Valacyclovir in Preventing Cytomegalovirus Infection in Patients Who Are Undergoing Donor Stem Cell Transplantation

OBJECTIVES: * Compare the occurrence of serious invasive fungal or bacterial infections during the first 270 days after transplantation in cytomegalovirus (CMV)-negative patients receiving a CMV-positive allogeneic stem cell transplantation and valacyclovir or placebo. * Compare the occurrence of primary CMV infection within the first 100 days after transplantation in patients treated with these regimens. * Compare the survival of these patients at 100 days and 270 days post-transplantation. * Compare the occurrence of CMV disease at day 100 and day 270 post-transplantation in patients treated with these regimens. * Compare the safety of these regimens in these patients. * Correlate the presence of CMV in stem cell product with post-transplantation CMV infection in these patients. * Determine if subclinical CMV infection results in a virus-specific immune response (humoral and cellular) in these patients. * Compare the quality of life of patients treated with these regimens. * Compare resource utilization (e.g., rates of hospitalization, number of days alive out of the hospital, days in the intensive care unit, days on mechanical ventilation, use of antimicrobials and filgrastim \[G-CSF\], and number of invasive procedures) in patients treated with these regimens. OUTLINE: This is a randomized, double-blind, placebo-controlled, multicenter study. Patients are stratified according to participating center and type of transplantation (matched related vs mismatched/unrelated). Patients are randomized to 1 of 2 treatment arms. * Arm I: Patients receive oral valacyclovir 4 times daily beginning with transplantation conditioning (usually day -5) and continuing until day 100 after transplantation. Patients receive high-dose acyclovir, instead of valacyclovir, IV every 8 hours beginning on day -1 and continuing until oral medications are tolerated. Allogeneic stem cells are infused on day 0. * Arm II: Patients receive oral or IV placebo on the same schedule as in arm I. Quality of life is assessed at baseline and on days 50 and 100. Patients are followed every 2 weeks for 6 months. PROJECTED ACCRUAL: A total of 115-230 patients (58-115 per treatment arm) will be accrued for this study within 2 years.