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Informational, not medical advice

This is an approved / prescription medicine. Do not use without a prescription and medical supervision.

EMA-approvedaka Skytrofa, TransCon hGH

Lonapegsomatropin — Complete Research Guide (2026)

Last updated 2026-06-30

TL;DR

Lonapegsomatropin (also known as Skytrofa) is a peptide catalogued under Growth Hormone (Long-acting PEGylated GH). It is described as: GH receptor. Documented context: Pediatric GHD. Neutral reference entry; EU status: EU-approved prescription medicine.

What is Lonapegsomatropin?

Lonapegsomatropin (lonapegsomatropin-tcgd, brand name Skytrofa) is a long-acting prodrug of somatropin built on TransCon PEG technology, in which unmodified growth hormone is transiently linked to a PEG carrier and released slowly, enabling once-weekly subcutaneous dosing.

It is an approved prescription medicine for pediatric growth hormone deficiency (FDA 2021; EMA 2022), for eligible patients meeting weight thresholds.

Evidence is human and high quality, anchored by the pivotal phase 3 heiGHt trial versus daily somatropin plus the enliGHten and fliGHt extension/switch studies.

How does Lonapegsomatropin work?

Once injected, the prodrug gradually releases fully active, unmodified somatropin, which activates the growth hormone receptor to raise IGF-1 and drive linear bone growth.

The sustained PEG-carrier release maintains growth hormone exposure across the week, replacing daily somatropin injections with a single weekly dose.

What does the research say about Lonapegsomatropin?

  • In the phase 3 heiGHt trial, once-weekly lonapegsomatropin produced greater 52-week annualized height velocity than daily somatropin in treatment-naive children with GHD. [1]
  • Height velocity and safety were sustained through the enliGHten open-label extension over multiple years. [2]
  • Children switched from daily somatropin to weekly lonapegsomatropin (fliGHt) maintained growth with comparable tolerability. [3]

Clinical research & studies

The references below are the primary sources cited throughout this guide. Each links directly to PubMed or the regulator. Where evidence is preclinical (animal or in-vitro), that is stated rather than implied.

  • [1] Weekly Lonapegsomatropin in Treatment-Naive Children With Growth Hormone Deficiency: The Phase 3 heiGHt Trial — Thornton PS et al., Journal of Clinical Endocrinology and Metabolism 2021. (Phase 3 randomized controlled trial)
  • [2] Safety and Efficacy of Lonapegsomatropin in Children With Growth Hormone Deficiency: enliGHten Trial 2-Year Results — Maniatis AK et al., Journal of Clinical Endocrinology and Metabolism 2022. (Phase 3 open-label extension)
  • [3] Switching to Weekly Lonapegsomatropin from Daily Somatropin in Children with Growth Hormone Deficiency: The fliGHt Trial — Maniatis AK et al., Hormone Research in Paediatrics 2022. (Phase 3 switch trial)
  • [4] Children with Growth Hormone Deficiency Treated with Lonapegsomatropin Demonstrated Sustained Height Improvements for up to 6 Years: enliGHten Trial Final Results — Maniatis AK et al., Hormone Research in Paediatrics 2026. (Phase 3 extension (final results))
  • [5] Spotlight on Lonapegsomatropin Once-Weekly Injection and Its Potential in the Treatment of Growth Hormone Deficiency in Pediatric Patients — Miller BS et al., Drug Design, Development and Therapy 2022. (Narrative review)

Dosing context

This is not medical advice or a usage recommendation. Dosing figures are reported research context only, cited from the published literature.

For context only: lonapegsomatropin is given as a once-weekly subcutaneous injection via a dedicated auto-injector, with weight-based dosing set and titrated by an endocrinologist using IGF-1 and growth response.

This is background information rather than dosing guidance; prescribing, titration, and monitoring must be performed by a qualified clinician.

Side effects & safety profile

Class growth-hormone safety applies: injection-site reactions are common, and clinicians monitor for glucose intolerance/new-onset diabetes, intracranial hypertension, slipped capital femoral epiphysis, and scoliosis progression during growth.

It is contraindicated in acute critical illness and active malignancy and must be used under endocrinologist supervision with IGF-1 monitoring; a minimum body-weight threshold applies to the device and dosing.

Lonapegsomatropin is an approved pediatric GHD therapy, not an anti-aging or performance-enhancing peptide; using growth hormone for those purposes is unsupported and potentially harmful.

Stacking & combinations

No approved or evidence-based regimen combines lonapegsomatropin with other GH products, anabolic agents, or unapproved peptides, and such combinations can compound metabolic and endocrine risk.

Finding Lonapegsomatropin vendors

Finding Lonapegsomatropin vendors

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Frequently asked questions

It is approved for pediatric growth hormone deficiency as a once-weekly injection for eligible patients; it is a prescription endocrine medicine.

References

  1. [1] Weekly Lonapegsomatropin in Treatment-Naive Children With Growth Hormone Deficiency: The Phase 3 heiGHt Trial — Thornton PS et al., Journal of Clinical Endocrinology and Metabolism 2021. PMID: 34272849. View sourceStudy: Phase 3 randomized controlled trialWeekly lonapegsomatropin achieved higher 52-week annualized height velocity than daily somatropin with comparable safety.
  2. [2] Safety and Efficacy of Lonapegsomatropin in Children With Growth Hormone Deficiency: enliGHten Trial 2-Year Results — Maniatis AK et al., Journal of Clinical Endocrinology and Metabolism 2022. PMID: 35428884. View sourceStudy: Phase 3 open-label extensionSustained height velocity and no new safety signals were seen over two years of weekly lonapegsomatropin.
  3. [3] Switching to Weekly Lonapegsomatropin from Daily Somatropin in Children with Growth Hormone Deficiency: The fliGHt Trial — Maniatis AK et al., Hormone Research in Paediatrics 2022. PMID: 35263755. View sourceStudy: Phase 3 switch trialChildren switching from daily GH to weekly lonapegsomatropin maintained growth with a consistent safety profile.
  4. [4] Children with Growth Hormone Deficiency Treated with Lonapegsomatropin Demonstrated Sustained Height Improvements for up to 6 Years: enliGHten Trial Final Results — Maniatis AK et al., Hormone Research in Paediatrics 2026. PMID: 40049149. View sourceStudy: Phase 3 extension (final results)Height improvements were sustained for up to six years without new safety concerns.
  5. [5] Spotlight on Lonapegsomatropin Once-Weekly Injection and Its Potential in the Treatment of Growth Hormone Deficiency in Pediatric Patients — Miller BS et al., Drug Design, Development and Therapy 2022. PMID: 35791404. View sourceStudy: Narrative reviewReview summarizes the TransCon mechanism and phase 3 evidence supporting weekly lonapegsomatropin in pediatric GHD.
This article is for educational and research purposes only. Peptides discussed here are not approved for human consumption by the FDA, EMA, or equivalent regulators outside of specific clinical contexts. Always consult a licensed medical professional before any therapeutic use.