A Study of the Efficacy and Safety of ICA-17043 (With or Without Hydroxyurea) in Patients With Sickle Cell Anemia.

Inclusion Criteria: * Homozygous (HbSS) Sickle Cell Anemia * Otherwise healthy (based on medical history, physical examination, 12-lead ECG, and clinical laboratory tests) * Patients may be receiving hydroxyurea, but must have been dose stabilized for at least 3 months * Patient has a history of at least one acute vaso-occlusive event requiring hospitalization Exclusion Criteria: * Patient participating in a chronic transfusion program * Patient having a total hemoglobin of \< 4.0 g/dL or \> 10.0 g/dL * Patient having a HbA \> 10% * Patient considering undergoing an elective surgery * Patient taking prohibited medications such as Epoetin, Warfarin, etc. * Patient who has had previous gastrointestinal surgery, except cholecystectomy or appendectomy * Patient with significant active cardiovascular, neurologic, endocrine, hepatic, or renal disorders unrelated to sickle cell anemia