The purpose of this study is to assess the safety, tolerability, pharmacokinetic, and pharmacodynamic effects of Aes-103 (active ingredient 5-hydroxymethyl-2-furfural [5-HMF]) compared with placebo in subjects with stable sickle cell disease (SCD). Safety will be measured by monitoring adverse events (AEs), electrocardiograms (ECGs), vital signs, and laboratory values. Pharmacokinetics of Aes-103 will be measured over time in plasma, red blood cell hemolysate and binding of Aes-103 to hemoglobin. Pharmacodynamic effects will be assessed by measuring partial pressure of oxygen at which 50% of hemoglobin is saturated with oxygen (p50) while breathing normal air, blood oxygen levels (SpO2), ex-vivo antisickling effects in a hypoxic environment, and by imaging related changes in tissue blood flow and oxygen levels.

Inclusion Criteria:

• Be male or female, aged 18-65 years old, inclusive

• Have sickle cell disease (SCD) (hemoglobin SS) without hospitalization for pain crises in the 30 days before screening or for any SCD complications on more than two occasions in the past 12 months; subjects are allowed concomitant usage of hydroxyurea (HU) if the dosage is stable for the 2 months before screening and is at a dosage that does not exceed the product's labeling.

• Have normal laboratory values as defined below:

  • Direct bilirubin 0.1 to 1.0 mg/dL
  • Alanine transaminase (serum glutamic pyruvic transaminase) 6 to 41 IU/L
  • Creatinine for females 0.56 to 1.16 mg/dL and for males 0.77 to 1.19 mg/dL

• If female, be non-pregnant and non-breastfeeding and be surgically sterile or using an acceptable method of contraception throughout the study and for 30 days after study completion

• Have successfully completed an outpatient screening visit consisting of medical history, physical examination, 12-lead ECG, vital signs, hematology and chemistry tests, urinalysis, urine drug screen, pregnancy test (females), hemoglobin electrophoresis, hepatitis B and C screening, and HIV serology (Note: Subjects with abnormal screening values may be eligible if the results are not clinically significant, as judged by the investigator or medical monitor)

• Be able to understand and have provided written informed consent including signature on an informed consent form approved by an institutional review board

• Agree to abide by the study schedule and dietary restrictions and to return for the required assessments

• Be willing to abstain from foods high in 5-HMF (e.g., coffee, malt, barley, balsamic vinegar, dried fruits, and caramel products) for at least 3 days before each dosing

Exclusion Criteria:

• Have evidence of clinically significant cardiovascular, respiratory, renal, hepatic, pulmonary, gastrointestinal, hematological, neurological, psychiatric, or other disease that may interfere with the objectives of the study or the safety of the subject, as judged by the investigator in agreement with the sponsor or medical monitor, or have been hospitalized in the past 6 months as a result of these conditions
• Have been hospitalized in the 14 days before enrollment, for any reason
• Be currently on regularly scheduled transfusions
• Have received a transfusion within 2 weeks of administration of study drug
• Have taken herbal preparations in the 2 weeks before dosing (Note: subjects are allowed concomitant usage of HU and other scheduled prescription drugs if the dosage is stable for the 2 months before screening and is at a dosage that does not exceed the product's labeling. These scheduled prescription medications will be continued during the study [including during dosing]. All other medications, including over-the-counter medications used according to the product labeling, administered on an as-needed basis will be permitted except for the 24 hour period before dosing and the day of dosing. Medications for pain management will be allowed as needed [including during dosing.])
• Have taken any other investigational drug within 30 days or 5 half-lives before the screening visit, whichever is longer
• Consumed more than 14 alcoholic drinks per week or more than 3 drinks per day at any point in the past month
• Have received disulfiram or 4-methylpyrazole within 30 days before dosing
• Have taken any cough-cold product containing dextrorphan or dextromethorphan within 4 days before dosing
• Have positive result for urine drug test (cocaine, marijuana, opiates, amphetamines, methamphetamines, benzodiazepines, ethanol) at screening visit. However, use of opiates, amphetamines, or benzodiazepines is allowed if prescribed by a physician.
• Have engaged in strenuous exercise within 72 hours prior to dosing
• Be considered not suitable for participation in this study for any reason, as judged by the investigator
• Have pre-existing allergic or other adverse reactions to orange juice