Aptivus, co-administered with low-dose ritonavir, is indicated for combination antiretroviral treatment of HIV-1 infection in highly pretreated adults and adolescents 12 years of age or older with virus resistant to multiple protease inhibitors. Aptivus should only be used as part of an active combination antiretroviral regimen in patients with no other therapeutic options. This indication is based on the results of two phase-III studies, performed in highly pretreated adult patients (median number of 12 prior antiretroviral agents) with virus resistant to protease inhibitors and of one phase-II study investigating pharmacokinetics, safety and efficacy of Aptivus in mostly treatment-experienced adolescent patients aged 12 to 18 years. In deciding to initiate treatment with Aptivus, co-administered with low dose ritonavir, careful consideration should be given to the treatment history of the individual patient and the patterns of mutations associated with different agents. Genotypic or phenotypic testing (when available) and treatment history should guide the use of Aptivus. Initiation of treatment should take into account the combinations of mutations which may negatively impact the virological response to Aptivus, co-administered with low-dose ritonavir.