Phase Ib/IIa Trial With AC01 in Patients With HFrEF

Key Inclusion Criteria:

• Male and female out-patients of any ethnicity, between 18-80 years (inclusive), withstable HFrEF.

• Chronic HF for at least 6 months duration defined by history with current NYHA classII-III severity.

• LVEF ≤40% by TTE more than 6 months before screening and again at screening (screening measurement confirmed by echocardiography core lab).

• Sinus rhythm with mean resting heart rate 55-90 bpm.

• Cardiac Index 0.5-2.4 measured by Innocor at screening and Day -1. Screeningmeasurement confirmed by core lab.

• Transvenous ICD for primary prevention in place and active (as long as it is notsubcutaneous).

• Optimal guideline-based medical therapy for HFrEF as judged by the Investigator, atstable doses for ≥2 weeks with no intention to change dosing during trial duration.

Key Exclusion Criteria:

• Any cardiac rhythm that does or could interfere with ECG or TTE interpretation,including but not limited to permanent or persistent atrial fibrillation or flutteror paroxysmal atrial fibrillation or flutter with an episode in the last 3 months,frequent premature ventricular contractions, or atrial or ventricular pacing

• Ongoing or planned mechanical circulatory support, treatment with any IV vasoactivedrugs (vasodilators, inotropes, or vasopressors) or diuretics, and/or dialysis orhemofiltration or ultrafiltration.

• Probable alternative explanations for symptoms or signs (e.g., but not limited to,known primary cardiomyopathy [hypertrophic, constrictive, restrictive, infiltrative,congenital]). Primary uncorrected hemodynamically significant valve disease,right-sided HF not due to left-sided HF.

• History of aborted cardiac arrest and/or ICD for secondary prevention.

• Hospitalized for HF or received IV diuretics, vasodilators, or inotropes for HF ≤30days.

• Clinical diagnosis of acute coronary syndrome or stroke ≤30 days.

• PCI or percutaneous valve intervention ≤30 days or planned.

• Angina pectoris ≤30 days.

• Any cardiovascular procedure planned during study duration.

• Hospitalized or unplanned visit to the emergency department for any reason in last 30 days; patient is eligible 30 days from discharge from hospital.

• Use of any drugs or substances known to be strong inducers of CYP3A4 enzyme within 28 days prior to the dosing day and/or planned to be used during the overall studyperiod.

• eGFR by CKD-EPI <30 mL/min/1.73 m2 at screening or at Day -1.

• Serum or plasma potassium <3.5 or >5.2 mEq/L at screening or at Day -1. Alanineaminotransferase (ALT) or aspartate aminotransferase (AST) >3 times upper limit ofnormal (ULN) or total bilirubin >2 times ULN at screening or at Day -1. Or knowncirrhosis or severe liver or pancreatic disease, or Gilbert's syndrome.

• Any condition that in the opinion of the Investigator may interfere with adherenceto the protocol.

• Systolic blood pressure <90 mmHg or >140 mmHg at screening or at Day-1.

• Any of the following ECG findings: atrial or ventricular pacing, QTcF >450 ms, AVblock I with PQ > 240 ms, AV block II or III at screening and at Day -1. In the caseof non-paced QRS prolongation >120 ms, or if CRT is determined to be required and isactively pacing the ventricles, the QTcF is allowed to be up to but not greater than 470 ms.