Maraviroc Immune Recovery Study

Rationale: Improving cellular immunity by means of increasing CD4 cells is one of the goals of antiretroviral therapy in HIV, which is achieved by means of virological suppression. A certain group of patients, the so called "immunologic non responders", fail to reach an acceptable CD4 cell increase despite an adequate virologic response on antiretroviral treatment. Recently a new antiretroviral agent, maraviroc (Celsentry®), is registered for the treatment of patients infected with CCR5 tropic HIV-1 virus. However, data is available suggesting that treatment with maraviroc leads to immune recovery (increase in CD4 cells) in patients who are infected with dual/mixed tropic HIV-1 virus, in the absence of a virologic response. This suggests an alternative mechanism for immune recovery, which could be especially beneficial for this group of patients. Hypothesis: Maraviroc, by a yet unknown mechanism, stimulates immune recovery by increasing CD4+ cell count. Objective: The primary objective is to confirm the hypothesis that maraviroc stimulates immune recovery; the secondary objective is to explore, by virologic and immunologic investigations, the underlying mechanisms of this hypothesis. Study design: multicentre, randomized, placebo-controlled, double blind, exploratory mechanistic study. Study population: HIV-1 infected patients 18 years or older, who meet the inclusion criteria. Intervention: One group receives maraviroc (dose dependent on co-medication), the other group placebo. Main study parameters/endpoints: A 30% increase in CD4 cell rise in the treatment group (compared with placebo). Nature and extent of the burden and risks associated with participation, benefit and group relatedness: 1. In the treatment group subjects will start with a registered antiretroviral agent (maraviroc). 2. During the treatment year patients will perform several study visits, probably three more compared with regular visits on the outpatient clinic. 3. Each visit, blood will