An Assessment of Prasugrel on Healthy Adults and Sickle Cell Adults

Inclusion Criteria

• Are 50 to 100 kilograms (kg), inclusive, at the time of screening.
• Have signed informed consent.
• If female, 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.
• Control Subjects - Are healthy adults as determined by medical history, physical examination, and other screening procedures.
• Sickle cell disease (SCD) Subjects - Subjects on hydroxyurea must be on a stable dose for the 30 days prior to enrollment without signs of hematologic toxicity at screening.
• SCD Subjects - Are adults with SCD (hemoglobin SS [HbSS], Hb S beta0 thalassemia, Hb SC or Hb S beta+ thalassemia genotype) without a diagnosis of acute vaso-occlusive crisis (VOC) requiring medical intervention in an emergency department, infusion center, or as an inpatient) within the month prior to screening.

Exclusion Criteria

• 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 1 month).
• Exhibit severe hepatic dysfunction (cirrhosis, portal hypertension, or alanine aminotransferase [ALT] for aspartate aminotransaminase [AST]≥3 times upper limit of normal [ULN]).
• Exhibit severe renal dysfunction defined as Cockcroft-Gault creatinine clearance 300 red blood cells (RBC)/high-powered field (HPF) on urinalysis at the time of screening.
• History of previous intraocular hemorrhage which required treatment with surgery or laser, or evidence of active intraocular haemorrhage.
• Have a prior history of transient ischemic attack (TIA), ischemic stroke, hemorrhagic stroke or other intracranial hemorrhage.
• Have a 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) known to be >1.5 (INR testing not required for study entry).
• Have had recent surgery (within 30 days prior to screening) or are scheduled to undergo surgery within the next 60 days.
• Have a recent history of clinically significant menorrhagia.
• Have used any aspirin, warfarin, or thienopyridine in the 10 days prior to enrollment.
• Have used any non-aspirin non-steroidal anti-inflammatory drug (NSAID) in the 3 days prior to enrollment.
• Anticipate using aspirin, warfarin, NSAID, thienopyridine or other antiplatelet agent during the study period.
• Are women who are known to be pregnant, who have given birth within the past 90 days, or who are breastfeeding.
• Regular use of drugs of abuse and/or unacceptable positive findings on urinary drug screening (a positive urinary drug screening for sleep inducers or pain medications in subjects with SCD will be considered as an acceptable finding).
• Are currently enrolled in, or discontinued within the last 30 days from, a clinical trial involving an investigational drug or device or off-label use of a drug or device, or are concurrently enrolled in any other type of medical research judged not to be scientifically or medically compatible with this study.