Pediatric Patients
Genotropin (somatropin [rDNA origin] for injection) is indicated for the treatment of pediatric patients who have growth failure due to an inadequate secretion of endogenous growth hormone.
Genotropin (somatropin [rDNA origin] for injection) is indicated for the treatment of pediatric patients who have growth failure due to Prader-Willi syndrome (PWS). The diagnosis of PWS should be confirmed by appropriate genetic testing (see CONTRAINDICATIONS).
Genotropin (somatropin [rDNA origin] for injection) is indicated for the treatment of growth failure in children born small for gestational age (SGA) who fail to manifest catch-up growth by age 2 years.
Genotropin (somatropin [rDNA origin] for injection) is indicated for the treatment of growth failure associated with Turner syndrome.
Genotropin (somatropin [rDNA origin] for injection) is indicated for the treatment of idiopathic short stature (ISS), also called non-growth hormone-deficient short stature, defined by height standard deviation score (SDS) ≤-2.25, and associated with growth rates unlikely to permit attainment of adult height in the normal range, in pediatric patients whose epiphyses are not closed and for whom diagnostic evaluation excludes other causes associated with short stature that should be observed or treated by other means.
Adult Patients
Genotropin (somatropin [rDNA origin] for injection) is indicated for replacement of endogenous growth hormone in adults with growth hormone deficiency who meet either of the following two criteria:
Adult Onset (AO): Patients who have growth hormone deficiency, either alone or associated with multiple hormone deficiencies (hypopituitarism), as a result of pituitary disease, hypothalamic disease, surgery, radiation therapy, or trauma; or
Childhood Onset (CO): Patients who were growth hormone deficient during childhood as a result of congenital, genetic, acquired, or idiopathic causes.
Patients who were treated with somatropin for growth hormone deficiency in childhood and whose epiphyses are closed should be reevaluated before continuation of somatropin therapy at the reduced dose level recommended for growth hormone deficient adults. According to current standards, confirmation of the diagnosis of adult growth hormone deficiency in both groups involves an appropriate growth hormone provocative test with two exceptions: (1) patients with multiple other pituitary hormone deficiencies due to organic disease; and (2) patients with congenital/genetic growth hormone deficiency.
Genotropin Dosage and Administration
The weekly dose should be divided into 6 or 7 subcutaneous injections. Genotropin must not be injected intravenously.
Therapy with Genotropin should be supervised by a physician who is experienced in the diagnosis and management of pediatric patients with growth failure associated with growth hormone deficiency (GHD), Prader-Willi syndrome (PWS), Turner syndrome (TS), those who were born small for gestational age (SGA) or Idiopathic Short Stature (ISS), and adult patients with either childhood onset or adult onset GHD.
Dosing of Pediatric Patients
General Pediatric Dosing Information
The Genotropin dosage and administration schedule should be individualized based on the growth response of each patient.
Response to somatropin therapy in pediatric patients tends to decrease with time. However, in pediatric patients, the failure to increase growth rate, particularly during the first year of therapy, indicates the need for close assessment of compliance and evaluation for other causes of growth failure, such as hypothyroidism, undernutrition, advanced bone age and antibodies to recombinant human GH (rhGH).
Treatment with Genotropin for short stature should be discontinued when the epiphyses are fused.
Pediatric Growth Hormone Deficiency (GHD)
Generally, a dose of 0.16 to 0.24 mg/kg body weight/week is recommended.
Prader-Willi Syndrome
Generally, a dose of 0.24 mg/kg body weight/week is recommended.
Turner Syndrome
Generally, a dose of 0.33 mg/kg body weight/week is recommended.
Idiopathic Short Stature
Generally, a dose up to 0.47 mg/kg body weight/week is recommended.
Small for Gestational Age
Generally, a dose of up to 0.48 mg/kg body weight/week is recommended.
Dosing of Adult Patients
Adult Growth Hormone Deficiency (GHD)
Either of two approaches to Genotropin dosing may be followed: a non-weight based regimen or a weight based regimen.
Non-weight based — based on published consensus guidelines, a starting dose of approximately 0.2 mg/day (range, 0.15–0.30 mg/day) may be used without consideration of body weight. This dose can be increased gradually every 1–2 months by increments of approximately 0.1–0.2 mg/day, according to individual patient requirements based on the clinical response and serum insulin-like growth factor I (IGF-I) concentrations. The dose should be decreased as necessary on the basis of adverse events and/or serum IGF-I concentrations above the age- and gender-specific normal range. Maintenance dosages vary considerably from person to person, and between male and female patients.
