December 21, 2017
The US Food and Drug Administration (FDA) has approved an orally available ghrelin agonist, macimorelin (Macrilen, Aeterna Zentaris), to be used in the diagnosis of patients with adult growth-hormone deficiency (AGHD).
Macimorelin stimulates the secretion of growth hormone from the pituitary gland into the circulatory system. Stimulated growth-hormone levels are measured in four blood samples over 90 minutes after oral administration of the agent for the assessment of growth-hormone deficiency.
Prior to the approval of macimorelin, the historical gold standard for evaluation of adult growth-hormone deficiency was the insulin tolerance test (ITT), an intravenous test requiring many blood draws over several hours.
The ITT procedure is inconvenient for patients and medical practitioners and is contraindicated in some patients, such as those with coronary heart disease or seizure disorder, because it requires the patient to experience hypoglycemia to obtain an accurate result.
Adult growth-hormone deficiency is a rare disorder characterized by the inadequate secretion of growth hormone from the pituitary gland. It can be hereditary; acquired as a result of trauma, infection, radiation therapy, or brain tumor growth; or can even emerge without a diagnosable cause. Currently, it is treated with once-daily injections of subcutaneous growth hormone.
"Clinical studies have demonstrated that growth-hormone stimulation testing for adult growth-hormone deficiency with oral ... macimorelin is reliable, well-tolerated, reproducible, and safe and a much simpler test to conduct than currently available options," said Kevin Yuen, MD, clinical investigator and neuroendocrinologist, Barrow Neurological Institute, and medical director of the Barrow Neuroendocrinology Clinic, Phoenix, Arizona, in a press release issued by Aeterna Zentaris.
"The availability of ... macimorelin will greatly relieve the burden of endocrinologists in reliably and accurately diagnosing adult growth-hormone deficiency," he added.
Aeterna Zentaris estimates that approximately 60,000 tests for suspected adult growth-hormone deficiency are conducted each year across the United States, Canada, and Europe.
"In the absence of an FDA-approved diagnostic test for adult growth-hormone deficiency, Macrilen fills an important gap and addresses a medical need for a convenient test that will better serve patients and health providers," said Michael V Ward, chief executive officer, Aeterna Zentaris.
Macrilen is expected to be launched in the United States during the first quarter of 2018.
It is also awaiting approval in the European Union.