A Phase 3 Trial to Compare IV BCV Versus IV CDV for Treatment of Adenovirus Infection After Allo-HCT

Inclusion Criteria: 1. Male and female, post-allo HCT within last 180 days, aged 2 months and older at time of signing informed consent form. 2. Subject/Guardian willing and able to understand and provide written informed consent to participate in the study. 3. In the investigator's judgement, the subject's clinical condition justifies treatment with IV BCV or IV CDV for AdV infection. 4. Has adenoviremia, based on any of: * AdV viremia DNA ≥10,000 IU/mL, OR * Two consecutive and rising AdV viremia DNA results of ≥1,000 IU/mL at screening, OR * AdV viremia DNA of ≥1,000 IU/mL, AND 1\. Lymphocyte count \<180/mm3, OR 2. Received T cell depletion, cord blood, or haploidentical transplant, OR 3. prior alemtuzumab, OR 4. anti-thymocyte globulin (ATG) Exclusion Criteria: 1. Subject received an allo-HCT with a matched sibling donor 2. Subject received more than 5 mg/kg of CDV for any reason in the 21 days prior to first dose of study drug. 3. Subject is allergic or hypersensitive to IV BCV or IV CDV or any of their components. 4. Subject received anti-AdV-specific cell-based therapy within 3 weeks prior to W1D1 or an anti-AdV vaccine at any time. 5. Subject has participated in any other investigational study within 30 days (or within 5.5 half-lives of the investigational product, whichever is longer) before signing the informed consent form (ICF), is currently participating in another interventional treatment trial with an investigational agent or is using an investigational device at the time of Screening.