Optimal Control of a Tumor-Immune System with a Modified Stepanova Cancer Model

In this paper, we investigate strategies for administering chemo- and immunotherapy to force a tumor-immune system to its healthy equilibrium. To solve this problem, we use Pontryagin's Maximum Principle applied to a modified Stepanova model. This model directly accounts for the detrimental effects of chemotherapy on immune cell density. Because the parameter for this interaction is unknown, we run simulations while varying the parameter to observe the effect on the system. Our results show that combined dosages of chemo- and immunotherapy over the first days of the treatment period are sufficient to force the system to its healthy equilibrium. Copyright (C) 2021 The Authors.