An Integrative Approach for Improved Assessment of Cardiovascular Safety Data

Journal article, 2021

Cardiovascular adverse effects in drug development are a major source of compound attrition. Characterization of blood pressure (BP), heart rate (HR), stroke volume (SV), and QT-interval prolongation are therefore necessary in early discovery. It is, however, common practice to analyze these effects independently of each other. High-resolution time courses are collected via telemetric techniques, but only low-resolution data are analyzed and reported. This ignores co-dependencies among responses (HR, BP, SV, and QT-interval) and separation of system (turnover properties) and drug-specific properties (potencies, efficacies). An analysis of drug exposure-time and high-resolution response-time data of HR and mean arterial blood pressure was performed after acute oral dosing of ivabradine, sildenafil, dofetilide and pimobendan in Han-Wistar rats. All data were modelled jointly including different compounds, exposure- and response-time courses using a non-linear mixed effects-approach. Estimated fractional turnover rates (h-1, %RSE within brackets) were 9.45 (15), 30.7 (7.8), 3.8 (13) and 0.115 (1.7) of QT, HR, TPR and SV, respectively. Potencies (nM, %RSE within brackets) were IC50=475 (11), IC50=4.01 (5.4), EC50=50.6 (93) and IC50=47.8 (16), and efficacies (%RSE within brackets) were Imax=0.944 (1.7), Imax=1.00 (1.3), Emax=0.195 (9.9), and Imax=0.745 (4.6) for ivabradine, sildenafil, dofetilide and pimobendan. Hill-parameters were estimated with good precision, and below unity, indicating a shallow concentration-response relationship. An equilibrium concentration-biomarker response relationship was predicted and displayed graphically. This analysis demonstrates the utility of a model-based approach, integrating data from different studies and compounds, for refined pre-clinical safety margin assessment.