The purpose of this study is to determine the safety and benefits of SG1002, including overcoming deficits in circulating hydrogen sulfide and nitrite found in heart failure patients, with secondary endpoints focused on improving clinical endpoints.

This will be a 3 month, placebo controlled double blind study, to determine whether 800 mg SG1002 given twice daily will be safe and will improve circulating levels of hydrogen sulfide and/or nitrite in heart failure subjects. In addition, secondary endpoints such as 6 minute walk distance, Minnesota heart failure questionnaire, biomarkers of inflammation and oxidative stress and cardiac remodeling will be assessed.

Inclusion Criteria:

• symptomatic heart failure, with New York Heart Association (NYHA) classification of stage III;
• be ambulatory;
• have left ventricular ejection fraction less than 40% within 6 months of screening;
• have heart failure that has been stable for the previous 3 months (defined by no change in baseline therapy or symptoms of heart failure for the previous 3 months)(changes in diuretics are permitted);
• if female, be either post-menopausal or surgically sterilised or willing to use an acceptable method of birth control (i.e., a hormonal contraceptive, intrauterine device, diaphragm with spermicide, condom with spermicide, or abstinence) from signing of the informed consent form though to the Final Visit/Early Termination Visit; and
• be willing and able to provide written informed consent.

Exclusion Criteria:

• pregnant or breastfeeding;
• has had any of the following within 3 months prior to screening: myocardial infarction, unstable angina, cerebrovascular accident, percutaneous coronary intervention, open heart surgery, cardiac resynchronisation therapy (CRT) or transient ischaemic attack (TIA);
• has serious cerebrovascular disease in the opinion of the PI;
• is unable to walk without the assistance of another person;
• has primary lung disease that is the major contributor to current symptom status;
• is currently participating in another interventional clinical study, or has participated in one within 30 days prior to screening;
• has an inability to speak English (due to need to administer standardised English-language questionnaires);
• has current symptomatic hypotension (defined as systolic blood pressure (SBP) ≤ 90 mmHg or diastolic blood pressure (DBP) ≤ 40 mmHg);
• has poorly controlled hypertension (defined as SBP ≥ 160 mmHg or DBP ≥ 100 mmHg) despite therapy;
• will have percutaneous coronary intervention or open heart surgery within 3 months of the screening visit;
• has serious liver disease;
• has poorly controlled diabetes (defined as HbA1c > 10.0 %);
• has hypersensitivity to sulfur or related compounds;
• uses sulfur containing products or supplements, such as dimethyl sulfoxide (DMSO) or methylsulfonylmethane (MSM);
• has renal insufficiency defined as eGFR < 30 mL/minute/1.73 m2 (Modification of Diet in Renal Disease Study MDRD);
• has a life expectancy of less than 6 months;
• has active malignancy requiring active anti-neoplastic therapy that will, in the opinion of the Investigator, interfere with study treatment or participation. (Stable basal cell skin cancer and cancers being treated solely with hormonal therapy are allowed);
• has evidence of drug or alcohol abuse within the past 3 years;
• has any other chronic illness that may, in the opinion of the Investigator, increase the risks associated with this trial.