Somatrogon-ghla (Monograph)

Drug class: Pituitary

Medically reviewed by Drugs.com on Jun 10, 2024. Written by ASHP.

Introduction

Human growth hormone analog.

Uses for Somatrogon-ghla

Growth Hormone Deficiency

Used for treatment of growth failure due to inadequate secretion of endogenous growth hormone in pediatric patients ≥3 years of age (designated an orphan drug by FDA for this use).

The Pediatric Endocrine Society guideline recommends the use of growth hormone to normalize adult height and avoid extreme shortness in children and adolescents with growth hormone deficiency. Specific place in therapy of somatrogon-ghla not yet established.

Somatrogon-ghla Dosage and Administration

General

Pretreatment Screening

Perform a fundoscopic examination prior to therapy initiation to exclude preexisting papilledema.

Patient Monitoring

Monitor glucose levels periodically in all patients, particularly those with risk factors for diabetes mellitus (e.g., obesity, Turner syndrome, family history of diabetes mellitus), preexisting type 1 or type 2 diabetes mellitus, or pre-diabetes.
Perform periodic fundoscopic examinations during treatment to identify intracranial hypertension.
Monitor for development or progression of scoliosis.
Monitor for reduced serum cortisol and/or need for increase in stress or maintenance doses of glucocorticoids in patients with known hypoadrenalism.
Perform periodic thyroid function testing during somatrogon-ghla therapy.
Monitor patients if abnormal laboratory testing (increased serum levels of phosphorus, alkaline phosphatase, and parathyroid hormone) is detected during somatrogon-ghla therapy.
Monitor for tumor progression or recurrence in patients with a history of growth hormone deficiency secondary to an intracranial neoplasm treated with radiation to the brain/head.
Carefully monitor for the development of neoplasms in children with certain rare genetic causes of short stature. Monitor for increased growth or potential malignant changes of preexisting nevi.
Evaluate for slipped capital femoral epiphysis in patients who develop a limp or complain of persistent hip or knee pain.

Other General Considerations

Somatrogon-ghla treatment should be supervised by a prescriber experienced in the management of pediatric patients with growth hormone deficiency.
In patients with malignancy, confirm that preexisting neoplasms are inactive and that neoplasm treatment has been completed prior to initiating somatrogon-ghla.

Administration

Sub-Q

Administer by sub-Q injection once weekly, on the same day each week, at any time of day. Administer in abdomen, thighs, buttocks, or upper arms. Rotate injection site each week; use new needle with each injection. If more than 1 injection required to administer a complete dose, administer each injection at a different injection site.

Supplied as a single-patient-use disposable prefilled pen containing 24 mg/1.2 mL (20 mg/mL) or 60 mg/1.2 mL (50 mg/mL). The 24 mg/1.2 mL and 60 mg/1.2 mL prefilled pens deliver a dose in 0.2 mg and 0.5 mg increments, respectively.

Treatment should be supervised by a healthcare provider experienced in the diagnosis and management of pediatric patients ≥3 years of age with growth failure due to growth hormone deficiency.

Day of weekly administration can be changed as long as there are ≥3 days between 2 doses. Once new day chosen, continue once weekly dosing.

If switching from daily growth hormone, may initiate somatrogon-ghla the day after last daily injection.

If missed dose, administer somatrogon-ghla as soon as possible within 3 days after missed dose. If >3 days have passed, skip missed dose and administer next dose on regularly scheduled day.

Dosage

Pediatric Patients

Growth Hormone Deficiency

Sub-Q

Children ≥3 years of age: 0.66 mg/kg (based on actual body weight) once weekly. Individualize dosage based on growth response.

Special Populations

Hepatic Impairment

No specific dosage recommendations at this time.

Renal Impairment

No specific dosage recommendations at this time.

Geriatric Patients

No specific dosage recommendations at this time.

Cautions for Somatrogon-ghla

Contraindications

Acute critical illness after open heart surgery, abdominal surgery, or multiple accidental trauma, or those with acute respiratory failure due to risk of increased mortality with somatropin.
Hypersensitivity to somatrogon-ghla or any excipient in the product.
Closed epiphyses.
Active malignancy.
Active proliferative or severe non-proliferative diabetic retinopathy.
Prader-Willi syndrome in patients who are severely obese or have a history of upper airway obstruction or sleep apnea or have severe respiratory impairment due to risk of sudden death.

Warnings/Precautions

Increased Mortality in Patients with Acute Critical Illness

Increased mortality reported in patients with acute respiratory failure or acute critical illness because of complications secondary to open heart surgery, abdominal surgery, or multiple accidental trauma.

