A Phase III Safety and Efficacy Study of L-Glutamine to Treat Sickle Cell Disease or Sickle βo-thalassemia

Inclusion Criteria: * Patient is at least five years of age. * Patient has been diagnosed with sickle cell anemia or sickle ß°-thalassemia (documented by hemoglobin electrophoresis). * Patient has had at least two documented episodes of sickle cell crises within 12 months of the screening visit. * If the patient has been treated with an anti-sickling agent within three months of the screening visit, the therapy must have been continuous for at least three months with the intent to continue for the duration of the study. * Patient or the patient's legally authorized representative has given written informed consent. * If the patient is a female of child-bearing potential, she agrees to avoid pregnancy during the study and is willing and agrees to practice a recognized form of birth control during the course of the study (e.g. barrier, birth control pills, abstinence). Exclusion Criteria: * Patient has a significant medical condition that required hospitalization (other than sickle cell crisis) within two months of the screening visit. * Patient has prothrombin time INR \> 2.0. * Patient has serum albumin \< 3.0 g/dl. * Patient has received any blood products within three weeks of the Screening Visit. * Patient has uncontrolled liver disease or renal insufficiency. * Patient is pregnant or lactating or has the intention of becoming pregnant during the study (if female and of child-bearing potential). * Patient is currently taking or has been treated with any form of glutamine supplement within 30 days of the screening visit. * Patient has been treated with an experimental anti-sickling medication/ treatment within 30 days of the screening visit (with the exception of hydroxyurea in pediatric patients). * Patient is currently taking or has been treated with an investigational drug within 30 days of the screening visit (with the exception of hydroxyurea in pediatric patients). * Patient is currently enrolled in an investigational drug or device study and/or has participated in such a study within 30 days of the screening visit. * There are factors that would, in the judgment of the investigator, make it difficult for the patient to comply with the requirements of the study.