Real-World Safety and Effectiveness of Letermovir in Patients Undergoing Allogenic Hematopoietic Stem Cell Transplantation: Final Results of Post-Marketing Surveillance in Japan.

ABSTRACT

BACKGROUND AND OBJECTIVE: Cytomegalovirus (CMV) is a common opportunistic infection after allogenic hematopoietic stem cell transplantation (allo-HSCT). Letermovir, an inhibitor of CMV DNA terminase, is approved for CMV prophylaxis in allo-HSCT patients. We report the final results of post-marketing surveillance of letermovir in Japan. METHODS: The case report forms were drafted in part by the Japanese Data Center for Hematopoietic Cell Transplantation using data elements in the Transplant Registry Unified Management Program and sent to individual HSCT centers to decrease the burden of reporting. Hematopoietic stem cell transplantation patients who received letermovir between May 2018 and May 2022 were registered. Data collected included physician-assessed adverse events/adverse drug reactions and clinical effectiveness (development of CMV disease, CMV antigen status, and use of preemptive therapy). RESULTS: A total of 821 HSCT patients were included in the safety analyses. Adverse drug reactions occurred in 11.33% of patients, with serious adverse drug reactions in 3.05%. The five most common adverse drug reactions were nausea (1.58%), renal impairment (1.46%), and acute graft versus host disease, CMV test positive, and hepatic function abnormal (0.61% each). A total of 670 patients were eligible for effectiveness analyses. Among these patients, 16.57% and 28.66% required preemptive therapy through week 14 and week 48, respectively. In addition, relatively few patients developed CMV disease throughout the follow-up period (1.34% at week 14 and 3.85% at week 48). CONCLUSIONS: This final analysis of post-marketing surveillance with up to 48 weeks follow-up period in Japan provides further evidence supporting the safety profile and effectiveness of letermovir for CMV prophylaxis in patients undergoing allo-HSCT in real-world settings.

Cytomegalovirus (CMV) infection is common after allogenic hematopoietic stem cell transplantation and causes both directly and indirectly a serious disease that frequently results in the death or severe outcomes for the affected patient. Letermovir is a drug that inhibits CMV replication and infection and can be administered to prevent CMV infection in at-risk patients undergoing allogenic hematopoietic stem cell transplantation. After it was approved in Japan, a post-marketing surveillance was started in order to confirm the safety profile and effectiveness of letermovir in clinical practice in Japan. The data collected included the adverse drug reactions during treatment and the effectiveness of letermovir. In this article, we describe the final results of this survey. The most common adverse drug reactions were nausea (1.58% of patients), renal impairment (1.46%), and acute graft versus host disease, CMV test positive, and hepatic function abnormal (0.61% each). There were few cases of myelosuppression, which is frequently seen in patients treated with ganciclovir/valganciclovir, and blood cells recovered steadily over time. Cytomegalovirus antigens were detected in 38.36% of patients through 48 weeks. Preemptive therapy was initiated to 28.66% of patients for up to 48 weeks. Cytomegalovirus disease was infrequent, occurring in 3.85% of patients. Overall, these findings are in alignment with the currently approved product label and provide further evidence supporting the consistent safety profile and effectiveness of letermovir for CMV prophylaxis in patients in Japan undergoing allogenic hematopoietic stem cell transplantation in clinical practice.