Association between discontinuation of anamorelin and immunotrophic index in patients with cancer-associated cachexia: a single-center retrospective study

Purpose Anamorelin, a ghrelin-like agonist, was the first drug approved for the treatment of cancer-associated cachexia in Japan; however, only a few studies have investigated what factors affect the discontinuation of anamorelin, and the observation periods of those studies were short. This study investigated the factors influencing the discontinuation of anamorelin after 4, 12, 24, and 48 weeks, to include longer observation periods than previously assessed. Methods This retrospective observational study investigated patients who received anamorelin for cancer-related cachexia between October 2021 and December 2023 at Kindai University Nara Hospital. We evaluated predictors of the discontinuation of anamorelin over 4, 12, 24, and 48 week observation periods after the start of treatment, and performed multivariate Cox regression analyses to calculate hazard ratios and 95% confidence intervals. Results Among the 93 patients included in this analysis, the median duration of administration (interquartile range) was 63 (2–674) days. Significant differences were observed for patients with a pre-treatment Eastern Cooperative Oncology Group Performance Status (PS) ≥ 2 in all observation periods, as well as a Prognostic Nutritional Index (PNI) ≤ 39.6 in the 12, 24, and 48 week observation periods. Conclusion This study revealed that a patient’s PS and PNI at the start of anamorelin therapy may affect the discontinuation of anamorelin. Therefore, in order to administer anamorelin for a longer period it is necessary to diagnose cancer-associated cachexia before PS and PNI begin to decline and start multidisciplinary intervention, including the administration of anamorelin.