“…Many optimal control strategies have been proposed for highlighting the advantage of optimization of some parameters in some biomathematical models. [9][10][11] In this context, some applied mathematicians advise to rely dosage problems; also, on their optimal control approaches, they see beneficial for developing therapeutic strategies that aim to reduce tumor volume with lesser side-effects, see, for instance, in the case of chemotherapy, the work in Yegorov and Todorov, 12 and in the case of immunotherapy, papers in Hamdache et al 13,14 Some research papers on mathematical medicine have developed mathematical models which describe the evolution of tumors 15,16 and analyze the different interactions between the tumor, immune-system, and treatment. 17,18 In this paper, we formulate a minimization problem from which we aim to find the optimal dose and duration of the BCG immunotherapy procedure in the case of superficial bladder cancer, based on a prevalidated mathematical model 19 in the form of 4 ordinary differential equations which describe the superficial bladder tumor-immune interactions after the injection of BCG in the bladder of a hypothetical patient.…”