Association between the Pretreatment Body Mass Index and Anamorelin's Efficacy in Patients with Cancer Cachexia: A Retrospective Cohort Study.

Anamorelin (ANAM) is used to treat cancer-associated cachexia, a syndrome involving muscle loss and anorexia. The timing of the initiation of ANAM treatment is crucial to its efficacy. Although the body mass index (BMI) is a diagnostic criterion for cancer cachexia, no studies have explored its association with ANAM efficacy. We conducted a single-center, retrospective cohort study to investigate the association between the pre-treatment BMI and ANAM efficacy in patients with cancer-associated cachexia (n=47). The ANAM treatment was considered effective if the patient's appetite improved within 30 days of treatment initiation. We calculated a BMI cutoff value (19.5 kg/m2) and used it to divide the patients into high- and low-BMI groups. Their background, clinical laboratory values, cancer types, and treatment lines were investigated. Twenty (42.6%) had a high BMI (≥ 19.5 kg/m2) and 27 (57.4%) had a low BMI (< 19.5 kg/m2). High BMI was significantly associated with ANAM effectiveness (odds ratio 7.86, 95% confidence interval 1.99-31.00, p=0.003). Together these results indicate that it is beneficial to initiate ANAM treatment before a patient's BMI drops below 19.5 kg/m2. Our findings will help advance cancer cachexia treatment and serve as a reference for clinicians to predict ANAM's efficacy.