This paper presents optimized structured treatment interruption to reduce medication and establish long-term immune response against HIV-infection. Understanding HIV-related immune system control enables better HIV therapy without using full­treatments. Discrete regimen and continuous regimen characteristics are compared. Controllability of HIV-related immune system is analyzed for better understanding of optimal control in HIV therapy. Using optimal control provides more effective therapy than the full treatment without interruption in terms of controllability analysis. Case studies indicates that the proposed therapy induces long-erm non-progression while preserving high CD4 T-helper cell count and low virus load in HIV-infected patients.