Weight based — based on the dosing regimen used in the original adult GHD registration trials, the recommended dosage at the start of treatment is not more than 0.04 mg/kg/week. The dose may be increased according to individual patient requirements to not more than 0.08 mg/kg/week at 4–8 week intervals. Clinical response, side effects, and determination of age- and gender-adjusted serum IGF-I concentrations should be used as guidance in dose titration.
A lower starting dose and smaller dose increments should be considered for older patients, who are more prone to the adverse effects of somatropin than younger individuals. In addition, obese individuals are more likely to manifest adverse effects when treated with a weight-based regimen. In order to reach the defined treatment goal, estrogen-replete women may need higher doses than men. Oral estrogen administration may increase the dose requirements in women.
Preparation and Administration
The Genotropin 5 and 12 mg cartridges are color-coded to help ensure proper use with the Genotropin Pen delivery device. The 5 mg cartridge has a green tip to match the green pen window on the Pen 5, while the 12 mg cartridge has a purple tip to match the purple pen window on the Pen 12.
Parenteral drug products should always be inspected visually for particulate matter and discoloration prior to administration, whenever solution and container permit. Genotropin MUST NOT BE INJECTED if the solution is cloudy or contains particulate matter. Use it only if it is clear and colorless.
Genotropin may be given in the thigh, buttocks, or abdomen; the site of SC injections should be rotated daily to help prevent lipoatrophy.
Dosage Forms and Strengths
Genotropin lyophilized powder:
- 5 mg two-chamber cartridge (green tip, with preservative)
concentration of 5 mg/mL
- 12 mg two-chamber cartridge (purple tip, with preservative)
concentration of 12 mg/mL
Genotropin MINIQUICK Growth Hormone Delivery Device containing a two-chamber cartridge of Genotropin (without preservative)
- 0.2 mg, 0.4 mg, 0.6 mg, 0.8 mg, 1.0 mg, 1.2 mg, 1.4 mg, 1.6 mg, 1.8 mg, and 2.0 mg
Contraindications
Acute Critical Illness
Treatment with pharmacologic amounts of somatropin is contraindicated in patients with acute critical illness due to complications following open heart surgery, abdominal surgery or multiple accidental trauma, or those with acute respiratory failure. Two placebo-controlled clinical trials in non-growth hormone deficient adult patients (n=522) with these conditions in intensive care units revealed a significant increase in mortality (41.9% vs. 19.3%) among somatropin-treated patients (doses 5.3 – 8 mg/day) compared to those receiving placebo [see Warnings and Precautions (5.1)].
Prader-Willi Syndrome in Children
Somatropin is contraindicated in patients with Prader-Willi syndrome who are severely obese, have a history of upper airway obstruction or sleep apnea, or have severe respiratory impairment. There have been reports of sudden death when somatropin was used in such patients [see Warnings and Precautions (5.2)].
Active Malignancy
In general, somatropin is contraindicated in the presence of active malignancy. Any preexisting malignancy should be inactive and its treatment complete prior to instituting therapy with somatropin. Somatropin should be discontinued if there is evidence of recurrent activity. Since growth hormone deficiency may be an early sign of the presence of a pituitary tumor (or, rarely, other brain tumors), the presence of such tumors should be ruled out prior to initiation of treatment. Somatropin should not be used in patients with any evidence of progression or recurrence of an underlying intracranial tumor.
Diabetic Retinopathy
Somatropin is contraindicated in patients with active proliferative or severe non-proliferative diabetic retinopathy.
Closed Epiphyses
Somatropin should not be used for growth promotion in pediatric patients with closed epiphyses.
Hypersensitivity
Genotropin is contraindicated in patients with a known hypersensitivity to somatropin or any of its excipients. The 5 mg and 12 mg presentations of Genotropin lyophilized powder contain m-cresol as a preservative. These products should not be used by patients with a known sensitivity to this preservative. The Genotropin MINIQUICK presentations are preservative-free (see HOW SUPPLIED). Localized reactions are the most common hypersensitivity reactions.
Warnings and Precautions
Acute Critical Illness
Increased mortality in patients with acute critical illness due to complications following open heart surgery, abdominal surgery or multiple accidental trauma, or those with acute respiratory failure has been reported after treatment with pharmacologic amounts of somatropin [see Contraindications (4.1)]. The safety of continuing somatropin treatment in patients receiving replacement doses for approved indications who concurrently develop these illnesses has not been established. Therefore, the potential benefit of treatment continuation with somatropin in patients having acute critical illnesses should be weighed against the potential risk.
