Combination antiretroviral therapy (ART) for HIV infection has improved the longevity of infected individuals and as new infections occur each year, the overall number in need of ART is rising increasing the financial burden for healthcare services. ART l imitations include increasing multidrug resistance, high cost and the short- and long-term adverse effects of ART (e.g. metabolic toxicity) that need to be addressed in an aging population. Therapeutic vaccination can complement ART and allow for safe pr olonged ART-free periods. Intermittent ART, supported by therapeutic vaccination, has the potential to reduce the financial burden, impact on the development drug resistance, alleviate adverse side effects and improve the quality of life of infected indiv iduals. Vacc-4x is a peptide-based therapeutic vaccine that was found to be safe, well tolerated and immunogenic in earlier clinical development in Norway (phase I & IIa). Vacc-4x, injected intradermally, targets dendritic cells (DCs) in the skin to indu ce cell mediated immunity. Granulocyte macrophage colony stimulating factor (GM-CSF) is also injected because it enhances the activities of the DCs. A large, prospective, randomized, multi-centre, double blind placebo-controlled phase IIB-Test of Concept (TOC) trial of Vacc-4x was successfully initiated in 2008 in the US and Europe. This work was partly supported by a one year grant from the GLOBVAC priority. The principal objective of this project is to complete the phase IIB-TOC trial (enrolling 345 pa tients). The results of this three year project will allow for discussions with the regulatory authorities in the US (FDA) and Europe (EMEA) to determine whether Vacc-4x may enter an early approval process or progress to a phase III clinical trial.