Within-host virus models with periodic antiviral therapy.

This paper investigates the effect of drug treatment on the standard within-host virus model, assuming that therapy occurs periodically. It is shown that eradication is possible under these periodic regimens, and we quantitatively characterize successful drugs or drug combinations, both theoretically and numerically. We also consider certain optimization problems, motivated for instance, by the fact that eradication should be achieved at acceptable toxicity levels to the patient. It turns out that these optimization problems can be simplified considerably, and this makes calculations of the optima a fairly straightforward task. All our results will be illustrated on an HIV model by means of numerical examples based on up-to-date knowledge of parameter values in the model.