A randomized, double-blind, placebo-controlled, mechanistic trial on the safety, tolerability and pharmacodynamics of ninerafaxstat in patients with angina and chronic coronary syndrome
Authors: Knuuti J , Nielsen R R , Bax J J , Gormsen L C , Flachskampf F , Jensen R V , Jespersen C W , Johnston N , Dehbi H M , Chamberlin P , Pryds K , Sorensen J , Held C , Loimaala A , Saraste A 
Published: October 2024

Abstract

Background/Introduction
Symptoms of angina resulting from reversible myocardial ischemia in chronic coronary syndromes have a negative impact on quality of life. Metabolic alterations are a key feature of ischemia, including reduced ATP generation by mitochondrial oxidative phosphorylation, NAD+ depletion, anaerobic glycolysis, proton & lactate accumulation leading to contractile dysfunction. Ninerafaxstat is a novel cardiac mitotrope that shifts metabolism from fatty acids towards glucose utilization, optimizing myocardial energy production during ischemia.

Purpose
We aimed to investigate the safety, tolerability, impact on myocardial glucose utilization and preliminary anti-ischemic efficacy of ninerafaxstat administered for 8 weeks to patients with symptomatic chronic stable angina who were on anti-anginal therapy and had evidence of myocardial stress hypoperfusion using 15O-H2O PET imaging.

Methods
IMPROVE-Ischemia was an international, randomized, double-blind, placebo-controlled mechanistic trial comparing ninerafaxstat vs. placebo in patients with symptomatic chronic coronary syndrome. The primary endpoint was the safety and tolerability of ninerafaxstat. Key efficacy evaluations were undertaken at baseline and end-of-treatment (Week 8) including imaging core laboratory assessments of 15O-H2O PET perfusion rest and stress imaging to quantify absolute myocardial blood flow (MBF), dobutamine stress echo with contrast for evaluation of LV contractile response during demand stress using the wall motion score index (WMSI) and, in a subgroup of subjects, 18F-FDG-PET imaging of myocardial glucose metabolism.

Results
The study randomized 58 subjects (mean age 68.6±7.1 years) with symptomatic stable angina and inducible hypoperfusion from 4 sites across 3 countries (Denmark, Finland, Sweden). 22% had type 2 diabetes and 50% had undergone percutaneous and/or surgical coronary revascularization. The majority (68%) were on ≥2 (up to 4) regular anti-anginals. Ninerafaxstat was well tolerated without impact on systemic hemodynamics. At Week 8, ninerafaxstat significantly increased myocardial glucose utilization and, in those with dobutamine-induced deterioration in wall motion at baseline assessment (n=25, pre-specified subgroup), resulted in a ~50% improvement in mean and peak stress WMSI, without altering rest or hyperemic stress MBF (Table 1).

Conclusion(s)
Treatment with ninerafaxstat was well-tolerated and showed a neutral hemodynamic profile. Ninerafaxstat significantly increased myocardial glucose utilization consistent with its mechanism of action and improved myocardial contractile response to dobutamine stress in subjects with baseline stress inducible deterioration of wall motion. These findings support a direct, metabolically-mediated, anti-ischemic effect of ninerafaxstat on top of existing anti-anginal agents, supporting its further development in cardiac pathologies characterised by ischemia.