitors.
4. Voluntary written informed consent.

Exclusion Criteria:

1. Pregnancy, or fertile women willing to be pregnant.
2. Active substance abuse or major psychiatric disease.
3. Presence of drug-related mutations or any polymorphism or mutation associated to MK-0518 resistance prior to first HAART (only if genotype is available).