Prader-Willi Syndrome in Children
There have been reports of fatalities after initiating therapy with somatropin in pediatric patients with Prader-Willi syndrome who had one or more of the following risk factors: severe obesity, history of upper airway obstruction or sleep apnea, or unidentified respiratory infection. Male patients with one or more of these factors may be at greater risk than females. Patients with Prader-Willi syndrome should be evaluated for signs of upper airway obstruction and sleep apnea before initiation of treatment with somatropin. If during treatment with somatropin, patients show signs of upper airway obstruction (including onset of or increased snoring) and/or new onset sleep apnea, treatment should be interrupted. All patients with Prader-Willi syndrome treated with somatropin should also have effective weight control and be monitored for signs of respiratory infection, which should be diagnosed as early as possible and treated aggressively [see Contraindications (4.2)].
Neoplasms
Patients with preexisting tumors or growth hormone deficiency secondary to an intracranial lesion should be examined routinely for progression or recurrence of the underlying disease process. In pediatric patients, clinical literature has revealed no relationship between somatropin replacement therapy and central nervous system (CNS) tumor recurrence or new extracranial tumors. However, in childhood cancer survivors, an increased risk of a second neoplasm has been reported in patients treated with somatropin after their first neoplasm. Intracranial tumors, in particular meningiomas, in patients treated with radiation to the head for their first neoplasm, were the most common of these second neoplasms. In adults, it is unknown whether there is any relationship between somatropin replacement therapy and CNS tumor recurrence.
Patients should be monitored carefully for any malignant transformation of skin lesions.
Impaired Glucose Tolerance and Diabetes Mellitus
Treatment with somatropin may decrease insulin sensitivity, particularly at higher doses in susceptible patients. As a result, previously undiagnosed impaired glucose tolerance and overt diabetes mellitus may be unmasked during somatropin treatment. New-onset Type 2 diabetes mellitus has been reported. Therefore, glucose levels should be monitored periodically in all patients treated with somatropin, especially in those with risk factors for diabetes mellitus, such as obesity, Turner syndrome, or a family history of diabetes mellitus. Patients with preexisting type 1 or type 2 diabetes mellitus or impaired glucose tolerance should be monitored closely during somatropin therapy. The doses of antihyperglycemic drugs (i.e., insulin or oral/injectable agents) may require adjustment when somatropin therapy is instituted in these patients.
Intracranial Hypertension
Intracranial hypertension (IH) with papilledema, visual changes, headache, nausea and/or vomiting has been reported in a small number of patients treated with somatropin products. Symptoms usually occurred within the first eight (8) weeks after the initiation of somatropin therapy. In all reported cases, IH-associated signs and symptoms rapidly resolved after cessation of therapy or a reduction of the somatropin dose. Funduscopic examination should be performed routinely before initiating treatment with somatropin to exclude preexisting papilledema, and periodically during the course of somatropin therapy. If papilledema is observed by funduscopy during somatropin treatment, treatment should be stopped. If somatropin-induced IH is diagnosed, treatment with somatropin can be restarted at a lower dose after IH-associated signs and symptoms have resolved. Patients with Turner syndrome and Prader-Willi syndrome may be at increased risk for the development of IH.
Fluid Retention
Fluid retention during somatropin replacement therapy in adults may occur. Clinical manifestations of fluid retention are usually transient and dose dependent.
Hypopituitarism
Patients with hypopituitarism (multiple pituitary hormone deficiencies) should have their other hormonal replacement treatments closely monitored during somatropin treatment.
Hypothyroidism
Undiagnosed/untreated hypothyroidism may prevent an optimal response to somatropin, in particular, the growth response in children. Patients with Turner syndrome have an inherently increased risk of developing autoimmune thyroid disease and primary hypothyroidism. In patients with growth hormone deficiency, central (secondary) hypothyroidism may first become evident or worsen during somatropin treatment. Therefore, patients treated with somatropin should have periodic thyroid function tests and thyroid hormone replacement therapy should be initiated or appropriately adjusted when indicated.
Slipped Capital Femoral Epiphyses in Pediatric Patients
Slipped capital femoral epiphyses may occur more frequently in patients with endocrine disorders (including GHD and Turner syndrome) or in patients undergoing rapid growth. Any pediatric patient with the onset of a limp or complaints of hip or knee pain during somatropin therapy should be carefully evaluated.
Progression of Preexisting Scoliosis in Pediatric Patients
Progression of scoliosis can occur in patients who experience rapid growth. Because somatropin increases growth rate, patients with a history of scoliosis who are treated with somatropin should be monitored for progression of scoliosis. However, somatropin has not been shown to increase the occurrence of scoliosis. Skeletal abnormalities including scoliosis are commonly seen in untreated Turner syndrome patients. Scoliosis is also commonly seen in untreated patients with Prader-Willi syndrome. Physicians should be alert to these abnormalities, which may manifest during somatropin therapy.
