Doxorubicin PK/PD modeling in multiple myeloma: towards in silico trials

Doxorubicin (DOXO) is a well-known chemotherapy drug, which is widely used in the treatment of Multiple Myeloma (MM), a treatable but not curable type of blood cancer. Here, we propose a pharmacokinetics and pharmacodynamics (PK/PD) simulation environment, aimed at facilitating the optimization of DOXO treatment regimens in MM treatment. The resulting model has a transparent mechanistic structure, which facilitates its use and interpretation. The simulator was developed using a combination of experimental and modeling techniques, starting from in vitro PK/PD experiments conducted on MM cells. In our previous work, we carefully developed a PK model for DOXO in MM cells by fitting experimental data. We now devise a PD model from in vitro data investigating the effect of different concentrations of DOXO on cell growth and death in MM cell populations. The PK model is extended to enable a clear mechanistic link between the PK and the PD models, hence providing a complete PK/PD simulator. We show how the mathematical model can be exploited to simulate different DOXO administration protocols with different dosages, repetitions and exposure times, thus, making it possible to explore the effect of a wide range of treatment protocols easily.