Questionable benefit of prophylactic acyclovir in renal transplant recipients at high risk for cytomegalovirus disease

Prophylactic acyclovir may help to prevent or ameliorate cytomegalovirus (CMV) disease in high-risk renal transplant recipients who are CMV-seronegative pre-transplant and receive a kidney from a CMV-seropositive donor. We evaluated the efficacy of prophylactic acyclovir by comparing the incidence and severity of CMV disease in high-risk acyclovir-treated patients (n=28)) with that of historical controls (n= 21). Acyclovir was administered for 12.0±4.9 weeks (800 to 3200 mg/ day p.o. with dose adjusted for renal function). Patients and controls did not differ with respect to age, sex, the number of AB and DR major histocompatibility mismatches, panel-reactive antibody status, or diabetes. Clinical CMV disease (fever with positive blood culture/antigen or fourfold rise in antibody titer) developed in 50% of acyclovir-treated patients and in 71% of controls (p=0.13). When adjustment was made for possible differences between acyclovir patients and controls using logistic regression, the effects of acyclovir on CMV disease were not statistically significant. The severity of CMV disease measured by the duration of fever, days of hospitalization, white blood count nadir, and changes in hepatic enzymes were similar between the groups. These results suggest that acyclovir had little effect on the incidence and severity of CMV disease in these high-risk renal transplant recipients, and that additional randomized controlled trials are needed to define the role of acyclovir prophylaxis.