Otitis Media and Cardiovascular Disorders in Turner Syndrome
Patients with Turner syndrome should be evaluated carefully for otitis media and other ear disorders since these patients have an increased risk of ear and hearing disorders. Somatropin treatment may increase the occurrence of otitis media in patients with Turner syndrome. In addition, patients with Turner syndrome should be monitored closely for cardiovascular disorders (e.g., stroke, aortic aneurysm/dissection, hypertension) as these patients are also at risk for these conditions.
Local and Systemic Reactions
When somatropin is administered subcutaneously at the same site over a long period of time, tissue atrophy may result. This can be avoided by rotating the injection site [see Dosage and Administration. (2.3) ].
As with any protein, local or systemic allergic reactions may occur. Parents/Patients should be informed that such reactions are possible and that prompt medical attention should be sought if allergic reactions occur.
Laboratory Tests
Serum levels of inorganic phosphorus, alkaline phosphatase, parathyroid hormone (PTH) and IGF-I may increase during somatropin therapy.
Pancreatitis
Cases of pancreatitis have been reported rarely in children and adults receiving somatropin treatment, with some evidence supporting a greater risk in children compared with adults. Published literature indicates that girls who have Turner syndrome may be at greater risk than other somatropin-treated children. Pancreatitis should be considered in any somatropin–treated patient, especially a child, who develops persistent severe abdominal pain.
Adverse Reactions
Most Serious and/or Most Frequently Observed Adverse Reactions
This list presents the most seriousb and/or most frequently observeda adverse reactions during treatment with somatropin:
- b Sudden death in pediatric patients with Prader-Willi syndrome with risk factors including severe obesity, history of upper airway obstruction or sleep apnea and unidentified respiratory infection [see Contraindications (4.2) and Warnings andPrecautions (5.2)]
- b Intracranial tumors, in particular meningiomas, in teenagers/young adults treated with radiation to the head as children for a first neoplasm and somatropin [see Contraindications (4.3) and Warnings and Precautions (5.3)]
- a, b Glucose intolerance including impaired glucose tolerance/impaired fasting glucose as well as overt diabetes mellitus [see Warnings and Precautions (5.4)]
- b Intracranial hypertension [see Warnings and Precautions (5.5)]
- b Significant diabetic retinopathy [see Contraindications (4.4)]
- b Slipped capital femoral epiphysis in pediatric patients [see Warnings and Precautions (5.8)]
- b Progression of preexisting scoliosis in pediatric patients [see Warnings and Precautions (5.9)]
- aFluid retention manifested by edema, arthralgia, myalgia, nerve compression syndromes including carpal tunnel syndrome/paraesthesias [see Warnings and Precautions (5.6)]
- aUnmasking of latent central hypothyroidism [see Warnings and Precautions (5.7)]
- aInjection site reactions/rashes and lipoatrophy (as well as rare generalized hypersensitivity reactions) [see Warnings andPrecautions (5.11)]
- b Pancreatitis [see Warnings and Precautions (5.14)]
Clinical Trials Experience
Because clinical trials are conducted under varying conditions, adverse reaction rates observed during the clinical trials performed with one somatropin formulation cannot always be directly compared to the rates observed during the clinical trials performed with a second somatropin formulation, and may not reflect the adverse reaction rates observed in practice.
Clinical Trials in children with GHD
In clinical studies with Genotropin in pediatric GHD patients, the following events were reported infrequently: injection site reactions, including pain or burning associated with the injection, fibrosis, nodules, rash, inflammation, pigmentation, or bleeding; lipoatrophy; headache; hematuria; hypothyroidism; and mild hyperglycemia.
Clinical Trials in PWS
In two clinical studies with Genotropin in pediatric patients with Prader-Willi syndrome, the following drug-related events were reported: edema, aggressiveness, arthralgia, benign intracranial hypertension, hair loss, headache, and myalgia.
Clinical Trials in children with SGA
In clinical studies of 273 pediatric patients born small for gestational age treated with Genotropin, the following clinically significant events were reported: mild transient hyperglycemia, one patient with benign intracranial hypertension, two patients with central precocious puberty, two patients with jaw prominence, and several patients with aggravation of preexisting scoliosis, injection site reactions, and self-limited progression of pigmented nevi. Anti-hGH antibodies were not detected in any of the patients treated with Genotropin.
Clinical Trials in children with Turner Syndrome
In two clinical studies with Genotropin in pediatric patients with Turner syndrome, the most frequently reported adverse events were respiratory illnesses (influenza, tonsillitis, otitis, sinusitis), joint pain, and urinary tract infection. The only treatment-related adverse event that occurred in more than 1 patient was joint pain.
