Skytrofa

Pediatric Growth Hormone Deficiency

Skytrofa is indicated for the treatment of growth failure in children 1 year of age and older who weigh at least 11.5 kilograms (approximately 25.4 pounds). It is used specifically for pediatric patients whose bodies do not produce enough endogenous growth hormone, a condition known as growth hormone deficiency (GHD).

Adult Growth Hormone Deficiency

This medication is also approved for use in adults with growth hormone deficiency. This includes:

• Adults who were diagnosed with growth hormone deficiency as children and require ongoing treatment into adulthood.
• Adults who developed growth hormone deficiency later in life due to medical conditions, surgery, radiation, or injury affecting the pituitary gland or hypothalamus.

In both children and adults, the medication acts as a replacement for the growth hormone the body is unable to produce on its own, which is necessary for normal growth, body composition, and metabolism.

Mechanism of Action

Skytrofa is a prodrug of somatropin, which is a human growth hormone. It is designed using technology that attaches the hormone to a carrier molecule, allowing it to be released gradually after injection. This slow-release mechanism enables the medication to maintain steady levels of growth hormone in the body over the course of a week.

How it Stimulates Growth

Once the active somatropin is released into the bloodstream, it binds to growth hormone receptors on various tissues. This interaction stimulates the production of insulin-like growth factor-1 (IGF-1), a hormone primarily made in the liver that is essential for growth. Together, these hormones promote several biological effects:

• Bone Growth: They stimulate the growth plates in long bones, which helps children with growth hormone deficiency increase their height.
• Tissue Development: They encourage the growth of skeletal muscles and internal organs.
• Metabolism: They play a role in how the body processes proteins, fats, and carbohydrates.

By replacing the growth hormone that the body is not producing enough of on its own, Skytrofa helps support normal physical development and metabolic function.

Common Side Effects

The most common side effects reported with Skytrofa include:

• Viral infections
• Fever
• Cough
• Nausea and vomiting
• Diarrhea or stomach pain
• Headache
• Joint pain or pain in the limbs
• Injection site reactions, such as redness, itching, or swelling

Serious Side Effects

Contact a healthcare provider immediately if you or your child experience any of the following serious side effects:

• Increased brain pressure: Symptoms include severe headache, vision changes, nausea, and vomiting.
• Severe allergic reactions: Signs include rash, hives, swelling of the face or throat, and difficulty breathing.
• Hip or knee issues: A new limp or pain in the hip or knee may indicate a bone problem called slipped capital femoral epiphysis.
• Worsening scoliosis: Growth hormone can cause an existing curvature of the spine to worsen.
• High blood sugar: Symptoms include increased thirst, frequent urination, and fatigue.
• Pancreatitis: Severe pain in the upper stomach area that radiates to the back.
• Adrenal insufficiency: Symptoms include extreme tiredness, dizziness, or muscle weakness.

Contraindications

Skytrofa should not be used in patients with the following conditions:

• Acute critical illness resulting from certain types of surgery, multiple accidental trauma, or acute respiratory failure.
• Active malignancy (cancer).
• Hypersensitivity to lonapegsomatropin or any of its components.
• Active proliferative or severe non-proliferative diabetic retinopathy.
• Closed epiphyses (when growth plates have finished growing).

Serious Warnings and Precautions

Increased Mortality: Growth hormone therapy has been linked to an increased risk of death in patients with certain acute critical illnesses. If a patient becomes critically ill, treatment is typically discontinued.

Risk of Malignancy: There is a potential for preexisting tumors to progress or recur. Patients with a history of cancer require close monitoring, and treatment should be stopped if there is evidence of active malignancy. New skin lesions or changes in existing moles should be monitored.

Glucose Intolerance and Diabetes: Treatment may decrease insulin sensitivity, which can lead to high blood sugar or the development of type 2 diabetes. Regular monitoring of blood glucose levels is necessary, particularly for patients with preexisting diabetes or risk factors.

Intracranial Hypertension: Increased pressure in the brain has been reported. Symptoms may include severe headache, visual changes, nausea, and vomiting. Healthcare providers usually perform funduscopic examinations before and during treatment to monitor for this condition.

