Pharmacokinetic/pharmacodynamic (PK/PD) modeling and quantitative systems pharmacology (QSP) modeling are mathematical techniques which can be used to answer quantitative questions and enable decision-making across the drug discovery and development continuum. These approaches have sufficient flexibility and tractability to answer critical questions arising from early drug discovery to clinical development. As such, they are useful tools to increase efficiency and effectiveness in research and development (R&D), which can play an important role in offsetting the high cost and attrition of drug research. A recent publication by the Food and Drug Administration (FDA) states that quantitative systems pharmacology (QSP) modeling and simulation are seen as critical tools for accelerating drug development and assisting in regulatory decisions [1].