Virtual clinical QT exposure-response studies - A translational computational approach

Background and purpose: A recent paradigm shift in proarrhythmic risk assessment suggests that the integration of clinical, non -clinical, and computational evidence can be used to reach a comprehensive understanding of the proarrhythmic potential of drug candidates. While current computational methodologies focus on predicting the incidence of proarrhythmic events after drug administration, the objective of this study is to predict concentration -response relationships of QTc as a clinical endpoint. Experimental approach: Full heart computational models reproducing human cardiac populations were created to predict the concentration -response relationship of changes in the QT interval as recommended for clinical trials. The concentration -response relationship of the QT -interval prolongation obtained from the computational cardiac population was compared against the relationship from clinical trial data for a set of well -characterized compounds: moxifloxacin, dofetilide, verapamil, and ondansetron. Key results: Computationally derived concentration - response relationships of QT interval changes for three of the four drugs had slopes within the confidence interval of clinical trials (dofetilide, moxifloxacin and verapamil) when compared to placebo -corrected concentration- Delta QT and concentration- Delta QT regressions. Moxifloxacin showed a higher intercept, outside the confidence interval of the clinical data, demonstrating that in this example, the standard linear regression does not appropriately capture the concentration -response results at very low concentrations. The concentrations corresponding to a mean QTc prolongation of 10 ms were consistently lower in the computational model than in clinical data. The critical concentration varied within an approximate ratio of 0.5 (moxifloxacin and ondansetron) and 1 times (dofetilide, verapamil) the critical concentration observed in human clinical trials. Notably, no other in silico methodology can approximate the human critical concentration values for a QT interval prolongation of 10 ms. Conclusion and implications: Computational concentration -response modelling of a virtual population of highresolution, 3 -dimensional cardiac models can provide comparable information to clinical data and could be used to complement pre -clinical and clinical safety packages. It provides access to an unlimited exposure range to support trial design and can improve the understanding of pre -clinical -clinical translation.