Letermovir for the Prevention of Cytomegalovirus Reactivation in Patients With Hematological Malignancies Treated With Alemtuzumab

Inclusion Criteria: * Confirmed diagnosis of T-cell or B-cell prolymphocytic leukemia, chronic lymphocytic leukemia, peripheral T-cell lymphoma, cutaneous T-cell lymphoma, or Sezary syndrome * Intent to treat with alemtuzumab. Monotherapy or combination with chemotherapy is allowed * Confirmed seropositivity for CMV IgG (\>= 0.7 U/mL) within 1 year of first letermovir dose * Confirmed lack of active CMV infection as evidenced by: * Undetectable CMV deoxyribonucleic acid (DNA) by Abbott RealTime CMV in vitro polymerase chain reaction assay (\< 50 IU/mL) within 7 days of first letermovir dose AND * Negative CMV IgM (\< 30 AU/mL) within 7 days of first letermovir dose * Able to provide informed consent * Life expectancy \> 4 months * Eastern Cooperative Oncology Group (ECOG) performance status =\< 3 * Highly unlikely to become pregnant or impregnate a partner by meeting at least one of the following: * A female subject who is not of reproductive potential is eligible without requiring the use of contraception. A female subject who is not of reproductive potential is defined as one who: * Has reached natural menopause (defined as 6 months of spontaneous amenorrhea with serum follicle-stimulating hormone \[FSH\] levels in the postmenopausal range as determined by the local laboratory, or 12 months of spontaneous amenorrhea) OR * Is 6 weeks post-surgical bilateral oophorectomy with or without hysterectomy OR * Has undergone bilateral tubal ligation. Spontaneou…