Abstract
The human and canine renin-angiotensin-aldosterone-systems (RAAS) play a central role in the pathophysiology of congestive heart failure (CHF), justifying the use of angiotensin converting enzyme inhibitors inhibitors (ACEi) in this indication. Seminal studies in canine CHF had suggested that the pharmacological action of benazepril was relatively independent of doses > 0.25 mg/kg P.O, thereby providing a rationale for the European label dose of 0.25 mg/kg P.O q24h in dogs with cardiovascular diseases. However, most of these earlier studies on benazepril pharmacodynamics relied on measures of ACE activity – a sub-optimal endpoint to characterize the effect of benazepril on the RAAS.
Nonlinear mixed-effects (NLME) modeling is an established framework for characterizing the effect of therapeutics on complex biological systems, such as the RAAS cascade. Importantly for therapeutic schedule optimization, one can use such a model to predict the outcomes of various hypothetical dosing schedules via simulation.
The objectives of this study were (i) to expand on previous NLME modeling efforts of the dose-exposure-response relationship of benazepril on biomarkers of the RAAS which are relevant to CHF pathophysiology and disease prognosis {angiotensins I, II, III, IV, (1-7)} by using a quantitative systems pharmacology (QSP) modeling approach; and (ii) to develop a software implementation of the model capable of simulating clinical trials in benazepril in dogs bedside dose optimization.
This study expands on previous modeling efforts to characterize the changes in RAAS pharmacodynamics in response to benazepril administration and showcase how QSP modeling can be used for efficient dose optimization of ACEis at the bedside. Our results suggest that 0.5 mg/kg PO q12h of benazepril produced the most robust reduction in AngII and upregulation of RAAS alternative pathway biomarkers. This model will eventually be expanded to include relevant clinical endpoints, which will be evaluated in an upcoming prospective trial in canine patients with CHF.
Author Summary Congestive heart failure (CHF) is a disease of the heart, common to both dogs and humans, where the heart is not healthy enough to pump blood around the body efficiently. Because the blood isn’t moving around the body as efficiently, it tends to get congested in various areas of the body and increases strain on the heart. Benazepril is a drug for CHF used in both dogs and humans to reduce congestion and improve the functioning of the cardiovascular system. Although benazepril is effective, there’s evidence that suggests the dosing could be improved if the therapeutic was further studied.
In this experiment, we tested benazepril at several safe dosages in well-cared for and healthy dogs to collect data on the relationship between dose size, dosing frequency, and effect on the cardiovascular system. Using this data, we built computer models of benazepril to simulate many clinical trials. By studying these simulations, we were able to make several predictions about the optimal dosing schedule of benazepril in dogs. We’ve also built a web-app version of the computer model for veterinary researchers to use, modify, and study. This work also provides a platform and roadmap for optimizing benazepril dosages in human CHF.
Competing Interest Statement
The potential conflicts of interest are that Ward and Mochel are consultants for Ceva Sante Animale; and Garelli-Paar, Guillot and Prikazsky are employees of Ceva Santa Animale.
