Skytrofa 5.2mg Inj Cartridge
It is used to help with growth and to treat growth hormone deficiency.
Drug Class
Growth hormone
Pharmacologic Class
Recombinant human growth hormone (rhGH) analog; PEGylated somatropin prodrug
Pregnancy Category
Not available
FDA Approved
Aug 2021
DEA Schedule
Not Controlled
Overview
What is this medicine?
Skytrofa is a long-acting medicine that contains a form of human growth hormone. It is given as a shot under the skin once a week to help children who are not growing properly because their bodies don't make enough growth hormone.
How to Use This Medicine
Proper Administration of This Medication
To ensure your child receives this medication safely and effectively, follow the instructions provided by their doctor. Carefully read all accompanying information and follow the instructions precisely.
This medication is administered via injection into the fatty tissue of the skin, typically on the right or left side of the stomach, thigh, or buttocks. If you will be giving your child the injection, their doctor or nurse will provide guidance on the proper technique.
Before administering the medication, make sure you understand the instructions for use. If you have any questions or concerns, consult with the doctor or pharmacist. The instructions for use will also be provided with the medication.
Preparation and Administration
If the medication has been stored in the refrigerator, allow it to reach room temperature before use. Remove it from the refrigerator and let it sit at room temperature for 15 minutes. Do not heat the medication.
This medication requires mixing before administration. Follow the mixing instructions provided by the doctor.
When administering the injection, rotate the injection site with each dose to minimize the risk of skin irritation. Avoid injecting through clothing, and do not administer the medication into skin that is irritated, bruised, red, infected, hard, or scarred.
Wash your hands before and after handling the medication. Do not use the medication if the solution appears cloudy, is leaking, or contains particles. Additionally, do not use the medication if the solution has changed color.
After mixing the medication, do not refrigerate it. Use the medication within 4 hours of preparation. Dispose of needles and other sharp objects in a designated needle/sharp disposal box. Do not reuse needles or other items. When the disposal box is full, follow local regulations for proper disposal. If you have any questions, consult with a doctor or pharmacist.
Storage and Disposal
Store the medication in the refrigerator to maintain its potency. Do not freeze the medication. Keep the medication in its original carton to protect it from light. If necessary, you can store the medication at room temperature for up to 6 months. Record the date you remove the medication from the refrigerator. You can return the medication to the refrigerator within the 6-month period. Discard the medication if it is not used within 6 months of removal from the refrigerator.
Missed Dose
If you miss a dose, administer it as soon as possible. However, if your child misses a dose by more than 2 days, skip the missed dose and resume the regular schedule. Do not administer two doses within 5 days of each other.
To ensure your child receives this medication safely and effectively, follow the instructions provided by their doctor. Carefully read all accompanying information and follow the instructions precisely.
This medication is administered via injection into the fatty tissue of the skin, typically on the right or left side of the stomach, thigh, or buttocks. If you will be giving your child the injection, their doctor or nurse will provide guidance on the proper technique.
Before administering the medication, make sure you understand the instructions for use. If you have any questions or concerns, consult with the doctor or pharmacist. The instructions for use will also be provided with the medication.
Preparation and Administration
If the medication has been stored in the refrigerator, allow it to reach room temperature before use. Remove it from the refrigerator and let it sit at room temperature for 15 minutes. Do not heat the medication.
This medication requires mixing before administration. Follow the mixing instructions provided by the doctor.
When administering the injection, rotate the injection site with each dose to minimize the risk of skin irritation. Avoid injecting through clothing, and do not administer the medication into skin that is irritated, bruised, red, infected, hard, or scarred.
Wash your hands before and after handling the medication. Do not use the medication if the solution appears cloudy, is leaking, or contains particles. Additionally, do not use the medication if the solution has changed color.
After mixing the medication, do not refrigerate it. Use the medication within 4 hours of preparation. Dispose of needles and other sharp objects in a designated needle/sharp disposal box. Do not reuse needles or other items. When the disposal box is full, follow local regulations for proper disposal. If you have any questions, consult with a doctor or pharmacist.
Storage and Disposal
Store the medication in the refrigerator to maintain its potency. Do not freeze the medication. Keep the medication in its original carton to protect it from light. If necessary, you can store the medication at room temperature for up to 6 months. Record the date you remove the medication from the refrigerator. You can return the medication to the refrigerator within the 6-month period. Discard the medication if it is not used within 6 months of removal from the refrigerator.
