Hematologic adverse events associated with prolonged valganciclovir treatment in congenital cytomegalovirus infection

Background: Valganciclovir (2/d) therapy for 6 months in neonates with symptomatic congenital cytomegalovirus (cCMV) infection improves hearing and neurodevelopmental outcome. The only reported adverse event was neutropenia. Since 2009, our protocol for symptomatic cCMV infection was a 1-year treatment of 2/d for the first 3 months followed by 9 months of 1/d. Methods: A retrospective study. Infants with cCMV treated with valganciclovir for 1 year were recruited. Data of drug-related hematologic adverse events were collected. Results: One hundred sixty infants were eligible; 46 (28.8%) had experienced at least 1 episode of neutropenia (58 episodes), the majority (39/46, 84.8%) during the first 3 months of treatment and 7 (15.2%) during the last 9 months of treatment. Grades 3 and 4 neutropenia occurred in 9 (5.6%) children, almost exclusively during the first 3 months of treatment. Anemia (hemoglobin <9 g/dL) was recorded in 12 (7.5%) children during the first 3 months of 2/d treatment. Four children presented with hemoglobin levels <7 g/dL and needed a blood transfusion. One child was diagnosed with transient pure red cell aplasia. No long-term adverse events were recorded. Conclusions: Although prolonged valganciclovir treatment for cCMV is safe, a close monitoring of the white blood cell count and hemoglobin levels is warranted. Much lower rates of grades 3 and 4 neutropenia were observed than previously reported, probably owing to our unique treatment protocol. Nevertheless, drug-induced anemia should be of primary concern. The optimal protocol assessing clinical outcome, concurrently with potential side effects, has not yet been determined.