TRF-1101 Assessment in Sickle Cell Disease

Inclusion Criteria: * Be 18 years of age or older at the time of informed consent; * Have a diagnosis of homozygous sickle cell anemia or sickle cell-beta° thalassemia; * Have had 2 - 10 documented pain crises in the past year (pain crises are defined as visits to a medical clinic, Emergency Department or hospital, being bedridden and requiring constant analgesia at home for at least three days, or having a three-day interruption of life's activities \[i.e., school, work, planned leisure activity\] because of pain); * If female and of child bearing potential, have a negative serum or urine pregnancy test and be using an effective birth-control method with a history of reliability for the individual patient (use of mifepristone is not allowed); * Be properly informed of the nature and risks of the clinical investigation, be willing and able to comply with all clinical investigation-related procedures and assessments, and sign an Institutional Review Board (IRB) approved Informed Consent Form prior to entering the clinical investigation. Exclusion Criteria: * Have a history of abnormal bleeding, stroke, moya moya vascular malformations, or any other contraindication to anticoagulation; * Be currently taking anticoagulant or thrombolytic medication; * Be currently taking an endothelin receptor antagonist, e.g., bosentan (Tracleer®); * Have a known sensitivity or allergy to heparin or related drugs; * Have a history of thrombocytopenia (platelet count \< 100 x 103/mm3) induced by heparin or related drugs; * Have had fewer than 2 documented pain crises in the past year; * Have had a pain crisis within one month of screening or randomization; * If currently on or recently discontinued hydroxyurea treatment, have initiated or discontinued treatment or changed regimen within the past 6 months; * Have had a transfusion within last 120 days or have HbA% \> 15% from prior transfusion; * Creatinine levels \> 1.53 mg/dL (135 umol/L); * ALT levels ≥ 3 times normal; * Platelet count \< 100 x 103/mm3; * INR \> 2.0; * Be unable to tolerate oral medications; * Have unreliable venous access; * Be noncompliant with regular care; * Have a positive pregnancy test, be currently lactating, or be trying to become pregnant; * Have participation in an investigational drug or medical device study within previous 30 days; * Have any other condition or circumstance that in the opinion of the Investigator makes the patient a poor candidate for participation in the study.