Missed Dose
If you miss a dose, administer it as soon as possible. However, if your child misses a dose by more than 2 days, skip the missed dose and resume the regular schedule. Do not administer two doses within 5 days of each other.
Lifestyle & Tips
- Administer the injection exactly as prescribed by your doctor, once weekly on the same day each week.
- Rotate injection sites (thighs, buttocks, abdomen, upper arms) to prevent skin problems.
- Store the medicine properly as instructed (refrigerated, do not freeze).
- Do not shake the cartridge.
- Follow up with your doctor regularly for blood tests and growth monitoring.
- Maintain a balanced diet and regular exercise as recommended by your healthcare provider.
Available Forms & Alternatives
Dosing & Administration
Adult Dosing
Standard Dose:
Not indicated for adult growth hormone deficiency (GHD) in the US.
Pediatric Dosing
Neonatal:
Not established
Infant:
Not established
Child:
Initial dose: 0.24 mg/kg/week administered once weekly by subcutaneous injection. Dose may be adjusted based on IGF-1 levels and clinical response, up to a maximum of 0.48 mg/kg/week.
Adolescent:
Initial dose: 0.24 mg/kg/week administered once weekly by subcutaneous injection. Dose may be adjusted based on IGF-1 levels and clinical response, up to a maximum of 0.48 mg/kg/week.
Dose Adjustments
Renal Impairment:
Mild:
No specific dose adjustment recommended.
Moderate:
No specific dose adjustment recommended.
Severe:
No specific dose adjustment recommended. Use with caution due to limited data.
Dialysis:
Not available. Use with caution due to limited data.
Hepatic Impairment:
Mild:
No specific dose adjustment recommended.
Moderate:
No specific dose adjustment recommended.
Severe:
No specific dose adjustment recommended. Use with caution due to limited data.
Pharmacology
Mechanism of Action
Lonapegsomatropin is a prodrug of somatropin (recombinant human growth hormone). It is a long-acting, PEGylated form of somatropin. After subcutaneous injection, lonapegsomatropin undergoes proteolytic cleavage to release unmodified somatropin. Somatropin binds to growth hormone receptors on target cells, stimulating linear growth in pediatric patients with GHD by promoting cellular protein synthesis, increasing utilization of body fat, and mobilizing carbohydrates.
Pharmacokinetics
Absorption:
Bioavailability:
Not directly reported for lonapegsomatropin, but somatropin is released systemically.
Tmax:
Median Tmax for released somatropin is approximately 84 hours (range: 24 to 168 hours) after a single subcutaneous dose of lonapegsomatropin.
FoodEffect:
Not applicable (parenteral administration).
Distribution:
Vd:
Volume of distribution for released somatropin is approximately 0.12 L/kg.
ProteinBinding:
Not extensively protein bound.
CnssPenetration:
Limited
Elimination:
HalfLife:
Terminal half-life of released somatropin is approximately 25-30 hours after lonapegsomatropin administration.
Clearance:
Systemic clearance of released somatropin is approximately 0.005 L/hr/kg.
ExcretionRoute:
Renal and hepatic.
Unchanged:
Not available
Pharmacodynamics
OnsetOfAction:
Growth effects are gradual and sustained over time.
PeakEffect:
Peak IGF-1 levels are typically observed within 3-5 days after a weekly dose.
DurationOfAction:
Approximately 7 days (due to the long-acting nature of the prodrug).
