Based on the assumption, that MDC (multi-drug class) HAART with Raltegravir and Maraviroc leads to a mean reduction of at least one 1 log in patients with PHI and assuming a standard deviation of 1 and a 95% confidence interval (0.5-1.5 log) with a width of 1, the sample size is calculated at ≥16 (assumption of normal distribution).