Oral valacyclovir versus intravenous acyclovir in preventing herpes simplex virus infections in autologous stem cell transplant recipients

Patients who are seropositive for herpes simplex virus (HSV) and are undergoing autologous marrow or peripheral blood stem cell transplantation require prophylaxis for HSV infection. Most prophylaxis regimens have used intravenous acyclovir (ACY). Oral valacyclovir (VAL), the L-valyl ester of ACY, can be used to achieve plasma concentrations equivalent to levels achieved with intravenous ACY. In this study, adults undergoing autologous stem cell transplantation were randomized to receive ACY, 250 mg/m² intravenously (IV) every 12 hours from day 0 to engraftment, or VAL, 1 g orally every 12 hours from day 0 to engraftment. The primary study objective was to compare cost of HSV prophylaxis between study groups. Thirty patients were randomized to receive either oral VAL (n = 14) or IV ACY (n = 16) prophylaxis. Mean pharmacy cost of HSV prophylaxis in the patient group randomized to IV ACY was $1080 versus $320 for the group randomized initially to VAL. This study demonstrates the feasibility and significant cost savings of using oral VAL for HSV prophylaxis.