Inclusion Criteria:
* Subject is ≥19 years of age at the time of signing the informed consent form (ICF).
* Subject must understand and voluntarily sign an ICF prior to any study-related assessments/procedures.
③ Subject is willing and able to adhere to the study visit schedule and protocol requirements.
④ Subject has documented diagnosis of multiple myeloma, follicular lymphoma, or large B-cell lymphoma (including diffuse large B-cell lymphoma, high-grade B-cell lymphoma, transformed follicular lymphoma, or transformed marginal zone lymphoma), and is receiving one of the following bispecific antibodies: Multiple Myeloma: Teclistamab, Elranatamab, Talquetamab, Cevostamab, ABBV383 Lymphomas: Mosunetuzumab, Glofitamab, Epcoritamab, Odronextamab
⑤ Subject has documented clinically significant CMV infection, defined as: A. Onset of CMV end-organ disease (Appendix 1), or B. Initiation of anti-CMV pre-emptive therapy based on documented CMV viremia ≥500 IU/mL in two consecutive assessments (≥1 day apart) and the clinical condition of the subject Note: Prior therapy with ganciclovir, valganciclovir, foscarnet, or cidofovir is allowed.
* ECOG performance status of 0, 1, or 2. ⑦ Individual of childbearing potential (IOCBP) must: A. Have two negative pregnancy tests before study treatment, and agree to ongoing testing.
B. Commit to true abstinence or use two forms of contraception (one highly effective + one barrier method) starting 28 days prior to treatment, during treatment, and for 90 days after the last dose.
Note: Definition of IOCBP includes menstruating individuals who are not postmenopausal for 12+ months or have not undergone permanent sterilization.
⑧ Male subjects must: A. Practice true abstinence (monthly verified) or use a condom with partners who are pregnant or of childbearing potential during treatment, dose interruptions, and for 90 days after last dose, regardless of vasectomy status.
⑨ Male subjects must not donate sperm during treatment and for 90 days after the last dose.
⑩ Female subjects must not donate eggs during treatment and for 90 days after the last dose.
Exclusion Criteria:
* Requires ganciclovir, valganciclovir, foscarnet, or cidofovir for non-CMV indications or requires co-administration with maribavir.
* Known hypersensitivity to maribavir. ③ CMV disease involving the CNS (retinitis alone is allowed). ④ Received allogeneic SCT within 1 year or autologous SCT within 12 weeks prior to study treatment.
Allogeneic SCT recipients must not have active GVHD. ⑤ Any significant medical condition, infection, lab abnormality, or psychiatric illness posing unacceptable risk.
* Any condition that may confound data interpretation. ⑦ Any of the following laboratory abnormalities:
A. Creatinine clearance \<10 mL/min or requiring dialysis (Cockcroft-Gault formula used):
* Males: CrCl = (140 - age) × weight (kg) / (72 × creatinine \[mg/dL\])
* Females: Multiply above result by 0.85 B. AST or ALT \>5 × ULN C. Total bilirubin \>3 × ULN (except Gilbert's syndrome)
* Gastrointestinal disease or surgery (e.g., gastric bypass) that affects maribavir absorption.
* Severe vomiting, diarrhea, or GI illness within 24 hours before first dose. ⑩ Use of immunosuppressive medication within 14 days before study treatment, except: A. Intranasal, inhaled, topical, or local corticosteroid injections B. Systemic corticosteroids ≤10 mg/day of prednisone or equivalent C. Premedication for hypersensitivity (e.g., CT scan premed) ⑪ Requires mechanical ventilation or vasopressors at enrollment. ⑫ Positive for HIV, active or chronic HBV, active HAV or HCV: A. Known HIV infection B. Positive HBsAg (acute or chronic); HBV DNA PCR required for anti-HBcAb(+) patients.
* EXCEPTION: Isolated anti-HBs with known HBV vaccination
* EXCEPTION: anti-HBc(+), HBsAg(-), anti-HBsAb(-) with negative HBV DNA C. HCV antibody and RNA positive ⑬ Pregnant, breastfeeding, or planning pregnancy during study participation.