Safety & Warnings
Side Effects
Urgent Side Effects: Seek Medical Attention Immediately
Although rare, some people may experience severe and potentially life-threatening side effects while taking this medication. If your child exhibits any of the following symptoms, contact their doctor or seek medical help right away:
Signs of an allergic reaction, such as:
+ Rash
+ Hives
+ Itching
+ Red, swollen, blistered, or peeling skin with or without fever
+ Wheezing
+ Tightness in the chest or throat
+ Trouble breathing, swallowing, or talking
+ Unusual hoarseness
+ Swelling of the mouth, face, lips, tongue, or throat
Signs of high blood sugar, including:
+ Confusion
+ Feeling sleepy
+ Unusual thirst or hunger
+ Passing urine more often
+ Flushing
+ Fast breathing
+ Breath that smells like fruit
Signs of pancreatitis (pancreas problem), such as:
+ Severe stomach pain
+ Severe back pain
+ Severe upset stomach or vomiting
Signs of a weak adrenal gland, including:
+ Severe upset stomach or vomiting
+ Severe dizziness or passing out
+ Muscle weakness
+ Feeling very tired
+ Mood changes
+ Decreased appetite
+ Weight loss
Signs of low thyroid levels, such as:
+ Constipation
+ Sensitivity to cold
+ Memory problems
+ Mood changes
+ Burning, numbness, or tingling sensations
Signs of infection, including:
+ Fever
+ Chills
+ Severe sore throat
+ Ear or sinus pain
+ Cough
+ Increased or discolored sputum
+ Pain while urinating
+ Mouth sores
+ Wounds that won't heal
A skin lump or growth
Changes in the color or size of a mole
Skin breakdown at the site of application
Unexplained bruising or bleeding
Muscle or joint pain
Burning, numbness, pain, or tingling in the hands, arms, wrists, legs, or feet
Children using this medication may rarely experience a bone problem in the hip (slipped growth plate); seek medical attention if your child has hip or knee pain or a limp
Severe bone problems have been reported; contact the doctor if your child experiences new or worsening bone pain
Raised pressure in the head has rarely occurred, particularly in patients with Turner syndrome or Prader-Willi syndrome; seek medical attention if your child experiences:
+ Changes in vision
+ Severe headache
+ Upset stomach
+ Vomiting
Other Possible Side Effects
Most medications can cause side effects, but many people experience none or only mild symptoms. If your child experiences any of the following side effects or any other symptoms that concern you, contact their doctor or seek medical help:
Upset stomach or vomiting
* Stomach pain or diarrhea
This is not an exhaustive list of potential side effects. If you have questions or concerns about side effects, consult your child's doctor.
Although rare, some people may experience severe and potentially life-threatening side effects while taking this medication. If your child exhibits any of the following symptoms, contact their doctor or seek medical help right away:
Signs of an allergic reaction, such as:
+ Rash
+ Hives
+ Itching
+ Red, swollen, blistered, or peeling skin with or without fever
+ Wheezing
+ Tightness in the chest or throat
+ Trouble breathing, swallowing, or talking
+ Unusual hoarseness
+ Swelling of the mouth, face, lips, tongue, or throat
Signs of high blood sugar, including:
+ Confusion
+ Feeling sleepy
+ Unusual thirst or hunger
+ Passing urine more often
+ Flushing
+ Fast breathing
+ Breath that smells like fruit
Signs of pancreatitis (pancreas problem), such as:
+ Severe stomach pain
+ Severe back pain
+ Severe upset stomach or vomiting
Signs of a weak adrenal gland, including:
+ Severe upset stomach or vomiting
+ Severe dizziness or passing out
+ Muscle weakness
+ Feeling very tired
+ Mood changes
+ Decreased appetite
+ Weight loss
Signs of low thyroid levels, such as:
+ Constipation
+ Sensitivity to cold
+ Memory problems
+ Mood changes
+ Burning, numbness, or tingling sensations
Signs of infection, including:
+ Fever
+ Chills
+ Severe sore throat
+ Ear or sinus pain
+ Cough
+ Increased or discolored sputum
+ Pain while urinating
+ Mouth sores
+ Wounds that won't heal
A skin lump or growth
Changes in the color or size of a mole
Skin breakdown at the site of application
Unexplained bruising or bleeding
Muscle or joint pain
Burning, numbness, pain, or tingling in the hands, arms, wrists, legs, or feet
Children using this medication may rarely experience a bone problem in the hip (slipped growth plate); seek medical attention if your child has hip or knee pain or a limp
Severe bone problems have been reported; contact the doctor if your child experiences new or worsening bone pain
Raised pressure in the head has rarely occurred, particularly in patients with Turner syndrome or Prader-Willi syndrome; seek medical attention if your child experiences:
+ Changes in vision
+ Severe headache
+ Upset stomach
+ Vomiting
Other Possible Side Effects
Most medications can cause side effects, but many people experience none or only mild symptoms. If your child experiences any of the following side effects or any other symptoms that concern you, contact their doctor or seek medical help:
Upset stomach or vomiting
* Stomach pain or diarrhea
This is not an exhaustive list of potential side effects. If you have questions or concerns about side effects, consult your child's doctor.
