Anamorelin

Pharmaceutical

Anamorelin is an orally active, small-molecule agonist of the ghrelin/growth hormone secretagogue receptor (GHSR-1a). It was developed specifically to treat cancer cachexia — the debilitating loss of appetite, body weight, and muscle mass that accompanies many advanced cancers and is associated with poor tolerance of treatment and reduced survival. By mimicking the natural hormone ghrelin at its receptor, anamorelin is designed to stimulate appetite and promote gains in body weight and lean (muscle) mass, addressing a syndrome for which there are few effective options. Regulatory status differs sharply by region, so labeling here matters. Anamorelin is approved in Japan, where it is marketed as Adlumiz (approved in 2021) for cancer cachexia in patients with non-small cell lung cancer, gastrointestinal cancers, and pancreatic cancer. It is not approved by the US Food and Drug Administration. In the pivotal ROMANA phase 3 program, anamorelin improved lean body mass and appetite compared with placebo, but the FDA declined approval because the trials did not demonstrate a clear benefit on physical function — for example, handgrip strength did not improve alongside the gains in mass. As a result, anamorelin is classified as research-only in the United States and should not be regarded as an approved cachexia treatment there. Mechanistically, anamorelin activates GHSR-1a in both the hypothalamus and the pituitary. In the hypothalamus this drives appetite and food intake; in the pituitary it stimulates growth hormone release, which in turn raises insulin-like growth factor 1 (IGF-1) and supports an anabolic, muscle-preserving state. This dual appetite-plus-anabolic profile is what made ghrelin-receptor agonism an attractive strategy for cachexia, a condition where inflammation and metabolic dysregulation drive tissue breakdown that ordinary nutritional support alone rarely reverses. Anamorelin shares its target with several compounds discussed on this site. It reproduces the action of endogenous ghrelin, is chemically related in purpose to the diagnostic agent macimorelin (an approved oral GHSR-1a agonist), and belongs to the broader family of ghrelin-receptor agonists that includes the investigational prokinetic relamorelin and research secretagogues such as ibutamoren and ipamorelin. For the cachexia context in which anamorelin was developed, see our overviews of cancer cachexia and the use-case discussion of anamorelin in cancer cachexia. As always, cachexia is a serious, clinician-managed condition, and standard oncology and supportive care remain the foundation of treatment.