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Macrilen

Macimorelin acetate · Granule, for Solution

Prescription NDA RLD Official labelling
Informational index, not medical advice. Content is reproduced from public FDA and NLM data. Always confirm against the manufacturer's current prescribing information. Report adverse events to FDA MedWatch.

Overview

Brand name
Macrilen
Generic name
Macimorelin acetate
Dosage form
Granule, for Solution
Route
Oral
Marketing category
NDA · NDA
Labeler
Novo Nordisk
Product type
Human Prescription Drug
DEA schedule
Not scheduled
Active ingredients
2
NDC product codes
2
Packages
2
Data completeness
76% of corroborating sources present

Active ingredients

Source: NDC Directory
Active ingredients and strengths as listed in the NDC Directory.
Ingredient Strength RxCUI Monograph
Macimorelin 60 mg/1817mg — —
Macimorelin 60 mg/mg — —

Forms, strengths and routes

Source: NDC Directory
Dosage form
Granule, for Solution
Route of administration
Oral
Presentations
4

Pharmacologic classes are listed in the class section below.

Pharmacologic class

Source: NDC Directory
Established pharmacologic classes (EPC), mechanisms of action (MoA), chemical structures (CS) and physiologic effects (PE).
Class Type Browse
Growth Hormone Secretagogue Receptor Agonist [EPC] EPC 1 member — no class page
Growth Hormone Secretagogue Receptor Agonists [MoA] MoA 1 member — no class page

Regulatory status

Source: Drugs@FDANDC Directory
Application number
205598
Application type
NDA · New Drug Application
Approval date
December 20, 2017
Sponsor
AETERNA ZENTARIS
Products on application
1
Submissions recorded
3
Products approved under application 205598.
Product Trade name Form Strength Ingredient Status TE Flags
205598-001 MACRILEN FOR SOLUTION MACIMORELIN ACETATE Discontinued — RLD

Therapeutic equivalence

Source: Orange Book
TE code
—
Reference Listed Drug
Yes
Reference Standard
No

Codes beginning with “A” indicate products the FDA considers therapeutically equivalent. Codes beginning with “B” indicate bioequivalence has not been established. See methodology.

Patents and exclusivity

Source: Orange Book
Patent listings submitted under 21 U.S.C. 355(b)(1) and (c)(2).
Patent Expires Product Substance Use code Submitted
8192719 October 12, 2027 001 No U-2220 January 19, 2018
8192719*PED April 12, 2028 001 No —
Regulatory exclusivity periods.
Code Expires Product
M-14 July 23, 2029 001
PED January 23, 2030 001

Approval history

Source: Drugs@FDA
Most recent submissions on application 205598.
Type No. Action Status Date Review
Supplement 5 Efficacy Approved July 23, 2026 Priority
Supplement 3 Labeling Approved November 27, 2019 Standard
Original application 1 Type 1 - New Molecular Entity Approved December 20, 2017 Standard

Review documents

  • 0 · Supplement · July 30, 2026
  • 0 · Supplement · July 27, 2026
  • 0 · Supplement · December 6, 2019
  • 0 · Original application · January 31, 2018
  • 0 · Original application · December 27, 2017
  • 0 · Original application · December 21, 2017

Prescribing information

Source: openFDA Drug Labeling

Reproduced verbatim from the Structured Product Labeling submitted to the FDA (effective 20260218). This is the manufacturer's labelling text, not a summary and not advice.

HUMAN PRESCRIPTION DRUG · 20260218 HUMAN PRESCRIPTION DRUG · 20210130

Indications and Usage

openFDA Drug Labeling

1 INDICATIONS AND USAGE MACRILEN is indicated for the diagnosis of adult growth hormone deficiency (AGHD). MACRILEN is a growth hormone (GH) secretagogue receptor agonist indicated for the diagnosis of adult growth hormone deficiency ( 1 ). Limitations of Use : The safety and diagnostic performance has not been established for subjects with BMI > 40kg/m 2 ( 1 ). Limitations of Use The safety and diagnostic performance of MACRILEN have not been established for subjects with a body mass index (BMI) > 40 kg/m 2 .