Seek Immediate Medical Attention If You Experience:
- Severe or persistent headache, especially with nausea, vomiting, or vision changes (e.g., blurred vision, double vision)
- New or worsening limping, or hip/knee pain
- Signs of high blood sugar (increased thirst, increased urination, unexplained weight loss, fatigue)
- Signs of an underactive thyroid (fatigue, weight gain, constipation, feeling cold)
- New or worsening curvature of the spine (scoliosis)
- Any signs of an allergic reaction (rash, itching, swelling, severe dizziness, trouble breathing)
Before Using This Medicine
Before Your Child Takes This Medication: Important Information to Share with Your Doctor
It is essential to inform your child's doctor about the following:
Any allergies your child may have to this medication, its components, or other substances, including foods and drugs. Please describe the allergic reaction and its symptoms.
If your child has any of the following health conditions:
+ Breathing problems, such as sleep apnea
+ Cancer or other tumors, including brain tumors
+ Diabetic eye disease
+ Recent illness after open heart surgery, stomach surgery, or accidental injury
If your child has Prader-Willi syndrome and is severely overweight, experiences breathing difficulties, or has sleep apnea
If your child's bones have stopped growing (closed epiphyses)
This list is not exhaustive, and it is crucial to discuss all your child's medications (prescription, over-the-counter, natural products, and vitamins) and health problems with the doctor and pharmacist. To ensure safe treatment, verify that it is safe to administer this medication with all your child's other medications and health conditions. Never start, stop, or adjust the dosage of any medication your child is taking without consulting the doctor.
It is essential to inform your child's doctor about the following:
Any allergies your child may have to this medication, its components, or other substances, including foods and drugs. Please describe the allergic reaction and its symptoms.
If your child has any of the following health conditions:
+ Breathing problems, such as sleep apnea
+ Cancer or other tumors, including brain tumors
+ Diabetic eye disease
+ Recent illness after open heart surgery, stomach surgery, or accidental injury
If your child has Prader-Willi syndrome and is severely overweight, experiences breathing difficulties, or has sleep apnea
If your child's bones have stopped growing (closed epiphyses)
This list is not exhaustive, and it is crucial to discuss all your child's medications (prescription, over-the-counter, natural products, and vitamins) and health problems with the doctor and pharmacist. To ensure safe treatment, verify that it is safe to administer this medication with all your child's other medications and health conditions. Never start, stop, or adjust the dosage of any medication your child is taking without consulting the doctor.
Precautions & Cautions
It is essential to inform all of your child's healthcare providers, including doctors, nurses, pharmacists, and dentists, that your child is taking this medication.
Your child may be at risk for high blood sugar, including the development of new or worsening diabetes, while taking this drug. To monitor this, follow the doctor's instructions for checking your child's blood sugar levels. Additionally, adhere to the recommended schedule for your child's blood work and eye exams as advised by their doctor.
This medication may interfere with certain laboratory tests. Therefore, it is crucial to notify all of your child's healthcare providers and laboratory personnel that your child is taking this drug.
If your child experiences any changes in weight, consult with their doctor, as this may necessitate an adjustment in the dosage of this medication.
Do not share this product or any associated needles or syringes with another person, even if the needle has been changed. Sharing can lead to the transmission of infections, including those that may not be immediately apparent, from one person to another.
One potential side effect of this medication is excessive fluid retention in the body, which can, in some cases, lead to heart failure. If your child exhibits symptoms such as shortness of breath, significant weight gain, or swelling in the arms or legs, contact their doctor immediately.
If your child has scoliosis, an abnormal curvature of the spine, discuss this with their doctor, as this medication may exacerbate the condition in children who are still growing.
For children with a history of cancer or tumors, it is essential to consult with their doctor, as this medication may increase the risk of cancer or tumor growth. Additionally, the development of new tumors may be more likely in some patients.
Children with Prader-Willi syndrome are at a higher risk for severe and potentially fatal respiratory problems while taking this medication. This risk may be increased in children who have sleep apnea, lung or airway infections, airway obstruction, or are significantly overweight. If your child has a fever of 100.4°F (38°C) or higher, cough, sore throat, shortness of breath, chest pain or discomfort, new or worsening snoring, or abnormal breathing during sleep, contact their doctor immediately.
