Safety and effect of SANGUINATE on Sickle Cell Disease patients experiencing a vaso-occlusive crisis who are admitted to the hospital for treatment.

A single-blind, multicenter, randomized, placebo-control study in which 30 Sickle Cell disease patients having a vaso-occlusive crisis will either receive SANGUINATE 320 mg/kg/patient (8 mL/kg/patient) or Normal Saline on Day 1 (Visit 1) and Day 2 (Visit 2) infused over 2 hours each day. Patients are to remain in the hospital for up to 7 days but can be discharged at any time after receiving the second dose of SANGUINATE, provided their vaso-occlusive crisis has resolved and the patient has completed discharge procedures. Patients will have a follow-up phone call 7 days after discharge from the hospital to obtain safety, concomitant medication and pain assessments.

Inclusion Criteria:

1. Age ≥ 18 and ≤ 65 years of age
2. Diagnosis of Sickle Cell Disease (Hb-SS or any Genotype)
3. Pain-score due to vaso-occlusive pain crisis (VOC) ≥ 8 on a 10 point scale
4. VOC pain location ≥ 1 sites typical of vaso-occlusive crisis
5. Patients with Priapism, acute chest syndrome, and/or with other Sickle Cell Disease comorbidities can be enrolled with good judgment of the Investigator.
6. Signed and dated informed written consent by the subject
7. Able to receive intravenous infusion of SANGUINATE or Normal Saline
8. Women of childbearing potential with a negative serum pregnancy test and using a reliable method of contraception during the study period and for 30 days thereafter. Male study participants also agree to use contraception for 30 days after the study period

Exclusion Criteria:

1. In the judgment of the investigator, the patient is not a good candidate for the study
2. Females who are lactating and/or breastfeeding
3. Fewer than 14 days since prior infusion pain medication treatment for VOC
4. Medical history or evidence of moderate to severe renal insufficiency (estimated GFR < 60 mL/min) or chronic kidney disease, or of moderate to severe hepatic disease (ALTs > 5 x ULN)
5. Concurrent or prior treatment within 30 days of Screening with an investigational medication.
6. Symptoms or electrocardiogram (ECG)-based signs of acute myocardial infarction, unstable angina pectoris, decompensated heart failure, third degree heart block or cardiac arrhythmia associated with hemodynamic instability;
7. Severe or unstable concomitant condition or disease (e.g., known significant neurologic deficit, cancer, hematologic, metabolic or coronary disease), or chronic condition (e.g., psychiatric disorder), that, in the opinion of the Investigator, may increase the risk associated with study participation or study drug administration, or may interfere with the interpretation of study results;
8. Evidence or history of regular alcohol abuse
9. Screening laboratory result indicating serologic positivity for hepatitis C antibodies or hepatitis B surface antigens, unless explained by a documented vaccination.
10. Unable to comply with study attendance, protocol procedures or other study requirements;
11. Abnormal Echocardiogram at Study Entry (defined as Tricuspid Regurgitant Jet Velocity >3.1 m/sec).