A Novel Conditioning Regimen for Haploidentical Hematopoietic Stem Cell Transplant in Patients Aged ≥ 40 Years Old With Severe Aplastic Anemia

Inclusion Criteria:

Severe aplastic anemia; Age 40-60 years old; Weight 45Kg-100Kg; Eastern Cooperative Oncology Group (ECOG) score ≤3; No major organ injury (ECG ejection fraction >45%; bilirubin < 2 times the upper limit of normal value; AST and ALT < 3 times the upper limit of normal value; serum creatinine < 2 times the upper limit of normal value); No severe infection; Subjects voluntarily participated in this clinical trial and signed the informed consent.

Exclusion Criteria:

With other hematologic diseases who are not eligible for transplantation or who do not wish to receive transplantation; Expected survival of less than 1 month; Previous autologous or allogeneic hematopoietic stem cell transplantation; Pregnant patients; Patients with severe mental or neurological disorders that would affect the ability to provide informed consent and/or to report or observe adverse events; Other conditions that the investigator determines to be inappropriate for enrollment.

Current or recent (<4 weeks prior to screening) clinically serious viral, bacterial, fungal, or parasitic infection A history of symptomatic herpes zoster infection within 12 weeks prior to screening Active or chronic viral infection from hepatitis B virus (HBV), hepatitis C virus (HCV), or human immunodeficiency virus (HIV) Have evidence of active tuberculosis (TB), or have previously had evidence of active TB and did not receive appropriate and documented treatment, or have had household contact with a person with active TB and did not receive appropriate and documented prophylaxis for TB Exposure to a live vaccine within 12 weeks prior to enrollment or expected to receive a live vaccine during the study Have experienced a clinically significant thrombotic event within 24 weeks of screening or are on anticoagulants and in the opinion of the investigator are not well controlled Myocardial infarction (MI), unstable ischemic heart disease, stroke, or New York Heart Association Stage IV heart failure A history or presence of cardiovascular, respiratory, hepatic, gastrointestinal, endocrine, neurological, or neuropsychiatric disorders or any other serious and/or unstable illness that, in the opinion of the investigator, could constitute an unacceptable risk when taking investigational product or interfere with the interpretation of data

Any of the following specific abnormalities on screening laboratory tests:

1. ALT or AST >2 x ULN, or total bilirubin ≥1.5 x ULN
2. hemoglobin <9 g/dL, or total white blood cell (WBC) count <2,500/µL, or neutropenia (absolute neutrophil count <1,200/µL), or lymphopenia (lymphocyte count <750/µL)
3. eGFR <50 mL/min/1.73 m2