Not known if somatrogon-ghla safe to continue in patients who concomitantly develop these conditions.

Severe Hypersensitivity

Severe hypersensitivity reactions (including anaphylaxis and angioedema) reported.

Inform patients and/or caregivers that hypersensitivity reactions can occur and to seek prompt medical care if an allergic reaction occurs.

Increased Risk of Neoplasms

Increased risk of neoplasm progression in active malignancy. Confirm preexisting neoplasms are inactive and that treatment of neoplasm is complete prior to somatrogon-ghla initiation; discontinue somatrogon-ghla if recurrent neoplasm develops.

Childhood cancer survivors who received brain/head radiation for their first neoplasm and who developed subsequent growth hormone deficiency at increased risk for a second neoplasm (particularly intracranial tumors) with somatrogon-ghla therapy. Because of risks of tumor progression and recurrence, monitor patients with a history of growth hormone decifiency secondary to an intracranial neoplasm during somatrogon-ghla therapy.

Consider risks/benefits of somatrogon-ghla initiation in children with certain genetic causes of short stature; if somatrogon-ghla initiated, carefully monitor for neoplasm development.

Monitor carefully for increased growth or possible malignant changes in preexisting nevi. Advise patients and/or caregivers to report significant behavioral changes, onset of headaches, visual disturbances, and/or changes in skin pigmentation or in appearance of preexisting nevi.

Glucose Tolerance and Diabetes Mellitus

Can decrease insulin sensitivity (particularly at higher dosages); new onset of type 2 diabetes mellitus reported. Potential for symptomatic worsening of glycemic control In patients with undiagnosed pre-diabetes or diabetes mellitus.

Monitor glucose levels periodically in all patients, particularly those with risk factors for diabetes mellitus (e.g., obesity, Turner syndrome, family history of diabetes mellitus). Closely monitor patients with preexisting type 1 or type 2 diabetes mellitus or pre-diabetes. Concomitant antihyperglycemic agents may require dosage adjustment when starting somatrogon-ghla.

Intracranial Hypertension

Cases of intracranial hypertension with papilledema, visual changes, headache, nausea, and/or vomiting reported.

Perform a fundoscopic examination prior to somatrogon-ghla initiation to exclude preexisting papilledema; periodic fundoscopic examination recommended thereafter. If papilledema identified prior to somatrogon-ghla initiation, evaluate underlying etiology and treat underlying cause prior to starting somatrogon-ghla.

Temporarily discontinue somatrogon-ghla in patients with clinical or fundoscopic evidence of intracranial hypertension. If intracranial hypertension confirmed, restart somatrogon-ghla at a lower dosage after resolution of intracranial hypertension-associated signs and symptoms.

Fluid Retention

Fluid retention, including edema and nerve compression syndromes (e.g., carpal tunnel syndrome/paresthesia), can occur; usually transient and dose-related.

Hypoadrenalism

Potential increased risk for reduced plasma cortisol levels and/or unmasking of central (secondary) hypoadrenalism in patients who have or are at risk for pituitary hormone deficiency(s).

Increased maintenance or stress doses of glucocorticoids may be required after initiating somatrogon-ghla in patients with hypoadrenalism. Monitor for reduced serum cortisol levels and/or potential need for glucocorticoid dosage increases in patients with known hypoadrenalism.

Hypothyroidism

Undiagnosed or untreated hypothyroidism may prevent optimal therapy response; central (secondary) hypothyroidism may first become evident or worsen during treatment.

Perform periodic thyroid function testing; initiate and/or adjust thyroid hormone replacement therapy when indicated.

Slipped Capital Femoral Epiphysis

Possible increased frequency of occurence in patients with rapid growth.

Evaluate patients with onset of limp or complaints of persistent knee or hip pain.

Progression of Preexisting Scoliosis

Possible progression of preexisting scoliosis in patients who experience rapid growth.

Monitor for disease progression in patients with history of scoliosis.

Pancreatitis

Pancreatitis reported; consider diagnosis in patients who develop persistent severe abdominal pain.

Lipoatrophy

Can occur from continued administration at same injection site over long period of time.

Rotate injection sites to reduce risk of lipoatrophy.

Sudden Death in Pediatric Patients with Prader-Willi Syndrome

Cases of sudden death reported in patients with Prader-Willi syndrome with ≥1 of the following risk factors: severe obesity, history of upper airway obstruction or sleep apnea, unidentified respiratory infection. Males with ≥1 of these risk factors may be at increased risk compared to females.

Not indicated for use in pediatric patients with growth failure secondary to Prader-Willi syndrome.

Laboratory Testing

Possible increased serum levels of phosphorus, alkaline phosphatase, and parathyroid hormone.