If your child is pregnant or breastfeeding, it is crucial to discuss the benefits and risks of this medication with their doctor, as this will help determine the best course of action for both your child and the baby.
Your child may be at risk for high blood sugar, including the development of new or worsening diabetes, while taking this drug. To monitor this, follow the doctor's instructions for checking your child's blood sugar levels. Additionally, adhere to the recommended schedule for your child's blood work and eye exams as advised by their doctor.
This medication may interfere with certain laboratory tests. Therefore, it is crucial to notify all of your child's healthcare providers and laboratory personnel that your child is taking this drug.
If your child experiences any changes in weight, consult with their doctor, as this may necessitate an adjustment in the dosage of this medication.
Do not share this product or any associated needles or syringes with another person, even if the needle has been changed. Sharing can lead to the transmission of infections, including those that may not be immediately apparent, from one person to another.
One potential side effect of this medication is excessive fluid retention in the body, which can, in some cases, lead to heart failure. If your child exhibits symptoms such as shortness of breath, significant weight gain, or swelling in the arms or legs, contact their doctor immediately.
If your child has scoliosis, an abnormal curvature of the spine, discuss this with their doctor, as this medication may exacerbate the condition in children who are still growing.
For children with a history of cancer or tumors, it is essential to consult with their doctor, as this medication may increase the risk of cancer or tumor growth. Additionally, the development of new tumors may be more likely in some patients.
Children with Prader-Willi syndrome are at a higher risk for severe and potentially fatal respiratory problems while taking this medication. This risk may be increased in children who have sleep apnea, lung or airway infections, airway obstruction, or are significantly overweight. If your child has a fever of 100.4°F (38°C) or higher, cough, sore throat, shortness of breath, chest pain or discomfort, new or worsening snoring, or abnormal breathing during sleep, contact their doctor immediately.
If your child is pregnant or breastfeeding, it is crucial to discuss the benefits and risks of this medication with their doctor, as this will help determine the best course of action for both your child and the baby.
Overdose Information
Overdose Symptoms:
- Acute overdose: Hypoglycemia (low blood sugar) initially, followed by hyperglycemia (high blood sugar).
- Chronic overdose: Signs and symptoms of gigantism and/or acromegaly (e.g., excessive growth, enlarged hands/feet, joint pain, carpal tunnel syndrome).
What to Do:
Seek immediate medical attention. Acute overdose may require glucose administration. Chronic overdose requires discontinuation of the drug and symptomatic management. Call 1-800-222-1222 (Poison Control Center).
Drug Interactions
Major Interactions
- Glucocorticoids (may inhibit growth-promoting effects of lonapegsomatropin)
- Insulin and/or other antidiabetic agents (may require dose adjustment of antidiabetic agents)
Moderate Interactions
- Thyroid hormone replacement (may require dose adjustment of thyroid hormone)
- Oral estrogen (may require higher doses of somatropin)
Monitoring
Baseline Monitoring
IGF-1 and IGFBP-3 levels
Rationale: To confirm GHD diagnosis and establish baseline for treatment monitoring.
Timing: Prior to initiation of therapy
Thyroid function tests (TSH, Free T4)
Rationale: To rule out hypothyroidism, which can impair growth response.
Timing: Prior to initiation of therapy
Fasting glucose and HbA1c
Rationale: To assess glucose metabolism and screen for diabetes.
Timing: Prior to initiation of therapy
Bone age
Rationale: To assess skeletal maturity and growth potential.
Timing: Prior to initiation of therapy
Height and weight
Rationale: To establish baseline growth parameters.
Timing: Prior to initiation of therapy
Fundoscopic examination
Rationale: To screen for papilledema, especially in patients with risk factors for intracranial hypertension.
Timing: Prior to initiation of therapy
Routine Monitoring
IGF-1 levels
Frequency: Approximately 4 weeks after initiation or dose change, then every 3-6 months
Target: Age- and sex-adjusted normal range (0 to +2 SDS)
Action Threshold: If IGF-1 levels are consistently above +2 SDS, consider dose reduction. If consistently below -2 SDS, consider dose increase.
