Efficacy of Daratumumab to Overcome Platelet Transfusion Refractoriness in Patients with Aplastic Anemia

Inclusion Criteria: * Diagnosis of aplastic anemia (AA) * Dependent on platelet transfusions, characterized by either PLT\<10×10\^9/L, or PLT\<20×10\^9/L with bleeding events. * Diagnosed with platelet transfusion refractoriness, characterized by Corrected count increment (CCI) \<7500/ul at 60 min, or CCI \<4500/ul at 24 hrs. * Male or female age ≥ 12 years * ECOG performance status ≤2 * Willing and able to comply with the requirements for this study and written informed consent. Exclusion Criteria: * The inherited bone marrow failure syndromes * The presence of hemolytic PNH clone * Combination of either radiotherapy or chemotherapy for solid tumors in recent 3 years, excluding the local tumor diagnosed 1 year ago and cured by surgical resection. * Cytopenia caused by other diseases, including liver cirrhosis, active rheumatic connective tissue disease, and persistence of infectious diseases, etc. * Uncontrolled infection * HIV, HCV or HBV active infection * The presence of any of the following bleeding events: * Gastrointestinal bleeding * Respiratory tract hemorrhage * Central nervous system bleeding * Abnormal liver function: ALT or AST \> 2 ULN, or TBil \> 2 ULN after treatment. * Abnormal kidney function: Creatinine clearance \< 30 ml/min * Heart failure (NYHA class III or IV) * Poorly controlled diabetes, characterized by fasting blood glucose \> 8.8mmol/L or post-meal blood glucose \> 11.1mmol/L after therapy with insulin or oral hypoglycemic agents * History of congestive heart failure, unstable angina pectoris, myocardial infarction, arterial or venous thrombosis * Pregnant or breast-feeding patients * Had a history of any psychiatric diseases, cerebrovascular disease or cognitive sequelae of head injury. * Participation in another clinical trial within 4 weeks before the start of this trial * Have an allergy to Daratumumab or any other part of this medicine. * Previously treated with Daratumumab * Previously treated with ATG/ALG within 4 months before the start of this trial * Previously treated with the anti-CD20 monoclonal antibody within 2 months before the start of this trial * Currently treated with TPO-RA except for a minimum of 4 weeks for washout before the start of this trial * Patients considered to be ineligible for the study by the investigator for reasons other than above