Anamorelin and Conduction Defects: A Literature Review and Analysis of the Japanese Pharmacovigilance Database.

Background/aim: Cancer cachexia is characterized by weight loss with a specific decrease in skeletal muscle and adipose tissue. In Japan, anamorelin, which has a novel mechanism of action, was approved in 2021 for the treatment of cancer cachexia. However, little information is available on its safety in routine clinical care, in particular the occurrence of conduction defects as adverse reactions. Therefore, this study evaluated the risk and time to onset of anamorelin-related conduction defects by performing a literature review and evaluating the Japanese pharmacovigilance database.

Patients and methods: We reviewed the literature from April 2000 to June 2024 to identify reports of anamorelin-related conduction defects and analyzed data from April 2004 to December 2023 in the Japanese Adverse Drug Event Report (JADER) database. Using the database, we calculated reporting odds ratios (RORs) with 95% confidence intervals (CIs) and adjusted RORs (95%CIs) by considering whether patients were taking concomitant medications that can cause QT prolongation. In addition, we investigated outcomes and time to onset.

Results: The literature review identified seven cases of conduction defects. All cases occurred within approximately three weeks after starting treatment, and all patients recovered. The JADER database contained 537 cases of adverse reactions to anamorelin. The adjusted ROR (95%CI) of conduction defects was 20.00 (14.86-26.91), and the median time to onset was 13 days. Poor clinical outcomes occurred in only a few cases.

Conclusion: Performing frequent cardiac electrograms for two to three weeks after starting anamorelin may help to quickly identify anamorelin-related conduction defects.