Dosage and Administration

openFDA Drug Labeling

2 DOSAGE AND ADMINISTRATION • Recommended dose is 0.5 mg/kg as a single oral dose, after fasting for at least 8 hours ( 2.1 ). • See Full Prescribing Information for important preparation and administration instructions ( 2.3 ). • Discontinue therapy with strong CYP3A4 inducers, growth hormones and drugs that affect GH release for an adequate length of time before administering MACRILEN ( 2.2 ). • Adequately replace other hormone deficiencies before administering MACRILEN ( 2.2 ). 2.1 Recommended Dose The recommended dose is a single oral dose of 0.5 mg/kg of macimorelin. The dose is administered as a reconstituted solution [see Dosage and Administration ( 2.3 )] in patients fasted for at least 8 hours. 2.2 Important Recommendations Before MACRILEN Use • Discontinue strong CYP3A4 inducers prior to MACRILEN use [see Warning and Precautions ( 5.2 ) and Drug Interactions ( 7.2 )]. • Discontinue growth hormone (GH) therapy at least one week before administering MACRILEN [see Drug Interactions ( 7.3 )] . • Avoid the use of MACRILEN with drugs known to affect pituitary GH secretion [see Drug Interactions ( 7.3 )] . • For patients with deficiencies in sex hormones, thyroid hormone and/or glucocorticoid, adequately replace each of the missing hormones before administering MACRILEN. • Ensure that the patient has fasted for at least 8 hours before MACRILEN use. 2.3 Directions for Preparation and Administration Prepare and administer by a healthcare professional exactly as follows. Prepare the MACRILEN solution: a. Weigh the patient in kilograms (i.e., kg) . b. Determine the number of MACRILEN pouches needed to prepare the dose: i. For a patient weighing up to 120 kg, use 1 pouch. ii. For a patient weighing more than 120 kg, use 2 pouches. c. Use a glass or transparent plastic container with graduation in milliliters (i.e., mL) to dissolve the entire contents of the pouch(es) in the appropriate volume of water. i. For 1 pouch dissolve in 120 mL of water (corresponds to 60 mg/120 mL). ii. For 2 pouches dissolve in 240 mL of water (corresponds to 120 mg/240 mL). d. Stir the MACRILEN solution gently for about 2 to 3 minutes (a small amount of un-dissolved particles will remain). The solution will have a final concentration of 0.5 mg/mL . e. Use the MACRILEN solution within 30 minutes after preparation. f. Discard any unused MACRILEN solution. Determine the volume of MACRILEN solution needed for the test: g. Determine the recommended dose to be administered by multiplying the patient weight in kilogram by 0.5 mg/kg. For example, a 70 kg patient will need a 35 mg dose. h. Determine the volume of prepared MACRILEN solution to be administered by dividing the recommended dose by 0.5 mg/mL. For example, a patient requiring a dose of 35 mg will need 70 mL of reconstituted MACRILEN solution. i. Use a syringe (without a needle) with graduations in mL to measure the exact volume of MACRILEN solution to be administered and transfer the required volume of MACRILEN solution into a drinking glass. Administer the MACRILEN solution and perform the test: j. Have the patient being tested drink the entire volume of MACRILEN solution in the drinking glass (i.e., the dose) within 30 seconds . k. Observe the patient being tested per routine for the duration of the test. l. Draw venous blood samples for GH determination at 30 minutes, 45 minutes, 60 minutes and 90 minutes after administration of MACRILEN. m. Prepare serum samples and send to a laboratory for growth hormone determinations. n. o. p. q. r. s. t. u. v. 2.4 Interpretation of MACRILEN Test Results Clinical studies have established that a maximally stimulated serum GH level of less than 2.8 ng/mL (i.e., at the 30, 45, 60 and 90 minute timepoints) following MACRILEN administration confirms the presence of adult growth hormone deficiency.

Dosage Forms and Strengths

openFDA Drug Labeling

3 DOSAGE FORMS AND STRENGTHS For oral solution: 60 mg white to off-white granules in a pouch for reconstitution in 120 mL of water, resulting in a solution of 0.5 mg/mL of macimorelin. For oral solution: 60 mg ( 3 )

