Macrilen, a new drug for the diagnosis of AGHD
Adult Growth Hormone Deficiency
Adult growth hormone deficiency (AGHD) is a rare disorder associated with increased morbidity and mortality. Just in the United States alone, there are currently more than 50,000 adults diagnosed with the condition.
AGHD can lead to multiple symptoms, including an increase in body fat, a decrease in muscle mass, weakness, fatigue, osteoporosis, an increased rate of fractures, dyslipidemia, cardiovascular disease, and impaired psychological well-being, such as anxiety or depression. The most common causes leading to the development of AGHD in adults are damage to the hypothalamus or pituitary gland that may have been caused by tumors, surgery, cranial radiation, or traumatic brain injury.
What Is Macrilen
Amongst the current testing available for AGHD, Macrilen offers a less invasive alternative. It is the first and only FDA-approved oral test for AGHD diagnosis, compared to the current intravenous and intramuscular options in the market. It also has a shorter test time for patients with no baseline blood draw needed. Additionally, there are no contraindications, there are some potential side effects: dysgeusia, dizziness, headache, fatigue, nausea, hunger, diarrhea, upper respiratory tract infection, hyperhidrosis, nasopharyngitis, sinus bradycardia. It is also noted that there the safety of Macrilen has not yet been established for subjects with a BMI > 40 kg/m2.
So, how does it work? Macrilen, a ghrelin agonist, stimulates the production of growth hormone (GH) in the pituitary gland. It acts as a synthetic version, acting similarly to endogenous ghrelin.
The Macrilen Clinical Study
Macrilen was used in a clinical trial compared to the insulin tolerance test (ITT), which is considered the gold standard. The data compared was based on rates of positive and negative agreement. Positive agreement was defined as the proportion of subjects who tested positive for AGHD with both the ITT and Macrilen tests. The negative agreement was conversely defined as the proportion of subjects who tested negative using both methods. The study gathered 140 adult subjects and split them into four groups based on the likelihood of GHD: high (n=38), intermediate (n=37), low (n=40), and healthy controls (n=25). The conclusion of the study demonstrated that the overall diagnostic accuracy of Marcilen was comparable to the ITT.
In patients with a high likelihood of AGHD, the positive agreement proportion between ITT and Macrilen was 89% and the negative agreement was 100%. Overall, for the high likelihood group, the proportion was 89%. In the intermediate group, agreement between Macrilen and the ITT was 67% positive, 86% negative, 70% overall. In the low likelihood group, The agreement proportions were 33% positive, 94% negative, and 85% overall. In the healthy control group, agreement was 0% positive, 96% negative, and 92% overall. When looking at all subjects, the agreement between Macrilen and ITT was 74% positive, 94% negative, and 84% overall. With these rates and the fact that Macrilen was well tolerated in the trial, it demonstrates that Macrilen is a viable alternative that may help us better diagnose AGHD.