Baricitinib for Post-HSCT Persistent Thrombocytopenia

Inclusion Criteria: * Aged 18-70 years; * Underwent allo-HSCT; * Meet the diagnostic criteria for delayed platelet engraftment (DPE) or secondary failure of platelet recovery (SFPR); * Have platelet counts consistently \<20 ×10\^9/L or transfusion-dependent within 14 days prior to enrollment; * Have received adequate corticosteroid and TPO-RA therapy for persistent thrombocytopenia for no less than 4 weeks, with treatment failure or intolerance; * Complete donor chimerism. Exclusion Criteria: * Relapse of hematologic malignancy or MRD positivity; * Active infection; * Active graft-versus-host disease; * Thrombotic microangiopathy; * Primary graft failure or poor graft function; * Presence of other factors that may lead to secondary thrombocytopenia at the time of PT diagnosis; * History of systemic herpes zoster infection within 12 weeks prior to enrollment screening; * Acute or chronic infection with HBV, HCV, or HIV; * Evidence of active tuberculosis, or history of active tuberculosis without documented standard anti-tuberculosis treatment, or close contact with active tuberculosis without documented standard tuberculosis prophylaxis; * Receipt of a live vaccine within 12 weeks prior to enrollment screening, or planned receipt of a live vaccine during the study period; * Clinically significant thromboembolic event within 24 weeks prior to enrollment screening, or current use of anticoagulant medications deemed by the investigator to carry an uncontrollable risk; * Estimated glomerular filtration rate \<50 mL/min/1.73 m\^2; * Severe pre-existing or current conditions involving the cardiovascular, respiratory, hepatic, gastrointestinal, endocrine, nervous, or neuropsychiatric systems, or other severe or unstable illnesses or laboratory abnormalities that will make the study drug unacceptable for the patient or can interfere study data; * Participation in another clinical trial within 30 days prior to enrollment.