Contraindications

openFDA Drug Labeling

4 CONTRAINDICATIONS None None ( 4 )

Warnings and Cautions

openFDA Drug Labeling

5 WARNINGS AND PRECAUTIONS • QT Prolongation: QT prolongation can lead to development of torsade de pointes-type ventricular tachycardia. Avoid the concomitant use of MACRILEN with drugs that are known to prolong QT interval ( 5.1 , 7.1 ). • Potential for False Positive Test Results with Use of Strong CYP3A4 Inducers: Discontinue and washout strong CYP3A4 inducers before testing ( 5.2 , 7.2 ). • Potential for False Negative Test Results in Recent Onset Hypothalamic Disease: Consider repeat testing if indicated ( 5.3 ). 5.1 QT Prolongation MACRILEN causes an increase of about 11 msec in the corrected QT (QTc) interval [see Clinical Pharmacology ( 12.2 )] . QT prolongation can lead to development of torsade de pointes-type ventricular tachycardia with the risk increasing as the degree of prolongation increases. The concomitant use of MACRILEN with drugs that are known to prolong the QT interval should be avoided [see Dosage and Administration ( 2.2 ) and Drug Interactions ( 7.1 )] . 5.2 Potential for False Positive Test Results with Use of Strong CYP3A4 Inducers Concomitant use of strong CYP3A4 inducers with MACRILEN can decrease macimorelin plasma levels significantly and thereby lead to a false positive result [see Drug Interactions ( 7.2 )] . Strong CYP3A4 inducers should be discontinued and enough time should be given to allow washout of CYP3A4 inducers prior to test administration [see Dosage and Administration ( 2.2 )]. 5.3 Potential for False Negative Test Results in Recent Onset Hypothalamic Disease Adult growth hormone (GH) deficiency caused by a hypothalamic lesion may not be detected early in the disease process. Macimorelin acts downstream from the hypothalamus and macimorelin stimulated release of stored GH reserves from the anterior pituitary could produce a false negative result early when the lesion involves the hypothalamus. Repeat testing may be warranted in this situation.

Adverse Reactions

openFDA Drug Labeling

6 ADVERSE REACTIONS to report suspected adverse reactions 1-800-332-1088 to report suspected adverse reactions , contact Aeterna Zentaris GmbH at 1-843-900-2332, or FDA at 1‐800-332-1088 or www.fda.gov/medwatch. to report suspected adverse reactions 1-800-332-1088 to report suspected adverse reactions , contact Aeterna Zentaris GmbH at 1-843-900-2332, or FDA at 1‐800-332-1088 or www.fda.gov/medwatch. The most common adverse reactions were dysgeusia, dizziness, headache, fatigue, nausea, hunger, diarrhea, upper respiratory tract infection, feeling hot, hyperhidrosis, nasopharyngitis, and sinus bradycardia ( 6.1 ). 6.1 Clinical Studies Experience to report suspected adverse reactions 1-800-332-1088 to report suspected adverse reactions , contact Aeterna Zentaris GmbH at 1-843-900-2332, or FDA at 1‐800-332-1088 or www.fda.gov/medwatch. Because clinical trials are conducted under widely varying conditions, adverse reaction rates observed in the clinical trials of a drug cannot be directly compared to rates in the clinical trial of another drug and may not reflect the rates observed in practice. The data in Table 1 are derived from an open-label, randomized, cross-over study that compared the diagnostic performance of MACRILEN to the insulin tolerance test (ITT) for the diagnosis of adult growth hormone deficiency [see Clinical Studies ( 14 )]. A total of 154 subjects with a high to low pre-test probability of having adult growth hormone deficiency received a single oral dose of 0.5 mg/kg MACRILEN. Out of 154 subjects, 58% were male, 42% female, and 86% of white origin. Median values were for age 41 years (range: 18 – 66 years) and body mass index was 27.5 kg/m 2 (range: 16 – 40 kg/m 2 ). Common adverse reactions presented in Table 1 were adverse reactions that were not present at baseline and occurred during MACRILEN dosing in at least two individuals. Table 1: Common Adverse Reactions Reported in at Least Two Individuals Dosed with MACRILEN in an Open-Label Study Number of Subjects (n = 154) Proportion of Subjects (%) Dysgeusia 7 4.5 Dizziness 6 3.9 Headache 6 3.9 Fatigue 6 3.9 Nausea 5 3.2 Hunger 5 3.2 Diarrhea 3 1.9 Upper respiratory tract infection 3 1.9 Feeling hot 2 1.3 Hyperhidrosis 2 1.3 Nasopharyngitis 2 1.3 Sinus bradycardia 2 1.3 The safety of Macrilen was evaluated in 126 pediatric patients. The overall safety profile in the pediatric population was consistent with that observed in adults.

