Trends in the Use of Anamorelin Hydrochloride for Cancer Cachexia: Examining the Timing of Anamorelin Initiation

Cancer cachexia is a clinically important condition associated with worsening nutritional status and difficulty in continuing anticancer treatment. Although multimodal approaches combining exercise, nutritional support, and pharmacological treatment may improve symptoms and delay disease progression, the optimal timing of pharmacological intervention remains unclear. Conventional diagnostic criteria have largely been based on Western populations and may not adequately identify patients at an earlier stage in Asian populations. In 2023, the Asian Working Group for Cachexia (AWGC) proposed diagnostic criteria more suitable for Asian populations; however, it remains unclear to what extent this change has been reflected in real-world prescribing practices for anamorelin. In this study, we examined the anamorelin prescribing trends before and after the introduction of the AWGC criteria and evaluated the associations of cachexia stage and baseline performance status (PS) with treatment continuation.

We conducted a retrospective chart review of patients who received anamorelin between April 2021 and March 2025 at Showa Medical University Hospital and Showa Medical University Northern Yokohama Hospital. The primary outcome was the duration of treatment continuation. Secondary evaluation focused on chronological changes in the PS. Prescribing patterns before and after the introduction of the AWGC criteria were compared, and subgroup analyses were performed according to Fearon's classification and baseline PS.

Of 130 patients prescribed anamorelin during the study period, data from 98 were included in the final analysis after exclusions. Overall, 68 and 30 patients were classified into the pre-AWGC and post-AWGC groups, respectively, with no major differences in key background characteristics or clear changes in the prescribing patterns between the groups. According to Fearon's classification, 90 and 8 patients had cachexia and pre-cachexia, respectively. The pre-cachexia group exhibited a significantly longer continuation duration than did the cachexia group (median: 211.5 vs. 34.5 days, log-rank p = 0.013). Patients with baseline PS of 0-1 demonstrated a significantly longer continuation duration than did those with a PS of 2-4 (median 71 vs. 25 days, log-rank p < 0.001). No marked deterioration in the PS over time was observed.

The prescribing patterns of anamorelin did not substantially change after the introduction of the AWGC criteria. Conversely, longer treatment continuation was observed in patients at an earlier stage of cachexia and in those with preserved baseline PS. Thus, in addition to updated diagnostic criteria, earlier intervention and initiation at a stage with better general condition may be important when optimizing the timing of anamorelin treatment.