A Phase 3, Multi-Center, Randomized, Double-Blind, Placebo-Controlled, Study of Fostamatinib Disodium in the Treatment of wAIHA

Inclusion Criteria: 1. Subject must have a diagnosis of primary or secondary warm Antibody Autoimmune Hemolytic Anemia (wAIHA) as documented by a positive direct antiglobulin test (DAT) specific for anti-IgG or anti-IgA. 2. Have failed or not tolerated at least one prior wAIHA treatment regimen, including steroids, rituximab, azathioprine, cyclophosphamide, cyclosporine, MMF, danazol, vincristine, ESA or splenectomy (folate, iron or other supplements do not fulfill this criterion). 3. Have haptoglobin \<LLN or total bilirubin \>ULN or lactate dehydrogenase (LDH) \>ULN. 4. At screening, subject's hemoglobin level must be ≤9 g/dL OR if hemoglobin value \>9 g/dL and \<10 g/dL, subject must be on an allowed wAIHA treatment AND the subject must have documented symptoms related to anemia (e.g., weakness, dizziness, fatigue, shortness of breath, chest pain). 5. Karnofsky performance status (KPS) ≥70. 6. Subject's concurrent treatment for wAIHA may consist of no more than two of any of the following agents: azathioprine, steroids, ESAs, mycophenolate mofetil, dapsone or danazol at a stable dose Exclusion Criteria: 1. Subject with other types of Antibody Autoimmune Hemolytic Anemia (AIHA) (e.g., cold antibody AIHA, cold agglutinin syndrome, mixed type AIHA, or paroxysmal cold hemoglobinuria). 2. Subject has AIHA secondary to autoimmune disease, including systemic lupus erythematosus (SLE), or lymphoid malignancy if the underlying disease is not stable or is not well-controlled on current therapy, per investigator medical judgement. 3. Subject has uncontrolled or poorly controlled hypertension, defined as systolic blood pressure ≥135 mmHg or diastolic blood pressure ≥85 mmHg, whether or not the subject is receiving anti-hypertensive treatment. 4. Subject has one or more of the following laboratory abnormalities at screening: neutrophil count of \<1,000/μL or platelet count of \<30,000/μL, unless due to Evans syndrome; transaminase levels (i.e., alanine aminotransferase \[ALT\] or aspartate aminotransferase \[AST\]) \>1.5 x ULN. 5. Has documented active hepatitis B or hepatitis C infection or HIV infection.