Vacc-4x is a peptide-based HIV therapeutic vaccine. The primary objective of Vacc-4x therapeutic vaccine is to strengthen the immune system's response to HIV p24. ART dramatically reduces the level of virus in circulation in the body, thereby allowing the immune system to focus on the therapeutic vaccine that is administered. ART also allows for the generation of new naïve CD4 cells that can be triggered by the therapeutic vaccine to generate new immune responses to HIV-1. Subjects are therefore immunized with Vacc-4x in the presence of ART to generate new HIV-specific immune responses that can sustain immunological fitness for prolonged periods when patients are removed from ART. It is likely that periodic boosting on ART will be required to sustain the immunotherapeutic effect - in this way ART may become an intermittent therapy.