Abstract 13810: TT-00920, a Clinical Stage Novel Phosphodiesterase 9 Inhibitor, Protects Against Heart Failure in a Rat Model of Myocardial Infarction
Introduction: Phosphodiesterase 9 (PDE9) controls natriuretic-peptide-stimulated cyclic guanosine monophosphate in cardiac myocytes and is stongly upregulated in human heart failure, suggesting its potential as a promising therapeutic target in heart failure. Here we investigated the potential effects of TT-00920, a clinical stage novel and highly selective PDE9 inhibitor, on heart failure in a rat model of myocardial infarction. Methods: Myocardial infarction was induced by left anterior descending coronary artery (LAD) ligation in male Sprague Dawley rats. After 4-week treatment of vehicle, LCZ696, TT-00920, or TT-00920/Valsartan by oral gavage, efficacy was assessed by echocardiography and cardiac histopathology. Results: TT-00920 had remarkably improved cardiac function, protected against cardiac remodeling and fibrosis in a dose-dependent manner. TT-00920/Valsartan combination showed superior beneficial efficacy when compared to TT-00920 or LCZ696 single agent.Figure 1. TT-00920 improved cardiac function and ventricular remodeling.Figure 2. TT-00920 attenuated cardiac fibrosis in peri-infarct zone. Conclusions: TT-00920 reversed LAD-induced left ventricular dysfunction and remodeling, supporting its potential as a novel therapeutic agent for heart failure. The superior efficacy of TT-00920/Valsartan combination suggests that TT-00920 and renin-angiotensin-aldosterone system inhibitors may have additive therapeutic effects in heart failure.TT-00920 is currently being evaluated in Phase 1 clinical study for safety, tolerability, pharmacokinetics and pharmacodynamics in healthy volunteers (NCT04364789).