Short-term measures of relative efficacy predict longer-term reductions in human immunodeficiency virus type 1 RNA levels following nelfinavir monotherapy.

We calculated the relative efficacy of treatment, defined as the rate of decline of virus levels in plasma during treatment relative to the rate of decline during highly potent combination therapy, in human immunodeficiency virus type 1 (HIV-1) patients treated for 56 days with different doses of the protease inhibitor nelfinavir. Relative efficacies based on the rate of decline of HIV-1 RNA levels in plasma over the first 14 to 21 days correlated with drug dose and viral load reduction by day 56. Calculation of relative treatment efficacies over the first 2 to 3 weeks of treatment can allow rapid assessment of new antiretroviral agents and dosing regimens, reducing the need to keep subjects in clinical trials on monotherapy for prolonged periods of time.

Decay characteristics of HIV-1-infected compartments during combination therapy.

Analysis of changes in viral load after initiation of treatment with potent antiretroviral agents has provided substantial insight into the dynamics of human immunodeficiency virus type 1 (HIV-1). The concentration of HIV-1 in plasma drops by approximately 99% in the first two weeks of treatment owing to the rapid elimination of free virus with a half-life (t1/2) of < or =6 hours and loss of productively infected cells with a t1/2 of 1.6 days.

Modeling HIV infection of CD4+ T-cell subpopulations.

We develop and analyze a set of models for the interaction of HIV with CD4+ T cells. We consider three major subpopulations of T cells: virgin, activated and memory. In our first model we assume that HIV can infect activated cells but not resting cells.