Avatrombopag to Promote Platelet Engraftment After Allo-HSCT

Inclusion Criteria: * Male or female, aged between 18-60 years; * PLT\<20×10\^9/L after 14 days of allo-HSCT; * Expected survival time \> 3 months; * ECOG performance status 0-2; * Agree to receive the treatment of avatrombopag after Allo-HSCT and must sign the informed consent form. Exclusion Criteria: * Pregnant or lactating; * With severe and uncontrollable infection; * With graft-versus-host disease (GVHD) with steroid resistance; * With thrombotic microangiopathy; With active thromboembolism requiring anticoagulation * With detected disease recurrence due to chimerism by flow cytometry; * With chronic active hepatitis B and C virus infection; * With secondary or multiple transplantation, or multiple organ transplantation; * With severe heart disease, lung disease, diabetes and metabolic diseases; * HIV positive; * With a history of PLT dysfunction or bleeding disorders * With the active hepatic venous occlusion disease, or a history of clinically significant hepatic venous occlusion disease (The disease was defined as the abnormal condition of painful hepatomegaly after transplantation with bilirubin ≥ 6.0 mg/dL); * With progressive solid tumor; * With severe bleeding requiring transfusion of more than 2 units of red blood cells, or sudden drop of blood cell volume ≥10% within 7 days prior to screening; * With any other clinical trial of investigational product or device within 30 days prior to the baseline visit, except for observational study; * With treatment of thrombopoietin receptor agonist (TPO-RA) one month before enrollment; * Deemed unsuitable for enrollment by the investigator.