Understanding the relationship between drug pharmacokinetics (PK), pharmacodynamics (PD) and efficacy is critical to the successful development of new medicines. At present this relationship is primarily investigated using animals, this is time-consuming, ethically undesirable and prone to a lack of translation, particularly if animal and human PK differ significantly. This contributes to the low success rate of oncology medicines in the clinic.

At present there are a lack of in vitro alternatives to explore this relationship. In animals and humans drug concentration varies with time, whereas in vitro experiments are performed at fixed concentrations. This limits the translational relevance of the in vitro experiments.