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

K. Oshima, T. Takahashi, T. Mori, T. Matsuyama, K. Usuki, Y. Asano‐Mori, F. Nakahara, S. Okamoto, M. Kurokawa, Y. Kanda. 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
Transpl Infect Dis 2010: 12: 421–427. All rights reserved Abstract: Varicella zoster virus (VZV) disease is a frequent complication after allogeneic hematopoietic stem cell transplantation (HSCT). We carried out a trial of 1‐year low‐dose valacyclovir (VCV) prophylaxis against VZV disease to evaluate its efficacy and safety. Patients received oral acyclovir (ACV) 1000 mg/day until day 35 after HSCT. Oral VCV 500 mg/day, 3 times a week, was started on day 36 and continued until 1 year after HSCT. The development of VZV disease was monitored until 2 years after HSCT. A total of 40 patients with a median age of 43 years were enrolled. VCV was well tolerated in all but 1 patient who discontinued it on day 224 because of thrombocytopenia of unknown cause. Seven patients developed VZV disease at a median of 479 days (range 145–651) after HSCT, with a cumulative incidence of 18.5%. Two patients developed breakthrough disease during VCV prophylaxis. The other 5 patients developed VZV disease after the discontinuation of VCV, and 3 of these had developed extensive chronic graft‐versus‐host disease. Visceral involvement and serious complications were completely eliminated. All patients responded to the therapeutic dose of VCV or ACV. One‐year low‐dose VCV can be safely and effectively administered for the prevention of VZV disease after allogeneic HSCT.