Raltegravir Added to Stable HAART in HIV-1 Infected Subjects With Viral Suppression and Low CD4 Recovery

This is a Phase 3, randomized, double blinded, placebo-controlled study designed to compare the safety, tolerability, antiviral activity and immunological effect of raltegravir added to a previously stable HAART regimen in the treatment of HIV-1 infected subjects with undetectable viraemia and low CD4 recovery. HYPOTHESIS: Adding raltegravir to a stable HAART in patients with undetectable plasma viral load and low CD4 recovery will result in further viral suppression and therefore higher CD4 recovery.