FDA Approved Growth Hormone Axis

Somatrogon

also known as: Ngenla, MOD-4023, OPK-88003, CTP-modified hGH, somatrogon-ghla

Pfizer/OPKO's once-weekly growth hormone (Ngenla) — FDA-approved in June 2023 for pediatric GH deficiency in children aged 3+ years; uses a CTP-fusion strategy borrowed from long-acting follitropin alfa.

A once-weekly recombinant growth hormone fusion protein in which three copies of the hCG β-subunit C-terminal peptide (CTP) — a naturally O-glycosylated 28-amino-acid sequence — are fused to the N- and C-termini of somatropin to extend plasma half-life. FDA-approved as Ngenla in June 2023 for pediatric GH deficiency in patients aged 3 years and older, following earlier EMA (2022), Canadian, Japanese, and Australian approvals. The CTP-fusion approach is the same half-life-extension technology used in long-acting follitropin alfa (choriogonadotropin alfa / corifollitropin).

Mechanism of action

Binds the GH receptor with affinity comparable to native somatropin, activating JAK2/STAT5 signaling and IGF-1 production. The CTP (C-terminal peptide) domains — O-glycosylated with four negatively charged sialic acid residues per copy — shield the fusion protein from renal filtration and proteolytic clearance, extending circulating half-life. This is the same CTP-fusion technology used in long-acting follitropin alfa (Elonva) for reproductive medicine.

Primary uses

  • Pediatric growth hormone deficiency (age 3+)

Typical dosing

0.66 mg/kg/week once weekly (subcutaneous)

Fixed weekly dosing of 0.66 mg/kg via a prefilled auto-injector pen. Patient-reported outcomes studies favored weekly somatrogon over daily somatropin on burden-of-treatment scales.

Regulatory status

FDA-approved June 2023 as Ngenla (Pfizer, developed in partnership with OPKO Health) for pediatric growth hormone deficiency aged 3 years and older. Previously approved EMA (February 2022), Health Canada (October 2021), Japan, Australia, and additional markets.

References

  1. [fda-pi] Ngenla (somatrogon-ghla) Prescribing Information. Pfizer.
  2. [clinical-trial] Deal CL, et al. "Efficacy and Safety of Weekly Somatrogon vs Daily Somatropin in Children with GH Deficiency: A Phase 3 Study." J Clin Endocrinol Metab, 2022;107:e2717-e2728.
  3. [manufacturer] Pfizer. "FDA approves Ngenla (somatrogon-ghla) for pediatric growth hormone deficiency." Press release, June 28, 2023.

Related peptides

Somatropin (HGH)

FDA-approved recombinant human growth hormone — the direct hormone replacement, with multiple clinical indications, prescription-only status, and specific federal criminal provisions against off-label distribution.

Somapacitan

Novo Nordisk's once-weekly growth hormone (Sogroya) — FDA-approved in 2020 for adult GH deficiency and in 2023 for pediatric GH deficiency in children aged 2.5+ years.

Lonapegsomatropin

Ascendis Pharma's once-weekly growth hormone prodrug (Skytrofa) — the first weekly GH to receive FDA approval (August 2021) for pediatric GH deficiency in patients aged 1+ years weighing at least 11.5 kg.

Sermorelin

The N-terminal 29 amino acids of native GHRH — a former FDA-approved diagnostic and pediatric GH-deficiency therapy, now widely compounded for adult anti-aging protocols.
Disclaimer

This entry is for educational purposes only and does not constitute medical advice. Dosing information reflects published regulatory or research data and is not a recommendation. Many compounds described here are not approved for human use in the United States. Consult a licensed medical professional before considering any peptide therapy.