Abstract
This paper proposes a novel Memetic Algorithm consisting of an Adaptive Evolutionary Algorithm (AEA) with three Intelligent Mutation Local Searchers (IMLSs) for designing optimal multidrug Structured Treatment Interruption (STI) therapies for Human Immunodeficiency Virus (HIV) infection. The AEA is an evolutionary algorithm with a dynamic parameter setting. The adaptive use of the local searchers helps the evolutionary process in the search of a global optimum. The adaptive rule is based on a phenotypical diversity measure of the population. The proposed algorithm has been tested for determining optimal 750-day pharmacological protocols for HIV patients. The pathogenesis of HIV is described by a system of differential equations including a model for an immune response. The multidrug therapies use reverse transcriptase inhibitor and protease inhibitor anti-HIV drugs. The medical protocol designed by the proposed algorithm leads to a strong immune response; the patient reaches a "healthy" state in one and half years and after this the STI medications can be discontinued. A comparison with a specific heuristic method and a standard Genetic Algorithm (GA) has been performed. Unlike the heuristic, the AEA with IMLSs does not impose any restrictions on the therapies in order to reduce the dimension of the problem. Unlike the GA, the AEA with IMLSs can overcome the problem of premature convergence to a suboptimal medical treatment. The results show that the therapies designed by the AEA lead to a "healthy" state faster than with the other methods. The statistical analysis confirms the computational effectiveness of the algorithm.