Secondary Prophylaxis of CMV Infection Using Letermovir After HID-HSCT

Inclusion Criteria: \- (1) Underwent HLA-haploidentical donor HSCT, after at least 1 treated CMV episode since transplant in patients who did not receive primary prophylaxis. (2) Age elder than or equal to 18 years; (3) Informed consent may be signed by themselves. (4) HIV negative, HBV, HCV negative; (5) Informed consent must be signed before the start of the study procedures, and informed consent must be signed by the patient himself or his immediate family. Considering the patient 's condition, if the patient' s signature is unfavorable for disease treatment, the informed consent form should be signed by the legal guardian or the patient 's immediate family member Exclusion Criteria: * (1) received a previous allogeneic HSCT; (2) has evidence of CMV viremia from a central or local laboratory, or CMV end-organ disease within one week prior to enrollment; (3) received within 30 days prior to screening or plans to receive during the study any of the following: cidofovir, or any investigational anti-CMV therapy or biological agent; (4) has severe hepatic insufficiency (defined as Child-Pugh Class C; (5) has serum aspartate aminotransferase (AST) or alanine aminotransferase (ALT) \> 5 xthe upper limit of normal (ULN) or serum total bilirubin \> 2.5 x ULN. (6) has end-stage renal impairment with a creatinine clearance less than 10 mL/min. (7) has both moderate hepatic insufficiency AND moderate renal insufficiency; (8) Uncontrolled infection at enrollment; (9) requires…