Drug Interactions

openFDA Drug Labeling

7 DRUG INTERACTIONS 7.1 Drugs that Prolong QT Interval Co-administration of MACRILEN with drugs that prolong the QT interval (such as antipsychotic medications (e.g., chlorpromazine, haloperidol, thioridazine, ziprasidone), antibiotics (e.g., moxifloxacin), Class 1A (e.g., quinidine, procainamide) and Class III (e.g., amiodarone, sotalol) antiarrhythmic medications or any other medications known to prolong the QT interval) may lead to development of torsade de pointes-type ventricular tachycardia. Avoid concomitant use of MACRILEN with drugs that prolong the QT interval. Sufficient washout time of drugs that are known to prolong the QT interval prior to administration of MACRILEN is recommended [see Dosage and Administration ( 2.2 ) and Warnings and Precautions ( 5.1 )] . 7.2 Cytochrome P450 (CYP) 3A4 Inducers Co-administration of a strong CYP3A4 inducer with MACRILEN (e.g., carbamazepine, enzalutamide, mitotane, phenytoin, rifampin, St. John's wort, bosentan, efavirenz, etravirine, modafinil, armodafinil, rufinamide) may reduce the plasma macimorelin concentrations and may lead to false positive test results. Discontinue strong CYP3A4 inducers prior to MACRILEN use. Sufficient washout time of strong CYP3A4 inducers prior to administration of MACRILEN is recommended [see Dosage and Administration ( 2.2 ) and Warnings and Precautions ( 5.2 )] . 7.3 Drugs Affecting Growth Hormone Release The following drugs may impact the accuracy of the MACRILEN diagnostic test. Avoid concomitant use of MACRILEN with the following [see Dosage and Administration ( 2.2 )] : • Drugs that directly affect the pituitary secretion of growth hormone (such as somatostatin, insulin, glucocorticoids, and cyclooxygenase inhibitors such as aspirin or indomethacin). • Drugs that may transiently elevate growth hormone concentrations (such as clonidine, levodopa, and insulin). • Drugs that may blunt the growth hormone response to MACRILEN (such as muscarinic antagonists: atropine, anti-thyroid medication: propylthiouracil, and growth hormone products). Discontinue growth hormone products at least one week before administering the MACRILEN diagnostic test. Sufficient washout time of drugs affecting growth hormone release prior to administration of MACRILEN is recommended.

Use in Specific Populations

openFDA Drug Labeling

8 USE IN SPECIFIC POPULATIONS 8.1 Pregnancy Risk summary There are no available data with MACRILEN use in pregnant women to inform a drug associated risk for adverse developmental outcomes. Animal reproduction studies have not been conducted with MACRILEN. MACRILEN is indicated as a single dose which limits the risk of adverse developmental outcomes from exposure to MACRILEN. The estimated background risk of major birth defects and miscarriage for the indicated populations is unknown. All pregnancies have a background risk of birth defect, loss, or other adverse outcomes. In the U.S. general population, the estimated background risk of major birth defects and miscarriage in clinically recognized pregnancies is 2 – 4% and 15 – 20%, respectively. 8.2 Lactation Risk Summary There are no data on the presence of macimorelin in human or animal milk, the effects on the breastfed infant or the effects on milk production. The lack of clinical data during lactation precludes a clear determination of the risk of MACRILEN to an infant during lactation; therefore, the developmental and health benefits of breastfeeding should be considered along with the mother’s clinical need for MACRILEN and any potential adverse effects on the breastfed infant from MACRILEN or the underlying maternal condition. 8.4 Pediatric Use The safety and efficacy of MACRILEN in pediatric patients have not been established. The use of MACRILEN for the diagnosis of Growth Hormone Deficiency (GHD) was evaluated in two open-label studies in pediatric patients aged 3 to 17 years of age. Study 1 (Phase 2) was an open-label, group comparison, dose-escalation single dose escalation study in 24 pediatric patients with suspected GHD. No serious adverse events (SAEs) and no adverse events (AEs) were associated with the macimorelin growth hormone stimulation test (GHST). The study demonstrated a dose-dependent increase in macimorelin exposure and growth hormone (GH) stimulation. Study 2 (Phase 3) was a multicenter, open-label, randomized, crossover study in 102 pediatric patients with suspected GHD. Patients received a single oral dose of MACRILEN on two different occasions, compared to two standard growth hormone stimulation tests (arginine and clonidine). The primary efficacy endpoint was the area under the receiver operating characteristic (ROC) curve (AUC) assessing the diagnostic accuracy of MACRILEN compared to the adjudicated GHD status. The study failed to meet its primary endpoint; the lower bound of the 97.5% confidence interval for the ROC AUC was 0.66, which did not meet the pre-specified threshold of >0.70. Diagnostic performance (sensitivity and specificity) was evaluated against a cut-off point of 25.59 ng/mL, which was derived from the study data. Using this cut-off, sensitivity was 78.6% (95% CI: 63.2, 89.7) and specificity was 67.9% (95% CI: 53.7, 80.1). These results did not meet the pre-specified success criteria. An appropriate diagnostic cut-off point could not be established to consistently distinguish between GHD and non-GHD patients in the pediatric population. 8.5 Geriatric Use Growth hormone secretion normally decreases with age. Therefore, elderly subjects might require a lower cut-off point for diagnosis of adult growth hormone deficiency. Clinical studies of MACRILEN did not include a sufficient number of subjects aged 65 and over to determine whether elderly patients respond differently from younger subjects.

