Macimorelin (AEZS-130)-stimulated growth hormone (GH) test: Validation of a novel oral stimulation test for the diagnosis of adult GH deficiency

Jose M. Garcia*, R. Swerdloff, C. Wang, M. Kyle, M. Kipnes, B. M.K. Biller, D. Cook, K. C.J. Yuen, V. Bonert, A. Dobs, M. E. Molitch, G. R. Merriam

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

50 Scopus citations


Context: In the absence of panhypopituitarism and low serum IGF-I levels, the diagnosis of adult GH deficiency (AGHD) requires confirmation with a GH stimulation test. Macimorelin is a novel, orally active ghrelin mimetic that stimulates GH secretion. Objective: The objective of the study was to determine the diagnostic efficacy and safety of macimorelin in AGHD. Design: This was a multicenter open-label study comparing the diagnostic accuracy of oral macimorelin with that of arginine+GHRH in AGHD patients and healthy, matched controls. After 43 AGHD patients and 10 controls were tested, the GHRH analog Geref Diagnostic [GHRH(1-29)NH2] became unavailable in the United States. The study was completed by testing 10 additional AGHD patients and 38 controls with macimorelin alone. Main Outcome Measure: Peak GH area under the receiver operating characteristic curve after macimorelin was measured. Results: Fifty AGHD subjects and 48 controls were evaluated. Peak GH levels in AGHD patients and controls after macimorelin were 2.36 ± 5.69 and 17.71 ± 19.11 ng/mL, respectively (P < .0001). With macimorelin, the receiver operating characteristic analysis yielded an optimal GH cut point of 2.7 ng/mL, with 82% sensitivity, 92% specificity, and 13% misclassification rate. For subjects receiving both tests, macimorelin showed discrimination comparable with arginine+GHRH (area under the receiver operating characteristic curve 0.99 vs 0.94, respectively, P = .29). Obesity (body mass index > 30 kg/m2) was present in 58% of subjects, and peak GH levels were inversely associated with body mass index in controls (r = -0.37, P = .01). Using the separate cut points of 6.8 ng/mL for nonobese and 2.7 for obese subjects reduced the misclassification rate to 11%. Only 1 drug-related serious adverse event, an asymptomatic QT interval prolongation on the electrocardiogram, was reported. Conclusion: Oral macimorelin is safe, convenient, and effective in diagnosing AGHD with accuracy comparable with the arginine+GHRH test.

Original languageEnglish (US)
Pages (from-to)2422-2429
Number of pages8
JournalJournal of clinical endocrinology and metabolism
Issue number6
StatePublished - Jun 2013

ASJC Scopus subject areas

  • Biochemistry, medical
  • Endocrinology
  • Biochemistry
  • Clinical Biochemistry
  • Endocrinology, Diabetes and Metabolism


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