Prevention of Cytomegalovirus Reactivation in Haploidentical Stem Cell Transplantation.

Cytomegalovirus (CMV) infection can increase the morbidity and mortality after allogeneic hematopoietic cell transplantation (HCT). Because of a higher degree of immunosuppression, haploidentical transplant recipients may be at an increased risk of viral infections, particularly CMV. We retrospectively analyzed 86 haploidentical HCT recipients at our institution to determine whether a more intensified antiviral strategy would reduce the incidence of CMV reactivation compared with a traditional antiviral prophylaxis regimen. According to practice changes over time in antiviral prophylaxis at our institution, patients were divided into the following 3 groups: hybrid (n = 15), traditional (n = 26), and intermediate dose (n = 45). The hybrid group received valganciclovir from admission to day -2 followed by standard-dose valacyclovir. The traditional group received standard-dose valacyclovir starting on day -1. The intermediate-dose group received ganciclovir from admission through day -2, followed by intermediate-dose valacyclovir. The hybrid and intermediate-dose groups were combined into an intensified group for further analysis. We found the cumulative incidence (CI) of CMV reactivation within 100 days post-HCT was higher for patients receiving the traditional strategy compared with the hybrid and intermediate-dose strategy groups (81% versus 53% versus 71%, respectively; P = .08) and was significantly higher when the traditional group was compared against the intensified group (81% versus 67%, respectively; P = .032). Median time to CMV reactivation was also shorter in the traditional group versus the intensified group (31 versus 41 days, respectively). Moreover, the CI of CMV disease by day 100 was significantly worse for patients receiving the traditional prophylaxis strategy among the 3 groups (8% traditional versus 0% hybrid versus 0% intermediate dose; P = .032). Renal toxicity did not differ between the traditional and intensified group. In conclusion, an intensified approach to prevention of CMV reactivation was associated with lower incidence of CMV reactivation and less CMV disease without increased toxicity. Because the most benefit was observed in the intensified group, further studies are needed to assess which antiviral intervention is the most beneficial on lowering the rates of CMV viremia and disease.