Mechanism of Action

openFDA Drug Labeling

12.1 Mechanism of Action Macimorelin stimulates GH release by activating growth hormone secretagogue receptors present in the pituitary and hypothalamus.

Description

openFDA Drug Labeling

11 DESCRIPTION MACRILEN for oral solution is macimorelin acetate, a synthetic growth hormone secretagogue receptor agonist. Macimorelin acetate is described chemically as D-Tryptophanamide, 2-methylalanyl-N-[(1R)-1-(formylamino)-2-(1H-indol-3-yl)ethyl]-acetate. The molecular formula for macimorelin acetate is C 28 H 34 N 6 O 5 with a molecular weight of 534.6 g/mol. Figure 1: Chemical structure of macimorelin acetate Each aluminum pouch of MACRILEN contains 60 mg of macimorelin, equivalent to 68 mg of macimorelin acetate, and the following inactive ingredients: lactose monohydrate, crospovidone, sodium stearyl fumarate, saccharin sodium and colloidal silicon dioxide. Figure 1

10 OVERDOSAGE In the event of an overdose, symptomatic and supportive measures should be employed.

How Supplied / Storage and Handling

openFDA Drug Labeling

16 HOW SUPPLIED/STORAGE AND HANDLING MACRILEN 60 mg is supplied as white to off-white granules in an aluminum pouch. Each pouch contains 60 mg macimorelin (equivalent to 68 mg macimorelin acetate) that when reconstituted with 120 mL of water provides a 60 mg/120 mL (0.5 mg/mL) macimorelin solution. MACRILEN is available in boxes containing 1 pouch per box (NDC 0169-1401-01). Before administration, MACRILEN for oral solution must be reconstituted by a healthcare professional [see Dosage and Administration ( 2.3 )]. Store pouches under refrigeration at 2-8°C (36-46°F). The solution must be used within 30 minutes after preparation. Discard unused portion.

Adverse event reports

Source: openFDA FAERS
5
FAERS reports mentioning this drug
as of 2026-09-25T03:42:24+00:00
A report count is not a risk measure. FAERS accepts voluntary and mandatory reports without establishing causation, and reporting is influenced by how widely a drug is used, how long it has been marketed, and media attention. FDA states that reports “do not prove that the drug caused the event”. Compare rates, not totals.

Attributed to this product's most-reported active ingredient: MACIMORELIN. Combination products with more than six active ingredients are not attributed, because a report count summed across a long ingredient list measures the list, not the medicine.

Packaging and NDCs

Source: NDC Directory
Every National Drug Code package associated with this medication. The NDC is the identifier used for dispensing, billing and pharmacovigilance in the United States.
Package NDC Product NDC Labeler Description Marketing start
58844-130-01 58844-130 Aeterna Zentaris GmbH 1 POUCH in 1 CARTON (58844-130-01) / 60 mg in 1 POUCH January 29, 2018
0169-1401-01 0169-1401 Novo Nordisk 1 POUCH in 1 CARTON (0169-1401-01) / 60 mg in 1 POUCH January 31, 2022
58844-130 58844-130 Aeterna Zentaris GmbH — January 29, 2018
0169-1401 0169-1401 Novo Nordisk — January 31, 2022

Sources for this page

Every dataset that contributed a fact to this page.
Dataset Agency Used for
NDC Directory FDA Identity, ingredients, strengths, forms, routes, labelers, packages
Drugs@FDA FDA Application, sponsor, submissions, review documents, marketing status
Orange Book FDA Therapeutic equivalence codes, reference drug flags, patents, exclusivity
Drug Labeling FDA / NLM Prescribing information reproduced above
FAERS FDA Adverse event report counts

Generated September 25, 2026 · 12 sections on this page.