Skytrofa 9.1mg Inj Cartridge

Manufacturer ASCENDIS PHARMA Active Ingredient Lonapegsomatropin Injection(LOE na peg SOE ma TROE pin) Pronunciation LOE na peg SOE ma TROE pin
It is used to help with growth and to treat growth hormone deficiency.
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Drug Class
Growth Hormone
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Pharmacologic Class
Recombinant Human Growth Hormone Analog
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Pregnancy Category
Not available
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FDA Approved
Aug 2021
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DEA Schedule
Not Controlled

Overview

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What is this medicine?

Skytrofa is a medicine given by injection once a week to help children with growth hormone deficiency grow taller. It works like the natural growth hormone your body makes.
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How to Use This Medicine

Administering This Medication

To ensure your child receives this medication correctly, 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 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 how to use it. Refer to the instructions for use that come with the medication. If you have any questions or concerns, consult with the doctor or pharmacist.

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.

Preparing the Medication

This medication requires mixing before use. Follow the instructions provided by the doctor on how to mix the medication.

Injection Technique

When administering the injection, rotate the injection site with each dose. Avoid injecting through clothing and do not inject into skin that is irritated, bruised, red, infected, hard, or scarred. Wash your hands before and after use.

Inspecting the Medication

Before use, inspect the solution for cloudiness, leakage, or particles. Do not use the medication if the solution has changed color or appears abnormal.

Using the Medication

After mixing, do not refrigerate the medication. Use the medication within 4 hours of preparation. Dispose of needles and other sharp objects in a designated 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, but do not freeze. 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 Doses

If a dose is missed, administer it as soon as possible. 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.
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Lifestyle & Tips

  • Administer the injection subcutaneously (under the skin) once a week, on the same day each week, at any time of day.
  • Rotate injection sites (thighs, abdomen, buttocks, upper arms) to prevent lipoatrophy.
  • Store the cartridge in the refrigerator (2Β°C to 8Β°C / 36Β°F to 46Β°F). Do not freeze. Protect from light.
  • Once the cartridge is inserted into the Skytrofa Auto-Injector, it can be stored at room temperature (up to 25Β°C / 77Β°F) for up to 7 days, or in the refrigerator for up to 28 days. Discard after 28 days or if left out of the refrigerator for more than 7 days.
  • Follow a balanced diet and engage in regular physical activity as recommended by your doctor.
  • Attend all scheduled doctor appointments and laboratory tests to monitor treatment effectiveness and safety.

Dosing & Administration

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Adult Dosing

Standard Dose: Not indicated for adult growth hormone deficiency.
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Pediatric Dosing

Neonatal: Not established
Infant: Not established
Child: Initial dose: 0.24 mg/kg/week administered subcutaneously once weekly. Dose should be individualized based on patient's weight, growth response, and IGF-1 levels. Max dose: 0.48 mg/kg/week.
Adolescent: Initial dose: 0.24 mg/kg/week administered subcutaneously once weekly. Dose should be individualized based on patient's weight, growth response, and IGF-1 levels. Max dose: 0.48 mg/kg/week. Discontinue when epiphyses are closed.
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Dose Adjustments

Renal Impairment:

Mild: No dose adjustment needed.
Moderate: No dose adjustment needed.
Severe: No dose adjustment needed.
Dialysis: No specific recommendations; use with caution and monitor IGF-1 levels closely.

Hepatic Impairment:

Mild: No dose adjustment needed.
Moderate: No dose adjustment needed.
Severe: No dose adjustment needed.

Pharmacology

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Mechanism of Action

Lonapegsomatropin is a C-terminally PEGylated human growth hormone (somatropin) prodrug. It is a long-acting analog of somatropin. After subcutaneous injection, lonapegsomatropin is slowly cleaved to release somatropin. Somatropin binds to growth hormone (GH) receptors on target cells, stimulating linear growth and protein, carbohydrate, and lipid metabolism. It mediates its effects partly by stimulating the production of insulin-like growth factor-1 (IGF-1).
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Pharmacokinetics

Absorption:

Bioavailability: Not available (prodrug conversion)
Tmax: Approximately 75 hours (for somatropin released from lonapegsomatropin)
FoodEffect: Not applicable (subcutaneous injection)

Distribution:

Vd: Not available (for lonapegsomatropin); for released somatropin, similar to endogenous GH
ProteinBinding: Not available (for lonapegsomatropin); for released somatropin, low binding to plasma proteins
CnssPenetration: Limited

Elimination:

HalfLife: Approximately 25-30 hours (for somatropin released from lonapegsomatropin)
Clearance: Not available
ExcretionRoute: Renal and hepatic
Unchanged: Not available
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Pharmacodynamics

OnsetOfAction: Gradual (due to prodrug nature and extended release)
PeakEffect: IGF-1 levels peak approximately 4-5 days after weekly dosing.
DurationOfAction: Sustained effect over 7 days, allowing weekly dosing.