Monitor if abnormal laboratory testing detected.

Immunogenicity

Potential for immunogenicity. Anti-drug antibodies (persisting in most cases) observed in patients treated with somatrogan-ghla; neutralizing antibodies (transient in all cases) also observed.

Anti-drug antibodies (including neutralizing-antibodies) did not appear to have a clinically important impact on somatrogon-ghla safety or effectiveness; no apparent effect on growth observed.

Population pharmacokinetic analysis found 26% decrease in drug clearance in patients who tested positive for anti-drug antibodies; this change not considered clinically important.

Specific Populations

Pregnancy

No data available in pregnancy to evaluate for a drug-associated risk of major birth defects, miscarriage, or adverse maternal or fetal outcomes.

Lactation

Not known whether present in human or animal milk. Effects on breast-fed infant or on milk production also unknown.

Consider developmental and health benefits of breast-feeding along with mother’s clinical need for somatrogon-ghla and any potential adverse effects on breast-fed infant from drug or from underlying maternal condition.

Females and Males of Reproductive Potential

Possible interference with human chorionic gonadotropin (hCG) blood and urine pregnancy tests in patients receiving somatrogon-ghla.

Use alternative methods of pregnancy testing (i.e., not reliant on hCG).

Pediatric Use

Safety and efficacy established for treatment of growth failure due to inadequate endogenous growth hormone secretion in pediatric patients ≥3 years of age.

Risks of growth hormone use in pediatric patients: increased risk of second neoplasm in cancer survivors with previous radiation treatment to the brain and/or head, slipped capital femoral epiphysis, progression of preexisting scoliosis, pancreatitis, and sudden death in patients with Prader-Willi Syndrome. Not indicated for use in pediatric patients with growth failure secondary to Prader-Willi syndrome.

Geriatric Use

Not studied.

Hepatic Impairment

Not studied.

Renal Impairment

Not studied.

Common Adverse Effects

Adverse effects (≥5%): injection site reactions, nasopharyngitis, headache, pyrexia, anemia, cough, vomiting, hypothyroidism, abdominal pain, rash, oropharyngeal pain.

Drug Interactions

Drugs Metabolized by Hepatic Microsomal Enzymes

May alter clearance of drugs metabolized by CYP450 isoenzymes.

Monitor carefully when drugs metabolized by CYP450 isoenzymes are used concomitantly with somatrogon-ghla.

Specific Drugs

Drug

Interaction

Comment

Antihyperglycemic agents

Somatrogon-ghla may decrease insulin sensitivity, particularly at higher dosages

Dosage adjustment of insulin and/or other antihyperglycemic agents may be required

Corticosteroids

Replacement corticosteroids: Somatrogon-ghla inhibits microsomal enzyme 11ß-hydroxysteroid dehydrogenase type 1 (11ßHSD-1), which converts cortisone to cortisol (active metabolite). Upon initiation of somatrogon-glha, 11ßHSD-1 may be inhibited, causing reduced plasma cortisol levels. Cortisone acetate and prednisone particularly affected since their conversion to biologically active metabolites depends on 11ßHSD-1 activity

Supraphysiologic corticosteroids: May attenuate growth-promoting effects of somatrogon-ghla

Replacement corticosteroids: Upon somatrogon-glha initiation, increased maintenance or stress corticosteroid dosing may be required

Supraphysiologic corticosteroids: Adjust corticosteroid replacement dosing carefully to avoid hypoadrenalism and inhibitory effects on growth

Estrogen (oral)

Oral estrogens may reduce insulin-like growth factor (IGF-1) response to somatrogon-ghla

With concomitant oral estrogen therapy, higher doses of somatrogon-ghla may be required

Somatrogon-ghla Pharmacokinetics

Absorption

Bioavailability

Dose-proportional increases in exposure for doses of 0.25 mg/kg weekly, 0.48 mg/kg weekly, and 0.66 mg/kg weekly in patients 3–15.5 years of age with growth hormone deficiency. No accumulation after once-weekly administration.

Following sub-Q administration, serum concentrations peaked at 6–25 hours (median: 11 hours) after dosing.

Onset

Peak plasma levels of insulin-like growth factor (IGF-1) attained approximately 2 days following sub-Q administration; mean weekly IGF-1 occurs approximately 4 days post-dose.

Special Populations

Exposure decreases with increasing body weight; however, dose of 0.66 mg/kg once weekly maintains adequate systemic exposure over weight range of 10–54 kg.

Distribution

Extent

Not known if present in human milk.

Elimination

Metabolism

Classical protein catabolism with subsequent recovery of amino acids and return to systemic circulation.

Drug present in circulation for about 8 days after last dose.

