Off-Label Use of Letermovir as Preemptive Anti-Cytomegalovirus Therapy in a Pediatric Allogeneic Peripheral Blood Stem Cell Transplant

Abstract

Despite the effectiveness of the currently available antiviral drugs in treating cytomegalovirus (CMV) infection, high rates of adverse effects are associated with their use. Moreover, a problem of increasing importance is the emergence of drug-resistant CMV infection. Here, we describe the first case of off-label use of letermovir (LMV) as preemptive antiviral therapy, in a pediatric allogeneic peripheral blood stem cell transplant recipient with ganciclovir-resistant CMV infection who was intolerant to foscarnet and unable to achieve viral clearance after seven doses of cidofovir. After the administration of LMV, a gradual reduction in viral load was observed and within 6 weeks of LMV treatment, after more than 6 months of positive CMV-DNAemia, the patient cleared the infection. No adverse effects associated with LMV were observed during treatment. In this pediatric study case, the off-label use of LMV for the treatment of CMV infection has been well tolerated and proved to be effective in leading to the suppression of viral replication.

Keywords:

• pediatric allogeneic peripheral blood stem cell transplant
• GCV-resistant CMV
• intolerance to FOS
• off-label letermovir use

Acknowledgments

This research did not receive any specific grant from funding agencies in the public, commercial, or not-for-profit sectors. The authors would like to thank Dr. Marta Leone for contributing to data collection and their Linguistic Consultant, Lucy Scioscia, for editing the English language text.

Ethics and Consent Statement

The approval for off-label use of letermovir was obtained by the IRCCS St. Orsola Polyclinic of Bologna Drug-Ethics Committee (Prot. n. 19149/CF AVEC, on May 20, 2019). Written informed consent was obtained from the patient, having come of age during our monitoring, for the publication of this case report and the accompanying image. Institutional approval was not required to publish the case details.

Disclosure

The authors declare no conflicts of interest for this work.