Safety & Warnings

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Side Effects

Urgent Side Effects: Seek Medical Help Right Away

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 attention immediately:

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 changed sputum production
+ 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 occurred with this medication; 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 exhibits:
+ 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 attention:

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. Always contact their doctor for medical advice regarding side effects.
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Seek Immediate Medical Attention If You Experience:

  • Severe or new headaches, especially if accompanied by nausea, vomiting, or vision changes (e.g., blurred vision, double vision). These could be signs of increased pressure in the brain.
  • New or worsening limping, or hip/knee pain, which could indicate a slipped capital femoral epiphysis.
  • Changes in existing moles or skin lesions, or development of new ones.
  • Increased thirst, increased urination, or unexplained weight loss, which could be signs of high blood sugar.
  • Signs of an allergic reaction, such as rash, itching, hives, swelling of the face, lips, tongue, or throat, or difficulty breathing.
  • Persistent pain, redness, or swelling at the injection site.
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Before Using This Medicine

Before Your Child Takes This Medication: Important Information to Share with Your Doctor

It is essential to inform your doctor about the following:

If your child is allergic to this medication, any of its components, or any other substances, including foods or 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 without consulting your doctor.
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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-onset diabetes or worsening of existing diabetes. Monitor your child's blood sugar levels as directed by their doctor. Regular blood work and eye exams are also crucial, as scheduled by their doctor.

This medication may interfere with certain laboratory tests. Be sure to notify all healthcare providers and laboratory personnel that your child is taking this medication.

If your child experiences any changes in weight, consult with their doctor, as the dosage of this medication may need to be adjusted.

Do not share this medication, needles, or syringes with anyone, even if the needle has been changed. Sharing can lead to the transmission of infections, including those that may not be immediately apparent.

Be aware that this medication can cause fluid retention, which may lead to heart failure in some cases. 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, consult with their doctor, as this medication may exacerbate the condition in growing children.

Children with a history of cancer or tumors should discuss the potential risks with their doctor, as this medication may increase the likelihood of cancer or tumor growth. Additionally, the development of new tumors may be a concern for some patients.

Children with Prader-Willi syndrome are at a higher risk for severe and potentially life-threatening respiratory problems. This risk may be increased in children with sleep apnea, lung or airway infections, airway obstruction, or obesity. If your child experiences a fever of 100.4Β°F (38Β°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, consult with their doctor to discuss the potential benefits and risks to both your child and the baby.
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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, facial changes).

What to Do:

Seek immediate medical attention. Acute overdose may require glucose administration for hypoglycemia. Chronic overdose requires discontinuation of the drug and symptomatic management. Call 1-800-222-1222 (Poison Control).

Drug Interactions

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Major Interactions

  • Glucocorticoids (may inhibit growth-promoting effects)
  • Thyroid hormones (may affect growth response; monitor thyroid function)
  • Insulin and/or other antidiabetic agents (may require dose adjustment due to potential for glucose intolerance)
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Moderate Interactions

  • Cytochrome P450-metabolized drugs (e.g., corticosteroids, sex steroids, anticonvulsants, cyclosporine) - GH may increase CYP450 activity, potentially altering drug clearance.

Monitoring

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Baseline Monitoring

IGF-1 levels

Rationale: To establish baseline and guide initial dosing.

Timing: Prior to initiation of therapy.

Thyroid function tests (TSH, Free T4)

Rationale: Hypothyroidism can interfere with growth response to GH. GH therapy can unmask central hypothyroidism.

Timing: Prior to initiation of therapy.

Fasting glucose and HbA1c

Rationale: To assess baseline glucose metabolism, as GH can induce insulin resistance.

Timing: Prior to initiation of therapy.

Fundoscopic examination

Rationale: To rule out pre-existing papilledema, especially in patients with risk factors for intracranial hypertension.

Timing: Prior to initiation of therapy.

Bone age (X-ray of left wrist and hand)

Rationale: To assess skeletal maturity and predict remaining growth potential.

Timing: Prior to initiation of therapy.

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Routine Monitoring

IGF-1 levels

Frequency: Every 3-6 months, or as clinically indicated after dose adjustments.

