Impact of Combined Therapy in HIV-1 Treatment: A Double Impulsive Approach

The major class of antiretroviral drugs used in the treatment of HIV positive patients are fusion inhibitors (FIs) and protease inhibitors (PIs). The fusion inhibitor enfuvirtide is effective in early viral life cycle and prevents viral entry into host cells. Protease inhibitors efficiently reduce the number of infectious virus particles. In this article, a mathematical model has been derived to study the effect of enfuvirtide in combination with protease inhibitors in HIV treatment. The dynamics of the two drugs have been analysed with a double impulsive control approach. We have considered different impulse interval for each drug and determine the threshold value for the dosages and dosing intervals to ensure the stability of disease free equilibrium. This study suggests that FIs-and-PIs combination therapy can have a better outcome than single drug activity; furthermore it can also be a better treatment strategy than the current combination of drugs when applied with proper dose and dosing intervals.