 According to mathematical models, even a relatively modest reduction of HIV RNA by 0.5 log could delay the need to start combined antiretroviral therapy by about 3.5 years and potentially prolong the symptom-free phase of HIV-infection by nearly 1 year. On a population scale this could lead to substantial savings with regard to drug and clinical costs and on an individual level to an invaluable gain in drug-free and ideally also symptom-free life years. 