Anamorelin: The First Approved Ghrelin Receptor Drug for Cancer-Related Muscle Wasting | Research

The takeaway

Anamorelin, a ghrelin receptor agonist approved in Japan for cancer cachexia, significantly increased lean body mass in clinical trials by stimulating appetite and growth hormone secretion, with a favorable safety profile.

Significant lean body mass increase
Anamorelin clinical trials demonstrated meaningful increases in lean body mass index in cancer cachexia patients, leading to its approval in Japan as the first ghrelin-targeted therapy for this condition

What the researchers found

Anamorelin led to a significant increase in lean body mass index in clinical trials.

Why it matters

This research highlights a potential treatment option for cancer cachexia, improving patients' quality of life. Understanding its effects can help manage weight loss in cancer patients more effectively.

How the study worked

The study is a review of clinical trials and pharmacological data on anamorelin.

What this study cannot tell us

The review may not cover all clinical trials or long-term effects of anamorelin.

How to read the evidence

This is a review of clinical trial data supporting anamorelin's regulatory approval in Japan. The underlying evidence includes phase 2 and phase 3 randomized controlled trials, though the drug was not approved in the US/EU due to questions about functional outcome improvement.

When this study was published

Published in 2022, this review covers anamorelin's path to Japanese approval and summarizes the clinical evidence that made it the first ghrelin receptor agonist approved for any indication worldwide.

The bigger picture

Cancer cachexia affects up to 80% of advanced cancer patients and is directly responsible for an estimated 20-30% of cancer deaths. Despite decades of research, treatment options have been extremely limited. Anamorelin's approval represents a breakthrough in the ghrelin receptor agonist field — demonstrating that targeting the hunger hormone pathway can produce clinically meaningful improvements in body composition. While it has not been approved in the US or Europe (where regulatory agencies sought evidence of functional improvement, not just body composition changes), its Japanese approval validates the ghrelin pathway as a therapeutic target for muscle wasting.

Questions still open

Could anamorelin be combined with exercise or nutritional support for greater functional improvement in cachectic patients?
Why has anamorelin not gained approval in the US and Europe despite positive lean body mass data?
Would newer ghrelin receptor agonists with improved brain penetration achieve better functional outcomes?

Common questions

What is cancer cachexia and why is it so serious?

Cancer cachexia is a complex syndrome causing severe muscle and weight loss that occurs in up to 80% of advanced cancer patients. It's not just about not eating enough — the body actively breaks down muscle due to inflammation and metabolic changes. Cachexia reduces quality of life, weakens patients so they can't tolerate cancer treatment, and directly contributes to death. Until anamorelin, there were virtually no approved drugs for this condition.

How does anamorelin work differently from nutritional supplements?

Nutritional supplements provide calories but don't address the underlying biological processes driving muscle wasting. Anamorelin activates the ghrelin receptor, which does two things: it increases appetite (so patients eat more) and stimulates growth hormone release, which in turn promotes muscle protein synthesis through IGF-1. This dual mechanism addresses both the intake and the metabolic sides of cachexia.

Read the original research

Anamorelin for cancer cachexia.

Drugs of today (Barcelona, Spain : 1998), 58(3), 97-104

View on PubMed ↗Publisher’s paper ↗

Citation

Nishie, Kenichi; Sato, Seiichi; Hanaoka, Masayuki. (2022). Anamorelin for cancer cachexia.. Drugs of today (Barcelona, Spain : 1998), 58(3), 97-104. https://doi.org/10.1358/dot.2022.58.3.3381585