Modulating Cardiac Energetics in Cardio-Metabolic Syndromes: A mechanistic, hyperpolarized MR Trial of Ninerafaxstat Treatment

Background Type 2 diabetes (T2D) and obesity are key contributors for heart failure (HF)- development, especially for HF with a preserved ejection fraction (HFpEF). On a molecular basis, excessive use of fatty acids (FA) induces lipotoxicity which in turn promotes inflammation, reduces mitochondrial pyruvate dehydrogenase (PDH) activity and impairs myocardial energetics and -function. Harnessing in-vivo, real time measurement of cellular metabolism via hyperpolarized pyruvate MR, we aimed to assess the effects of ninerafaxstat, a selective FA oxidation inhibitor, on cardiac energetics, metabolism & diastolic function in patients with cardio-metabolic syndromes. Methods IMPROVE-DiCE was an open-label, mechanistic phase 2a trial. 21 participants received 200mg ninerafaxstat twice daily for four (n=5) or eight weeks (n=16). Myocardial energetics (phosphocreatine to adenosine triphosphate ratio, PCr/ATP), metabolism and function were assessed pre-& post-treatment using magnetic resonance imaging (MRI), 31 P- and 1 H-MR spectroscopy (MRS). We utilised hyperpolarized [1- 13 C]pyruvate MRS to assess in-vivo PDH-flux (n=9) and plasma metabolomics and proteomics to assess whole body metabolism. Results Patients presented with impaired PCr/ATP, (median 1.6 [IQR 1.4, 2.1]), myocardial steatosis (2.2 % [IQR 1.5, 3.2]) and LV diastolic dysfunction (peak circumferential diastolic strain rate 0.86/s [IQR 0.82, 1.06]) at baseline. Ninerafaxstat treatment improved myocardial energetics by 32% ( p <0.01), reduced myocardial triglyceride content by 34% ( p =0.03) and showed a trend towards improved PDH-flux (mean 45% increase, p =0.08). Diastolic function was significantly improved post-treatment (peak diastolic strain rate by 10%, peak LV filling rate by 11%, both p <0.05). Conclusions Metabolic modulation with ninerafaxstat significantly improved myocardial energetics, reduced myocardial steatosis and improved LV diastolic filling. Combining hyperpolarized MRS and metabolomics, is a powerful approach to examine the mechanism of action of novel metabolic modulators. REGISTRATION URL: https://clinicaltrials.gov ; Unique identifier: NCT04826159 Abstract Figure