Lonapegsomatropin-tcgd injection

Skytrofa (lonapegsomatropin-tcgd) is a once-weekly injectable human growth hormone with two approved uses:

• Skytrofa for children: Treats growth failure in pediatric patients 1 year and older who weigh at least 11.5 kg (about 25 lbs) and whose bodies do not produce enough growth hormone on their own (growth hormone deficiency).
• Skytrofa for adults: Replaces growth hormone in adults diagnosed with growth hormone deficiency (GHD).

Skytrofa is a pegylated (chemically modified) form of human growth hormone called somatropin. The pegylation keeps it active in the body long enough for once-weekly dosing. After injection, Skytrofa slowly releases active somatropin, which binds to growth hormone receptors on cells throughout the body. This triggers the production of IGF-1 (insulin-like growth factor-1), a key messenger that stimulates bone growth at the growth plates in children, supports protein building, promotes fat breakdown, and regulates glucose (sugar) output from the liver.

Skytrofa is given as a subcutaneous (under-the-skin) injection once a week using the Skytrofa Auto-Injector device. It is injected into the abdomen, buttock, or thigh, and the site should be rotated with each injection. There are no food restrictions around dosing.

• If a dose is missed, give it as soon as possible — but only within 2 days of the missed day. If more than 2 days have passed, skip the missed dose and resume the regular schedule.
• At least 5 days should pass between any two doses.
• Your prescriber will set the right dose for you or your child based on body weight, age, and response to treatment — always follow their specific instructions.

The most common side effects reported with Skytrofa in clinical trials include:

• In children: viral infections, fever, cough, nausea and vomiting, minor bleeding (such as nosebleeds or bruising), diarrhea, abdominal pain, and joint pain or inflammation
• In adults: peripheral edema (swelling, especially in the limbs) and worsening or newly detected hypothyroidism (low thyroid)

Serious reactions that need prompt medical attention include severe allergic reactions (anaphylaxis or angioedema), signs of high pressure inside the skull (bad headache, vision changes), significant blood sugar changes, and a new limp or hip/knee pain in children — contact your doctor or seek emergency care if these occur.

• Acute critical illness: Skytrofa must NOT be used during serious acute illness (after major surgery, major injury, or acute respiratory failure) — use of pharmacologic growth hormone doses in these situations has been linked to increased mortality.
• Cancer risk: Skytrofa is contraindicated in patients with active malignancy. In childhood cancer survivors who received brain radiation, there is an increased risk of a second tumor (especially meningiomas). All patients should be monitored for signs of new or returning tumors.
• Blood sugar: Skytrofa can reduce insulin sensitivity and may reveal hidden type 2 diabetes — blood sugar monitoring is important, especially in those with risk factors.
• Intracranial hypertension (high pressure in the skull): Can cause headache, vision changes, nausea, and vomiting. An eye exam is needed before starting treatment, and symptoms usually resolve with dose reduction or stopping the drug.
• Slipped capital femoral epiphysis (a shift in the hip growth plate): Can occur in growing children — report any new limp or hip/knee pain promptly.
• Prader-Willi syndrome in children: Skytrofa is NOT for children with growth failure due to genetically confirmed Prader-Willi syndrome — there have been reports of sudden death in obese children or those with breathing problems in this group.
• Thyroid and cortisol levels: Skytrofa can unmask or worsen hypothyroidism and can lower cortisol levels, particularly in people already on steroid replacement — periodic monitoring is needed.

Skytrofa can interact with several types of medications, so your doctor needs to know everything you take:

• Glucocorticoid replacements (e.g., cortisone, prednisone): Skytrofa can reduce how much active cortisol is available, possibly requiring an increase in your steroid dose.
• High-dose glucocorticoids in children: May blunt the growth-promoting effect of Skytrofa; careful dose adjustment is needed.
• Drugs metabolized by CYP450 liver enzymes: Skytrofa can change how quickly the liver processes certain medications — ask your pharmacist if any of your medications are affected.
• Oral estrogen: Can reduce the IGF-1 response to Skytrofa, meaning a higher dose of Skytrofa may be needed for women taking oral estrogen.
• Insulin and other diabetes medications: Skytrofa can lower insulin sensitivity, so diabetes drug doses may need to be adjusted when starting or changing Skytrofa.

This is not a complete list of interactions. Always talk with your doctor or pharmacist before starting, stopping, or changing any medication.

• Do not use Skytrofa if you have an active cancer — any existing malignancy must be fully treated and inactive before starting.
• Do not use Skytrofa if you are critically ill after major surgery, serious trauma, or acute respiratory failure.
• Children with Prader-Willi syndrome who are severely obese, have a history of airway obstruction or sleep apnea, or have severe breathing problems should not use Skytrofa.
• Children whose growth plates (epiphyses) have already closed should not use Skytrofa.
• Tell your doctor if you have or have had diabetic retinopathy (eye complications from diabetes) — active proliferative or severe non-proliferative diabetic retinopathy is a contraindication.
• Tell your doctor if you have diabetes, thyroid problems, adrenal insufficiency, scoliosis, or a history of any tumor — these conditions require extra monitoring.
• Pregnant patients: no controlled human studies are available; discuss the risks and benefits with your doctor before using Skytrofa during pregnancy.
• Breastfeeding: limited data exist; the drug is expected to have very low passage into breast milk, but discuss with your doctor.
• Older adults (age 60 and above): treatment is started at a lower dose because the risk of side effects may be higher.

Taking too much Skytrofa can first cause low blood sugar (hypoglycemia) and then, over time, high blood sugar (hyperglycemia). Fluid retention is also possible with overdose. Long-term excess growth hormone can cause abnormal bone and tissue growth. If you think you or your child may have received too much, contact a healthcare provider or poison control center right away.

After Skytrofa is injected, the growth hormone it releases (somatropin) stimulates IGF-1 production in a dose-dependent way — meaning more drug leads to a predictable, proportional rise in IGF-1 levels. IGF-1 levels peak around 2 days after the injection and remain in the normal range for most of the week. This steady weekly profile closely resembles what daily growth hormone injections achieve, without requiring daily dosing.

After a subcutaneous injection of Skytrofa, the drug slowly releases active somatropin through an automatic chemical process called autocleavage of the TransCon linker. The drug reaches peak blood levels roughly 25–31 hours after injection, and the released somatropin has a half-life (the time it takes for half the drug to leave the body) of about 25 hours — which is what makes once-weekly dosing possible. Somatropin is broken down (metabolized) mainly by the liver and kidneys. The carrier component of the drug is cleared by the kidneys. Age, sex, race, and body weight do not have clinically meaningful effects on how the body handles Skytrofa.

Refrigerate SKYTROFA cartridges at 36°F to 46°F (2°C to 8°C) in the outer carton to protect from light until the expiration date. Do not freeze. stored at room temperature for up to 6 months and can be returned to refrigeration within the 6 months.