A Safety and Tolerability Study of HJB647 in Heart Failure Participants With Reduced Ejection Fraction

Inclusion Criteria:

Participants eligible for inclusion in this study must meet all of the following criteria:

* Men and women aged 18 years or older
* Stable NYHA functional class II-III
* LVEF \<50%
* NT-proBNP ≥600 pg/ml if in sinus rhythm or ≥900 pg/ml if in atrial fibrillation at screening
* On stable standard of care therapy with sacubitril/valsartan with a dose of at least 49/51 mg BID for at least 4 weeks before screening.

Exclusion Criteria:

Participants will be deemed ineligible for inclusion if they meet any of the following exclusion criteria:

* Acute decompensated heart failure within 3 months prior to screening
* SBP \<105 mmHg at screening or baseline.
* Acute coronary syndrome, stroke, transient ischemic attack, cardiac, carotid or other major cardiovascular surgery, PCI, or carotid angioplasty within the 6 months prior to screening
* Hemodynamically significant mitral and/or aortic valve disease, or any prior valve replacement, except mitral regurgitation secondary to LV dilation at screening
* eGFR \<30 ml/min/1.73m2 at screening, as measured by the CKD-EPI formula
* BMI \>40 kg/m2
* Strong CYP3A4 inhibitors or inducers, sGC activators (vericiguat), PDE5 inhibitors, and nitroglycerin products
* Women of childbearing potential

Further eligibility criteria might apply in alignment with the trial protocol.