Comparing the Efficacy of Different Durations of Maribavir Treatment Regimens in Allo-HSCT

Inclusion Criteria:

1. First allogeneic hematopoietic stem cell transplantation;
2. Age ≥ 18 years;
3. Confirmed refractory CMV infection;

   Refractory CMV infection is defined as fulfillment of any one of the following criteria:
   * Persistent or increasing CMV viremia despite ≥2 weeks of appropriate antiviral therapy-specifically, CMV DNA levels remain unchanged (i.e., change ≤ log₁₀) or increase (i.e., change \> log₁₀)-concomitant with lack of clinical improvement or ongoing disease progression;
   * Drug-resistant CMV infection-defined as detection of specific CMV gene mutations associated with reduced susceptibility to one or more anti-CMV agents, in patients who otherwise meet the criteria for refractory CMV infection;
   * Intolerance to anti-CMV therapy-defined as inability to continue antiviral treatment due to severe adverse effects, such as clinically significant bone marrow suppression or renal impairment;
4. Provision of written informed consent and willingness to participate in this clinical study.

Exclusion Criteria:

1. Known allergic constitution, particularly hypersensitivity to any component of maribavir;
2. Active hepatitis B infection, defined as HBV DNA level ≥ 1 × 10³ IU/mL;
3. Confirmed HIV infection;
4. Severe impairment of major organ function, including but not limited to respiratory failure, cardiac failure, decompensated hepatic insufficiency, or renal insufficiency;
5. Central nervous system CMV infection;
6. History of substance use disorder or chronic alcoholism that may compromise the validity or interpretation of trial outcomes;
7. Presence of a psychiatric disorder or cognitive impairment precluding the provision of informed consent;
8. Any other condition deemed by the investigator to render the participant unsuitable for enrollment in this clinical trial.