Acyclovir prophylaxis against herpes simplex virus infection in patients with leukemia. A randomized, double-blind, placebo-controlled study.

Twenty-nine adult patients with acute leukemia receiving timed sequential chemotherapy participated in a randomized, double-blind, placebo-controlled trial of acyclovir prophylaxis against reactivated herpes simplex virus infection. Patients with pretreatment antibody titers of 1:16 or greater received acyclovir or placebo starting 4 days after their initial chemotherapy. Treatment was given either for 32 days or until the patients were discharged from the hospital or until a culture-positive herpes simplex virus infection was found. Culture-positive herpes simplex virus infection developed in 11 of 15 patients who received placebo. No infection appeared in 14 patients who received acyclovir (p less than 0.00005). No obvious acute drug toxicity was seen. Recurrent infection was seen in 6 of 14 patients after cessation of acyclovir when retreated with chemotherapy, suggesting no effect on viral latency in these 6 patients. Acyclovir provided highly effective prophylaxis against reactivated herpes simplex virus infections in adult patients with acute leukemia receiving timed sequential chemotherapy.