SAN FRANCISCO-Low-dose intravenous acyclovir (Zovirax) provides
effective prophylaxis against Herpes simplex virus (HSV)
infection or reactivation in leukemic patients undergoing intensive
chemotherapy, Carole Miller, MD, said at the 35th Interscience
Conference on Antimicrobial Agents and Chemotherapy (ICAAC).
Furthermore, using IV acyclovir at dosages as low as 62.5 mg/m²
every 4 hours results in a 50% decrease in drug cost over standard
dosing, and the technique of administration does not increase
nursing time, said Dr. Miller, assistant professor of oncology,
Johns Hopkins University.
Until the advent of acyclovir, HSV infections were a significant
cause of morbidity in patients undergoing intensive high-dose
chemotherapy for leukemia, Dr. Miller pointed out.
About a decade ago, the effect of acyclovir as a prophylactic
agent against reactivation of HSV was assessed at Johns Hopkins
in a randomized, double-blind, placebo-controlled study. In this
earlier trial, 73% of the placebo group developed culture-positive
HSV infection from a mucocutaneous lesion, while none in the prophylaxed
group became positive.
To determine a minimal effective dose and schedule of acyclovir
for preventing HSV infection or reactivation, three studies were
set up, Dr. Miller said.
Overall, 517 persons with leukemia (AML-76%, ALL-16%, CML-8%)
undergoing intensive chemotherapy received 1,000 courses of prophylactic
acy-clovir with three consecutive regimens: 250 mg/m² q8h
for 309 courses; 125 mg/m² q6h for 225 courses; and 62.5
mg/m² q4h for 466 courses. The median duration of prophylaxis
was 36.9 days (the median duration of bone marrow aplasia).
Patients were evaluable if they received a minimum of 7 days of
acyclovir prophylaxis, as well as having all negative surveillance
cultures (throat, urine, blood) pre-acyclovir and within the first
72 hours of beginning prophylaxis.