Prasugrel Versus Placebo in Adult Sickle Cell Disease

Inclusion criteria

• Adults with Sickle Cell Disease (SCD).
• Are greater than or equal to 50 kilograms (kg) at time of screening.
• Are not currently being treated with an investigational drug (use of hydroxyurea, which is not an investigational drug, is permitted under this protocol if the patient has been on a stable dose for at least 30 days prior to randomization and has no signs of hematological toxicity at screening.
• Agree to use a reliable method of birth control during the study or are women not of child-bearing potential due to surgical sterilization (hysterectomy or bilateral oophorectomy or tubal ligation) or menopause.

Exclusion criteria

• Acute painful crisis (requiring medical attention) within 30 days prior to screening.
• Have a concomitant medical illness (for example, terminal malignancy) that, in the opinion of the investigator, is associated with reduced survival over the expected treatment period (approximately 30 days).
• Severe hepatic dysfunction (cirrhosis, portal hypertension, or aspartate aminotransferase (AST) greater than or equal to 3x upper limit of normal [ULN]).
• Renal dysfunction requiring chronic dialysis.
• Contraindication for antiplatelet therapy.
• History of intolerance or allergy to approved thienopyridines.
• Have signs or symptoms of an infection.
• Hypertension (systolic blood pressure >180 millimeters of mercury (mm Hg) or diastolic blood pressure >110 mm Hg) at the time of screening or randomization.
• Hematocrit <18%.
• Any history of bleeding diathesis, bleeding requiring in-hospital treatment, or papillary necrosis.
• Active internal bleeding.
• History of spontaneous gastrointestinal (GI) bleeding requiring in-hospital treatment.
• Gross hematuria. Microhematuria, common in SCD patients, is not a contraindication.
• Platelet count <100,000 per cubic millimeter.
• Any history of intraocular hemorrhage.
• Prior history of transient ischemic attack (TIA), ischemic stroke, hemorrhagic stroke, or other intracranial hemorrhage.
• Known history of intracranial neoplasm, arteriovenous malformation, or aneurysm.
• Have clinical findings, in the judgment of the investigator, associated with an increased risk of bleeding.
• Have an international normalized ratio (INR) of greater than 1.5 at screening.
• Have had recent surgery (within 30 days prior to screening) or are scheduled to undergo surgery within the next 60 days.
• History of menorrhagia requiring medical intervention.