Clinical Trials in children with Idiopathic Short Stature
In two open-label clinical studies with Genotropin in pediatric patients with ISS, the most commonly encountered adverse events include upper respiratory tract infections, influenza, tonsillitis, nasopharyngitis, gastroenteritis, headaches, increased appetite, pyrexia, fracture, altered mood, and arthralgia. In one of the two studies, during Genotropin treatment, the mean IGF-1 standard deviation (SD) scores were maintained in the normal range. IGF-1 SD scores above +2 SD were observed as follows: 1 subject (3%), 10 subjects (30%) and 16 subjects (38%) in the untreated control, 0. 23 and the 0.47 mg/kg/week groups, respectively, had at least one measurement; while 0 subjects (0%), 2 subjects (7%) and 6 subjects (14%) had two or more consecutive IGF-1 measurements above +2 SD.
Clinical Trials in adults with GHD
In clinical trials with Genotropin in 1,145 GHD adults, the majority of the adverse events consisted of mild to moderate symptoms of fluid retention, including peripheral swelling, arthralgia, pain and stiffness of the extremities, peripheral edema, myalgia, paresthesia, and hypoesthesia. These events were reported early during therapy, and tended to be transient and/or responsive to dosage reduction.
Table 1 displays the adverse events reported by 5% or more of adult GHD patients in clinical trials after various durations of treatment with Genotropin. Also presented are the corresponding incidence rates of these adverse events in placebo patients during the 6-month double-blind portion of the clinical trials.
Table 1 Adverse Events Reported by ≥ 5% of 1,145 Adult GHD Patients During Clinical Trials of Genotropin and Placebo, Grouped by Duration of Treatment
|
Double Blind Phase |
Open Label Phase
Genotropin |
|---|
| Adverse Event |
Placebo
0–6 mo.
n = 572
% Patients |
Genotropin
0–6 mo.
n = 573
% Patients |
6–12 mo.
n = 504
% Patients |
12–18 mo.
n = 63
% Patients |
18–24 mo.
n = 60
% Patients |
|---|
n = number of patients receiving treatment during the indicated period.
% = percentage of patients who reported the event during the indicated period. |
|
| Swelling, peripheral |
5.1 |
17.5 |
5.6 |
0 |
1.7 |
| Arthralgia |
4.2 |
17.3* |
6.9 |
6.3 |
3.3 |
| Upper respiratory infection |
14.5 |
15.5 |
13.1 |
15.9 |
13.3 |
| Pain, extremities |
5.9 |
14.7* |
6.7 |
1.6 |
3.3 |
| Edema, peripheral |
2.6 |
10.8* |
3.0 |
0 |
0 |
| Paresthesia |
1.9 |
9.6* |
2.2 |
3.2 |
0 |
| Headache |
7.7 |
9.9 |
6.2 |
0 |
0 |
| Stiffness of extremities |
1.6 |
7.9* |
2.4 |
1.6 |
0 |
| Fatigue |
3.8 |
5.8 |
4.6 |
6.3 |
1.7 |
| Myalgia |
1.6 |
4.9* |
2.0 |
4.8 |
6.7 |
| Back pain |
4.4 |
2.8 |
3.4 |
4.8 |
5.0 |
Post-Trial Extension Studies in Adults
In expanded post-trial extension studies, diabetes mellitus developed in 12 of 3,031 patients (0.4%) during treatment with Genotropin. All 12 patients had predisposing factors, e.g., elevated glycated hemoglobin levels and/or marked obesity, prior to receiving Genotropin. Of the 3,031 patients receiving Genotropin, 61 (2%) developed symptoms of carpal tunnel syndrome, which lessened after dosage reduction or treatment interruption (52) or surgery (9). Other adverse events that have been reported include generalized edema and hypoesthesia.
Anti-hGH Antibodies
As with all therapeutic proteins, there is potential for immunogenicity. The detection of antibody formation is highly dependent on the sensitivity and specificity of the assay. Additionally, the observed incidence of antibody (including neutralizing antibody) positivity in an assay may be influenced by several factors including assay methodology, sample handling, timing of sample collection, concomitant medications, and underlying disease. For these reasons, comparison of the incidence of antibodies to Genotropin with the incidence of antibodies to other products may be misleading. In the case of growth hormone, antibodies with binding capacities lower than 2 mg/mL have not been associated with growth attenuation. In a very small number of patients treated with somatropin, when binding capacity was greater than 2 mg/mL, interference with the growth response was observed.
