General Information

Ngenla (somatrogon-ghla) is a human growth hormone analog that works by replacing the lack of growth hormone in the body. 

Ngenla is specifically indicated for the treatment of pediatric patients aged 3 years and older who have growth failure due to an inadequate secretion of endogenous growth hormone.

Dosing/Administration

• Ngenla is supplied as an injection for subcutaneous administration. 
• The recommended dosage of Ngenla is 0.66 mg/kg based on actual body weight administered once weekly by subcutaneous (SC) injection.
• Individualize dosage for each patient based on the growth response.
• The day of weekly administration can be changed if necessary as long as the time between 2 doses is at least 3 days. After selecting a new dosing day, the once weekly dosing should be continued.
•  When switching from daily growth hormone, the once-weekly Ngenla may be initiated on the day following their last daily injection.
• If more than one injection is required to deliver a complete dose, each injection should be administered at a different injection site.
•  If a dose is missed, administer Ngenla as soon as possible within 3 days after the missed dose.
• If more than 3 days have passed, skip the missed dose and administer the next dose on the regularly scheduled day. 

Mechanism of Action

Somatrogon-ghla binds to the growth hormone (GH) receptor and initiates a signal transduction cascade culminating in changes in growth and metabolism. Somatrogon-ghla binding leads to activation of the STAT5b signaling pathway and increases the serum concentration of Insulin-like Growth Factor (IGF-1). GH and IGF-1 stimulate metabolic changes, linear growth, and enhance growth velocity in pediatric patients with GHD.

Side Effects

Adverse effects associated with the use of Ngenla may include, but are not limited to, the following:

• injection site reactions
• nasopharyngitis
• headache
• pyrexia
• anemia
• cough

Clinical Trial Results

The FDA approval of Ngenla was based on results from a multi-center, randomized, open-label, active-controlled phase 3 study in 224 treatment-naïve, prepubertal pediatric subjects with growth hormone deficiency (GHD). The primary efficacy endpoint was annualized height velocity at Week 52. Subjects received 0.66 mg/kg/week Ngenla or 0.034 mg/kg/day daily somatropin. The subjects age ranged from 3 to 12 years, with a mean of 7.7 years. The study met its primary endpoint of Ngenla non-inferiority compared to somatropi. Treatment with once-weekly Ngenla for 52 weeks resulted in an annualized height velocity of 10.1 cm/year. Patients treated with daily somatropin achieved an annualized height velocity of 9.8 cm/year after 52 weeks of treatment.