Growth velocity (height and weight)
Frequency: Every 3-6 months
Target: Increased growth velocity appropriate for age
Action Threshold: Lack of expected growth response may indicate need for dose adjustment or re-evaluation of diagnosis/compliance.
Fasting glucose and HbA1c
Frequency: Annually, or more frequently if risk factors for diabetes develop
Target: Normal ranges
Action Threshold: Elevated levels may require dose adjustment or initiation of antidiabetic therapy.
Thyroid function tests
Frequency: Annually, or if clinical signs of hypothyroidism develop
Target: Normal ranges
Action Threshold: Abnormalities may require thyroid hormone replacement or adjustment.
Fundoscopic examination
Frequency: Periodically, or if symptoms of intracranial hypertension occur
Target: No papilledema
Action Threshold: Presence of papilledema requires immediate evaluation and potential discontinuation of therapy.
Scoliosis screening
Frequency: Periodically during rapid growth
Target: Not applicable
Action Threshold: Development or progression of scoliosis requires orthopedic evaluation.
Symptom Monitoring
- Persistent severe headache
- Visual changes (e.g., blurred vision, double vision)
- Nausea or vomiting
- Limping or hip/knee pain (slipped capital femoral epiphysis)
- New or worsening scoliosis
- Signs of hyperglycemia (increased thirst, urination, fatigue)
- Signs of hypothyroidism (fatigue, weight gain, constipation, cold intolerance)
- Injection site reactions (pain, redness, swelling)
Special Patient Groups
Pregnancy
Risk Summary: Available data with somatropin use in pregnant women are insufficient to determine a drug-associated risk of adverse developmental outcomes. Animal reproduction studies have not been conducted with lonapegsomatropin. Use only if clearly needed and potential benefits outweigh risks.
Trimester-Specific Risks:
First Trimester:
Not available
Second Trimester:
Not available
Third Trimester:
Not available
Lactation
Risk Summary: There is no information regarding the presence of lonapegsomatropin in human milk, the effects on the breastfed infant, or the effects on milk production. The developmental and health benefits of breastfeeding should be considered along with the mother’s clinical need for Skytrofa and any potential adverse effects on the breastfed infant from Skytrofa or from the underlying maternal condition. Caution should be exercised when Skytrofa is administered to a nursing mother.
Infant Risk:
Not available
Pediatric Use
Skytrofa is indicated for the treatment of pediatric patients 1 year and older with growth hormone deficiency (GHD). Safety and effectiveness have been established in pediatric patients. Dosing is weight-based and adjusted according to IGF-1 levels and growth response.
Geriatric Use
The safety and effectiveness of Skytrofa in patients 65 years of age and older have not been established. Skytrofa is not indicated for adult GHD. Use with caution in elderly patients due to potential for increased sensitivity to adverse effects and comorbidities.
Clinical Information
Clinical Pearls
- Skytrofa is a once-weekly injection, which can improve adherence compared to daily growth hormone injections.
- It is a prodrug that releases unmodified somatropin, providing sustained exposure.
- Careful monitoring of IGF-1 levels is crucial for dose titration to ensure efficacy and minimize adverse effects.
- Patients and caregivers must be thoroughly trained on proper subcutaneous injection technique and cartridge handling.
- Patients should be monitored for signs of intracranial hypertension, glucose intolerance, and slipped capital femoral epiphysis.
Alternative Therapies
- Daily somatropin injections (e.g., Genotropin, Humatrope, Norditropin, Nutropin, Saizen, Zomacton)
- Other long-acting somatropin formulations (e.g., Ngenla (somatrogon-ghla), Sogroya (somapacitan-beco))
Cost & Coverage
Average Cost:
Highly variable, typically >$10,000 - $20,000+ per month (depending on dose and cartridge size)
Insurance Coverage:
Specialty Tier (requires prior authorization, often subject to step therapy and quantity limits)
General Drug Facts
If your child's symptoms or health issues persist or worsen, it is essential to contact their doctor promptly. To ensure safe and effective treatment, never share your child's medication with others, and do not administer someone else's medication to your child. Some medications may include an additional patient information leaflet; if you have questions or concerns about this medication, consult with your child's doctor, nurse, pharmacist, or other healthcare provider. In the event of a suspected overdose, immediately call the poison control center or seek emergency medical attention. When reporting the incident, be prepared to provide detailed information, including the substance taken, the amount, and the time it occurred.