Hormonal Adjustments: Skytrofa can affect how the body processes other hormones. It may unmask central hypoadrenalism or hypothyroidism, or it may require adjustments to existing glucocorticoid or thyroid replacement therapies.

Bone and Joint Issues: Rapid growth may cause the progression of preexisting scoliosis. Additionally, pediatric patients may develop slipped capital femoral epiphysis (a hip condition). Any patient who develops a limp or hip and knee pain should be evaluated by a professional.

Pancreatitis: Inflammation of the pancreas should be considered in patients who experience persistent, severe abdominal pain while taking this medication.

Injection Site Reactions: To prevent localized skin changes such as lipoatrophy (loss of fat tissue), injection sites must be rotated regularly.

Pregnancy

There are no adequate or well-controlled studies regarding the use of Skytrofa in pregnant women. It is currently unknown whether the medication can cause harm to an unborn baby or affect a person's ability to become pregnant. Additionally, animal reproduction studies have not been conducted with this specific drug.

If you are pregnant or planning to become pregnant, you should discuss the potential risks and benefits of this treatment with your healthcare provider. Skytrofa should be used during pregnancy only if the potential benefit clearly outweighs the potential risk to the fetus.

Breastfeeding

It is not known if Skytrofa passes into human breast milk, how it might affect a nursing infant, or if it has any impact on milk production. While the active growth hormone in the medication is known to be present in human milk, it is generally considered unlikely to be absorbed by the infant's digestive system.

If you are breastfeeding or planning to breastfeed, consult your doctor to determine the safest course of action for you and your child. Decisions regarding treatment while breastfeeding should consider the importance of the drug to the mother and the potential effects on the infant.

Dosage Forms

Skytrofa is supplied as a sterile, preservative-free powder contained within a dual-chamber prefilled cartridge. This cartridge is designed for use with a specific auto-injector device.

The medication is prepared by mixing the powder with the included diluent within the cartridge before administration. Each cartridge is intended for a single dose only and is administered via subcutaneous injection.

FDA Approval and Indications

The U.S. Food and Drug Administration (FDA) approved Skytrofa in August 2021. It is indicated for the treatment of pediatric patients 1 year of age and older who weigh at least 11.5 kg (approximately 25.4 pounds) and have growth failure due to inadequate secretion of endogenous growth hormone.

Regulatory Status

Skytrofa is a prodrug of somatropin designed for once-weekly subcutaneous injection. It is not currently subject to a boxed warning or a Risk Evaluation and Mitigation Strategy (REMS) program.

Safety Monitoring

The FDA monitors the safety of approved medications through the FDA Adverse Event Reporting System (FAERS). In early 2024, the FDA identified a potential signal of serious risk regarding adrenal insufficiency and hypoadrenalism associated with lonapegsomatropin-tcgd. The agency is currently evaluating the need for regulatory action, such as potential updates to the product labeling.

Factors Affecting Cost

The price of Skytrofa can vary based on several factors. Because it is a specialty medication, it is typically obtained through specialty pharmacies rather than standard retail pharmacies. The total cost may be influenced by:

• Insurance Coverage: Your out-of-pocket expenses will depend on your specific health insurance plan, including your deductible, copay, or coinsurance requirements.
• Prior Authorization: Most insurance providers require prior authorization before they will cover Skytrofa. This process involves your healthcare provider submitting documentation to prove the medical necessity of the drug.
• Dosage: The prescribed dose and the number of cartridges needed per month will affect the overall cost.

Generic Availability

Skytrofa is a brand-name medication. There is currently no generic version available. Brand-name drugs are generally more expensive than generic alternatives.

Financial Assistance

Financial support may be available to help manage the cost of Skytrofa. These programs are often provided by the manufacturer and may include:

• Copay Cards: Patients with commercial insurance may be eligible for copay savings cards that reduce the amount paid at the pharmacy.
• Patient Assistance Programs: These programs may provide the medication at a reduced cost or for free to individuals who meet specific income requirements or who do not have insurance coverage.