Quantitative systems pharmacology models mechanistically describe a biological system and the effect of drug treatment on system behavior. Because these models rarely are identifiable from the available data, the uncertainty in physiological parameters may be sampled to create alternative parameterizations of the model, sometimes termed "virtual patients." In order to reproduce the statistics of a clinical population, virtual patients are often weighted to form a virtual population that reflects the baseline characteristics of the clinical cohort. Here we introduce a novel technique to efficiently generate virtual patients and, from this ensemble, demonstrate how to select a virtual population that matches the observed data without the need for weighting. This approach improves confidence in model predictions by mitigating the risk that spurious virtual patients become overrepresented in virtual populations. CPT Pharmacometrics Syst. Pharmacol.
Study HighlightsWHAT IS THE CURRENT KNOWLEDGE ON THE TOPIC? þ Parameter uncertainty in quantitative systems pharmacology models may be explored by the creation of virtual patients, which are typically weighted to form virtual populations to match clinical populations. Several algorithms designed to weight virtual patients have previously been published.• WHAT QUESTION DID THIS STUDY ADDRESS? þ Given that the parameters of a systems model are underconstrained, can we explore this uncertainty to efficiently generate physiologically reasonable patients and construct virtual populations where weighting is not necessary? • WHAT THIS STUDY ADDS TO OUR KNOWLEDGE þ This study outlines a methodology that improves on previous methods for efficiently generating and selecting virtual patients to match clinical population-level statistics. The final fitted populations will closely match empirical data, with all virtual patients weighted equally, which avoids the potential for overweighting certain solutions and skewing simulation results found in some previous algorithms.• HOW THIS MIGHT CHANGE CLINICAL PHARMACOLOGY AND THERAPEUTICS þ Generation of realistic virtual populations, and a deeper exploration of parameter uncertainty, should lead to better confidence in the predictions and better quantification of uncertainty of systems pharmacology models, particularly in the context of clinical trial simulations and analysis.Quantitative Systems Pharmacology (QSP) models are an effective approach for gaining mechanistic insight into the complex dynamics of biological systems in response to drug treatment.1-3 QSP models in the drug discovery and development process have been utilized for increased confidence in rationale for early development targets, preclinical to clinical translation, and predictions of clinical response to novel therapeutics. To be fit for this purpose, these models must include sufficient biological scope and mechanistic detail to link pathway modulation to overall system response. [4][5][6][7][8] Due to the complexity of the biology, the iterative model-building pro...