In 419 pediatric patients evaluated in clinical studies with Genotropin lyophilized powder, 244 had been treated previously with Genotropin or other growth hormone preparations and 175 had received no previous growth hormone therapy. Antibodies to growth hormone (anti-hGH antibodies) were present in six previously treated patients at baseline. Three of the six became negative for anti-hGH antibodies during 6 to 12 months of treatment with Genotropin. Of the remaining 413 patients, eight (1.9%) developed detectable anti-hGH antibodies during treatment with Genotropin; none had an antibody binding capacity > 2 mg/L. There was no evidence that the growth response to Genotropin was affected in these antibody-positive patients.
Periplasmic Escherichia coli Peptides
Preparations of Genotropin contain a small amount of periplasmic Escherichia coli peptides (PECP). Anti-PECP antibodies are found in a small number of patients treated with Genotropin, but these appear to be of no clinical significance.
Post-Marketing Experience
Because these adverse events are reported voluntarily from a population of uncertain size, it is not always possible to reliably estimate their frequency or establish a causal relationship to drug exposure. The adverse events reported during post-marketing surveillance do not differ from those listed/discussed above in Sections 6.1 and 6.2 in children and adults.
Leukemia has been reported in a small number of GHD children treated with somatropin, somatrem (methionylated rhGH) and GH of pituitary origin. It is uncertain whether these cases of leukemia are related to GH therapy, the pathology of GHD itself, or other associated treatments such as radiation therapy. On the basis of current evidence, experts have not been able to conclude that GH therapy per se was responsible for these cases of leukemia. The risk for children with GHD, if any, remains to be established [see Contraindications (4.3) and Warnings and Precautions (5.3)].
The following additional adverse reactions have been observed during the appropriate use of somatropin: headaches (children and adults), gynecomastia (children), and pancreatitis (children and adults, see Warnings and Precautions [5.14]).
New-onset type 2 diabetes mellitus has been reported.
Drug Interactions
11 β-Hydroxysteroid Dehydrogenase Type 1
The microsomal enzyme 11β-hydroxysteroid dehydrogenase type 1 (11βHSD-1) is required for conversion of cortisone to its active metabolite, cortisol, in hepatic and adipose tissue. GH and somatropin inhibit 11βHSD-1. Consequently, individuals with untreated GH deficiency have relative increases in 11βHSD-1 and serum cortisol. Introduction of somatropin treatment may result in inhibition of 11βHSD-1 and reduced serum cortisol concentrations. As a consequence, previously undiagnosed central (secondary) hypoadrenalism may be unmasked and glucocorticoid replacement may be required in patients treated with somatropin. In addition, patients treated with glucocorticoid replacement for previously diagnosed hypoadrenalism may require an increase in their maintenance or stress doses following initiation of somatropin treatment; this may be especially true for patients treated with cortisone acetate and prednisone since conversion of these drugs to their biologically active metabolites is dependent on the activity of 11βHSD-1.
Pharmacologic Glucocorticoid Therapy and Supraphysiologic Glucocortioid Treatment
Pharmacologic glucocorticoid therapy and supraphysiologic glucocorticoid treatment may attenuate the growth promoting effects of somatropin in children. Therefore, glucocorticoid replacement dosing should be carefully adjusted in children receiving concomitant somatropin and glucocorticoid treatments to avoid both hypoadrenalism and an inhibitory effect on growth.
Cytochrome P450-Metabolized Drugs
Limited published data indicate that somatropin treatment increases cytochrome P450 (CYP450)-mediated antipyrine clearance in man. These data suggest that somatropin administration may alter the clearance of compounds known to be metabolized by CYP450 liver enzymes (e.g., corticosteroids, sex steroids, anticonvulsants, cyclosporine). Careful monitoring is advisable when somatropin is administered in combination with other drugs known to be metabolized by CYP450 liver enzymes. However, formal drug interaction studies have not been conducted.
Oral Estrogen
In patients on oral estrogen replacement, a larger dose of somatropin may be required to achieve the defined treatment goal [see Dosage and Administration (2.2)].
Insulin and/or Oral/Injectable Hypoglycemic Agents
In patients with diabetes mellitus requiring drug therapy, the dose of insulin and/or oral/injectable agent may require adjustment when somatropin therapy is initiated [see Warnings and Precautions (5.4)]).
