Study to Determine the Maximum Tolerated Dose, Safety and Effectiveness of Pomalidomide for Patients With Sickle Cell Disease

Inclusion Criteria: * Ages 18 to 60 years, inclusive, at the time of signing the informed consent form * Clinically significant Sickle Cell Disease (SCD) documented as Sickle Cell Anemia or Sickle Beta-Zero Thalassemia * Clinically significant SCD defined as at least 1 documented pain episode per year averaged over the past 3 years or one episode of active leg ulcers, priapism, or acute chest syndrome over the past 3 years * Failed to achieve at least an absolute 5% increase in hemoglobin F while taking Hydroxyurea (HU) or unable to tolerate HU as described by the treating physician and may include but is not limited to lack of efficacy (such as people who have continued to have pain episodes more than 2 times a year or who have had acute chest or multiorgan failure syndromes or an episode of priapism), or other severe side effects while on HU (severe side effects include significant myelosuppression; skin cancer; or cytotoxicity evidenced by gastrointestinal symptoms, dermatological reactions, hepatic enzyme elevations, pulmonary fibrosis or neurological disturbances), or refusal of hydroxyurea therapy by the informed patient * Able to adhere to the study visit schedule and other protocol requirements * Females must be surgically sterile (post hysterectomy or bilateral oophorectomy) or naturally postmenopausal for at least 24 consecutive months (i.e., have not had menses at any time in the preceding 24 consecutive months) * Male subjects must agree to use a latex condom dur…