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)

Frequency: Every 3-6 months.

Target: Increased growth velocity appropriate for age and pubertal status.

Action Threshold: Lack of adequate growth response may indicate need for dose adjustment or investigation of other causes.

Thyroid function tests (TSH, Free T4)

Frequency: Every 6-12 months, or if clinical signs of hypothyroidism develop.

Target: Normal range.

Action Threshold: Treat hypothyroidism if present, as it can impair growth response.

Fasting glucose and HbA1c

Frequency: Annually, or if clinical signs of glucose intolerance develop.

Target: Normal range.

Action Threshold: If elevated, consider dose adjustment or initiation of antidiabetic therapy.

Fundoscopic examination

Frequency: Periodically, or if symptoms of intracranial hypertension (e.g., severe headache, visual changes) occur.

Target: No papilledema.

Action Threshold: If papilledema is present, discontinue therapy and refer to neurology/ophthalmology.

Scoliosis screening

Frequency: Annually, especially during periods of rapid growth.

Target: No significant spinal curvature.

Action Threshold: If scoliosis develops or worsens, monitor closely.

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Symptom Monitoring

  • Headache (especially severe or persistent)
  • Visual changes (e.g., blurred vision, double vision)
  • Nausea/vomiting (unexplained)
  • Limping or hip/knee pain (slipped capital femoral epiphysis)
  • Changes in skin lesions (e.g., moles, nevi)
  • Injection site reactions (pain, redness, swelling)
  • Signs of allergic reaction (rash, itching, swelling, difficulty breathing)
  • Symptoms of glucose intolerance (increased thirst, urination, fatigue)
  • Symptoms of hypothyroidism (fatigue, weight gain, constipation, cold intolerance)

Special Patient Groups

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Pregnancy

There are no adequate and well-controlled studies of lonapegsomatropin in pregnant women. Use during pregnancy only if the potential benefit justifies the potential risk to the fetus. Animal studies have shown no evidence of teratogenicity.

Trimester-Specific Risks:

First Trimester: Risk cannot be ruled out. Use only if clearly needed.
Second Trimester: Risk cannot be ruled out. Use only if clearly needed.
Third Trimester: Risk cannot be ruled out. Use only if clearly needed.
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Lactation

It is not known whether lonapegsomatropin is excreted in human milk. Because many drugs are excreted in human milk, caution should be exercised when Skytrofa is administered to a nursing mother. Consider the developmental and health benefits of breastfeeding 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.

Infant Risk: Risk unknown. Potential for adverse effects on breastfed infant.
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Pediatric Use

Skytrofa is indicated for the treatment of pediatric patients 1 year and older with growth hormone deficiency. Safety and effectiveness in infants younger than 1 year have not been established. Dosing is weight-based and adjusted according to IGF-1 levels and growth response. Treatment should be discontinued once epiphyses are closed.

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Geriatric Use

Safety and effectiveness in geriatric patients have not been established. Skytrofa is not indicated for adult growth hormone deficiency. Growth hormone deficiency in adults is typically treated with daily somatropin preparations.

Clinical Information

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Clinical Pearls

  • Skytrofa is a long-acting growth hormone prodrug, allowing for once-weekly subcutaneous administration, which may improve adherence compared to daily injections.
  • The dose is individualized based on weight, growth response, and IGF-1 levels. Regular monitoring of IGF-1 is crucial to prevent over- or under-dosing.
  • Patients and caregivers should be thoroughly trained on proper injection technique and site rotation.
  • Monitor for signs and symptoms of increased intracranial pressure (e.g., severe headache, visual changes) and slipped capital femoral epiphysis (e.g., limping, hip/knee pain).
  • Hypothyroidism can impair the growth response to growth hormone therapy; ensure thyroid function is normal or adequately treated.
  • Growth hormone therapy can induce insulin resistance; monitor glucose levels, especially in patients with risk factors for diabetes.
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Alternative Therapies

  • Somatropin (e.g., Genotropin, Humatrope, Norditropin, Nutropin, Omnitrope, Saizen, Zomacton) - daily subcutaneous injections.
  • Somapacitan-beco (Sogroya) - once-weekly subcutaneous injection (approved for adults, not pediatric GHD).
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Cost & Coverage

Average Cost: Highly variable, typically several thousand dollars per month
Insurance Coverage: Specialty Tier (requires prior authorization, often subject to step therapy)
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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 come with an additional patient information leaflet; if you have any 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 medical attention. When reporting the incident, be prepared to provide details about the medication taken, the quantity, and the time it occurred.