USE IN SPECIFIC POPULATIONS
Pregnancy
Pregnancy Category B. Reproduction studies carried out with Genotropin at doses of 0.3, 1, and 3.3 mg/kg/day administered SC in the rat and 0.08, 0.3, and 1.3 mg/kg/day administered intramuscularly in the rabbit (highest doses approximately 24 times and 19 times the recommended human therapeutic levels, respectively, based on body surface area) resulted in decreased maternal body weight gains but were not teratogenic. In rats receiving SC doses during gametogenesis and up to 7 days of pregnancy, 3.3 mg/kg/day (approximately 24 times human dose) produced anestrus or extended estrus cycles in females and fewer and less motile sperm in males. When given to pregnant female rats (days 1 to 7 of gestation) at 3.3 mg/kg/day a very slight increase in fetal deaths was observed. At 1 mg/kg/day (approximately seven times human dose) rats showed slightly extended estrus cycles, whereas at 0.3 mg/kg/day no effects were noted.
In perinatal and postnatal studies in rats, Genotropin doses of 0.3, 1, and 3.3 mg/kg/day produced growth-promoting effects in the dams but not in the fetuses. Young rats at the highest dose showed increased weight gain during suckling but the effect was not apparent by 10 weeks of age. No adverse effects were observed on gestation, morphogenesis, parturition, lactation, postnatal development, or reproductive capacity of the offsprings due to Genotropin. There are, however, no adequate and well-controlled studies in pregnant women. Because animal reproduction studies are not always predictive of human response, this drug should be used during pregnancy only if clearly needed.
Nursing Mothers
There have been no studies conducted with Genotropin in nursing mothers. It is not known whether this drug is excreted in human milk. Because many drugs are excreted in human milk, caution should be exercised when Genotropin is administered to a nursing woman.
Geriatric Use
The safety and effectiveness of Genotropin in patients aged 65 and over have not been evaluated in clinical studies. Elderly patients may be more sensitive to the action of Genotropin, and therefore may be more prone to develop adverse reactions. A lower starting dose and smaller dose increments should be considered for older patients [see Dosage and Administration (2.2)].
Overdosage
Short-Term
Short-term overdosage could lead initially to hypoglycemia and subsequently to hyperglycemia. Furthermore, overdose with somatropin is likely to cause fluid retention.
Long-Term
Long-term overdosage could result in signs and symptoms of gigantism and/or acromegaly consistent with the known effects of excess growth hormone [see Dosage and Administration (2)].
Genotropin Description
Genotropin lyophilized powder contains somatropin [rDNA origin], which is a polypeptide hormone of recombinant DNA origin. It has 191 amino acid residues and a molecular weight of 22,124 daltons. The amino acid sequence of the product is identical to that of human growth hormone of pituitary origin (somatropin). Genotropin is synthesized in a strain of Escherichia coli that has been modified by the addition of the gene for human growth hormone. Genotropin is a sterile white lyophilized powder intended for subcutaneous injection.
Genotropin 5 mg is dispensed in a two-chamber cartridge. The front chamber contains recombinant somatropin 5.8 mg, glycine 2.2 mg, mannitol 1.8 mg, sodium dihydrogen phosphate anhydrous 0.32 mg, and disodium phosphate anhydrous 0.31 mg; the rear chamber contains 0.3% m-Cresol (as a preservative) and mannitol 45 mg in 1.14 mL water for injection. The Genotropin 5 mg two-chambered cartridge contains 5.8 mg of somatropin. The reconstituted concentration is 5mg/ml . The cartridge contains overfill to allow for delivery of 1ml containing the stated amount of Genotropin – 5 mg.
Genotropin 12 mg is dispensed in a two-chamber cartridge. The front chamber contains recombinant somatropin 13.8 mg, glycine 2.3 mg, mannitol 14.0 mg, sodium dihydrogen phosphate anhydrous 0.47 mg, and disodium phosphate anhydrous 0.46 mg; the rear chamber contains 0.3% m-Cresol (as a preservative) and mannitol 32 mg in 1.13 mL water for injection. The Genotropin 12 mg two-chambered cartridge contains 13.8 mg of somatropin. The reconstituted concentration is 12 mg/ml . The cartridge contains overfill to allow for delivery of 1ml containing the stated amount of Genotropin – 12 mg.
Genotropin MINIQUICK® is dispensed as a single-use syringe device containing a two-chamber cartridge. Genotropin MINIQUICK is available as individual doses of 0.2 mg to 2.0 mg in 0.2 mg increments. The front chamber contains recombinant somatropin 0.22 to 2.2 mg, glycine 0.23 mg, mannitol 1.14 mg, sodium dihydrogen phosphate 0.05 mg, and disodium phosphate anhydrous 0.027 mg; the rear chamber contains mannitol 12.6 mg in water for injection 0.275 mL. The reconstituted Genotropin MINIQUICK two-chamber cartridge contains overfill to allow for delivery of 0.25 ml containing the stated amount of Genotropin.
