Oshima, K., Takahashi, T., Mori, T., Matsuyama, T., Usuki, K., Asano-Mori, Y., . . . Kanda, Y. (2010). One-year low-dose valacyclovir as prophylaxis for varicella zoster virus disease after allogeneic hematopoietic stem cell transplantation. A prospective study of the Japan Hematology and Oncology Clinical Study Group. Transplant Infectious Disease, 12, 421–427.

To determine the cumulative incidence of varicella-zoster virus (VZV) two years after transplant.

Following allogeneic hematopoietic stem cell transplant (HSCT), patients received low-dose valacyclovir (VCV) for prophylaxis against VZV.  Up to day 35, patients received oral acyclovir (ACV) 1,000 mg/day, and then from days 36 to 365, they received oral VCV 500 mg/day three days a week.  Patients were monitored for VZV for two years after HSCT.

• Forty adult patients (57% male, 43% female) were included.
• Median age was 43 years (range 18–61).    
• Diagnosis for transplant: ten patients had acute myeloblastic leukemia, eight had acute lymphoblastic leukemia, four had chronic myelogeneous leukemia, five had myelodysplastic syndrome, nine had Hodgkin lymphoma, one had multiple myeloma, and three had severe aplastic anemia.
• Patients were excluded if they had renal or liver dysfunction, antithymocyte globulin, T cell-depleted graft, cord blood, or a hematologic malignancy and were not in remission prior to HSCT.
• Patients from ages 16 to 70 who were seropositive for VZV-IgG antibody prior to allogeneic HSCT.  Those enrolled were not necessarily as young or as old as the eligibility criteria.

• Multi-site
• Hospitals participating in the Japan Hematological Oncology Clinical Study Group

• Patients were undergoing posttransplant care.
• The study has clinical applicability for antimicrobial prophylaxis in a transplant setting.

This was a prospective, nonrandomized study.

• Development of VZV    
• Dermal development of VZV (defined as generalized cutaneous distribution or characteristic vesicular skin lesions on an erythematous base within a dermatome)
• Visceral development of VZV
• Toxicities of VCV
• Postherpetic neuralgia
   

Breakthrough VZV occurred in two patients while receiving VCV.  After stopping VCV prophylaxis, an additional five patients developed VZV disease.  These seven patients had a favorable response to oral or intravenous VCV given at therapeutic doses.  Univariate analysis revealed no factors that significantly associated patients with incidence of VZV.

For patients undergoing allogeneic HSCT, one year of low-dose VCV is safe and effective for preventing VZV.

Small sample size

Patients undergoing allogeneic HSCT may benefit from the safe use of low-dose prophylactic VCV (500 mg/day three times a week) for VZV in the posttransplant setting.