Half-life

37.7 hours.

Special Populations

Age, sex, race, and ethnicity have no clinically important effects on somatrogon-ghla pharmacokinetics.

Stability

Storage

Parenteral

Injection, for sub-Q use

Before first use: Store at 2–8ºC in original carton to protect from light.

After first use: Store at 2–8ºC between each use, for up to 28 days. Do not use prefilled pen >28 days after first use.

Do not freeze or shake; do not use if previously frozen. Do not expose to heat; store away from direct sunlight. Store prefilled pen without an injection needle attached.

Actions

Human growth hormone analog; fusion protein produced in Chinese Hamster Ovary cells by recombinant DNA technology.
Binds to growth hormone receptor, initiating a signal transduction cascade that results in changes in growth and metabolism.
Activates STAT5b signaling pathway to increase plasma concentrations of insulin-like growth factor (IGF-1).
Growth hormone and IGF-1 stimulate metabolic changes, linear growth, and enhance growth velocity in pediatric patients with growth hormone deficiency.

Advice to Patients

Advise patients and/or caregivers to read the FDA-approved Patient Information and Instructions for Use.
Advise patients and caregivers that serious systemic hypersensitivity reactions, including anaphylaxis and angioedema, can occur with somatrogon-ghla, and to seek immediate medical attention if an allergic reaction occurs.
Advise childhood cancer survivors and caregivers that prior radiation to the head increases the risk of secondary neoplasms, and as a precautionary measure, monitoring is needed for recurrent neoplasms. Advise patients and caregivers to report significant changes in skin pigmentation or changes in the appearance of preexisting nevi.
Advise patients and caregivers that patients with glucose intolerance or with risk factors for diabetes may require blood glucose monitoring during treatment with somatrogon-ghla, because of the risk of new onset of insulin resistance and hyperglycemia.
Advise patients and caregivers to report any visual changes, headaches, and nausea and/or vomiting to their clinician.
Advise patients and caregivers that fluid retention can develop during treatment with somatrogon-ghla. Inform patients of the signs and symptoms of fluid retention, such as edema, arthralgia, myalgia, and nerve compression syndromes (including carpal tunnel syndrome/paresthesia), and to report to their clinician if any of these occur during treatment.
Advise caregivers and patients who have or are at risk for corticotropin deficiency that hypoadrenalism may develop during treatment with somatrogon-ghla. Advise patients to report extreme fatigue, dizziness, weakness, vomiting, dehydration or weight loss to their clinician while receiving somatrogon-ghla.
Advise patients and caregivers that undiagnosed or untreated hypothyroidism can result in a suboptimal response to somatrogon-ghla. Inform patients and caregivers that periodic thyroid function testing may be required during treatment with somatrogon-ghla.
Advise patients and caregivers that pancreatitis may develop during treatment with somatrogon-ghla, and to report new onset persistent, severe abdominal pain to their clinician.
Advise patients and caregivers to rotate injection sites when administering somatrogon-ghla, since lipoatrophy can occur when somatrogon-ghla is administered subcutaneously at the same site over extended periods of time.
Advise patients to inform their clinician of existing or contemplated concomitant therapy, including prescription and OTC drugs and dietary or herbal supplements, as well as any concomitant illnesses.
Advise women to inform their clinician if they are or plan to become pregnant or plan to breast-feed. Advise patients to use testing methods that are not reliant on human chorionic gonadotropin to determine pregnancy.
Inform patients of other important precautionary information.

Additional Information

The American Society of Health-System Pharmacists, Inc. represents that the information provided in the accompanying monograph was formulated with a reasonable standard of care, and in conformity with professional standards in the field. Readers are advised that decisions regarding use of drugs are complex medical decisions requiring the independent, informed decision of an appropriate health care professional, and that the information contained in the monograph is provided for informational purposes only. The manufacturer’s labeling should be consulted for more detailed information. The American Society of Health-System Pharmacists, Inc. does not endorse or recommend the use of any drug. The information contained in the monograph is not a substitute for medical care.

Preparations

Excipients in commercially available drug preparations may have clinically important effects in some individuals; consult specific product labeling for details.

Please refer to the ASHP Drug Shortages Resource Center for information on shortages of one or more of these preparations.

Somatrogon-ghla
Routes	Dosage Forms	Strengths	Brand Names	Manufacturer
Parenteral	Injection, for subcutaneous use	24 mg/1.2 mL (20 mg/mL)	Ngenla (available in a single-patient-use prefilled pen)	Pfizer Laboratories
		60 mg/1.2 mL (50 mg/mL)	Ngenla (available in a single-patient-use prefilled pen)	Pfizer Laboratories