Genotropin is a highly purified preparation. The reconstituted recombinant somatropin solution has an osmolality of approximately 300 mOsm/kg, and a pH of approximately 6.7. The concentration of the reconstituted solution varies by strength and presentation (see HOW SUPPLIED).
Genotropin - Clinical Pharmacology
Mechanism of Action
In vitro, preclinical, and clinical tests have demonstrated that Genotropin lyophilized powder is therapeutically equivalent to human growth hormone of pituitary origin and achieves similar pharmacokinetic profiles in normal adults. In pediatric patients who have growth hormone deficiency (GHD), have Prader-Willi syndrome (PWS), were born small for gestational age (SGA), have Turner syndrome (TS), or have Idiopathic short stature (ISS), treatment with Genotropin stimulates linear growth. In patients with GHD or PWS, treatment with Genotropin also normalizes concentrations of IGF-I (Insulin-like Growth Factor-I/Somatomedin C). In adults with GHD, treatment with Genotropin results in reduced fat mass, increased lean body mass, metabolic alterations that include beneficial changes in lipid metabolism, and normalization of IGF-I concentrations.
In addition, the following actions have been demonstrated for Genotropin and/or somatropin.
Pharmacodynamics
Tissue Growth
- A.
- Skeletal Growth: Genotropin stimulates skeletal growth in pediatric patients with GHD, PWS, SGA, TS, or ISS. The measurable increase in body length after administration of Genotropin results from an effect on the epiphyseal plates of long bones. Concentrations of IGF-I, which may play a role in skeletal growth, are generally low in the serum of pediatric patients with GHD, PWS, or SGA, but tend to increase during treatment with Genotropin. Elevations in mean serum alkaline phosphatase concentration are also seen.
- B.
- Cell Growth: It has been shown that there are fewer skeletal muscle cells in short-statured pediatric patients who lack endogenous growth hormone as compared with the normal pediatric population. Treatment with somatropin results in an increase in both the number and size of muscle cells.
Protein Metabolism
Linear growth is facilitated in part by increased cellular protein synthesis. Nitrogen retention, as demonstrated by decreased urinary nitrogen excretion and serum urea nitrogen, follows the initiation of therapy with Genotropin.
Carbohydrate Metabolism
Pediatric patients with hypopituitarism sometimes experience fasting hypoglycemia that is improved by treatment with Genotropin. Large doses of growth hormone may impair glucose tolerance.
Lipid Metabolism
In GHD patients, administration of somatropin has resulted in lipid mobilization, reduction in body fat stores, and increased plasma fatty acids.
Mineral Metabolism
Somatropin induces retention of sodium, potassium, and phosphorus. Serum concentrations of inorganic phosphate are increased in patients with GHD after therapy with Genotropin. Serum calcium is not significantly altered by Genotropin. Growth hormone could increase calciuria.
Body Composition
Adult GHD patients treated with Genotropin at the recommended adult dose (see DOSAGE AND ADMINISTRATION) demonstrate a decrease in fat mass and an increase in lean body mass. When these alterations are coupled with the increase in total body water, the overall effect of Genotropin is to modify body composition, an effect that is maintained with continued treatment.
Pharmacokinetics
Absorption
Following a 0.03 mg/kg subcutaneous (SC) injection in the thigh of 1.3 mg/mL Genotropin to adult GHD patients, approximately 80% of the dose was systemically available as compared with that available following intravenous dosing. Results were comparable in both male and female patients. Similar bioavailability has been observed in healthy adult male subjects.
In healthy adult males, following an SC injection in the thigh of 0.03 mg/kg, the extent of absorption (AUC) of a concentration of 5.3 mg/mL Genotropin was 35% greater than that for 1.3 mg/mL Genotropin. The mean (± standard deviation) peak (Cmax) serum levels were 23.0 (± 9.4) ng/mL and 17.4 (± 9.2) ng/mL, respectively.
In a similar study involving pediatric GHD patients, 5.3 mg/mL Genotropin yielded a mean AUC that was 17% greater than that for 1.3 mg/mL Genotropin. The mean Cmax levels were 21.0 ng/mL and 16.3 ng/mL, respectively.
Adult GHD patients received two single SC doses of 0.03 mg/kg of Genotropin at a concentration of 1.3 mg/mL, with a one- to four-week washout period between injections. Mean Cmax levels were 12.4 ng/mL (first injection) and 12.2 ng/mL (second injection), achieved at approximately six hours after dosing.
There are no data on the bioequivalence between the 12 mg/mL formulation and either the 1.3 mg/mL or the 5.3 mg/mL formulations.
