Molecule & formulation science
Inpegsomatropin is the international nonproprietary name for the active ingredient in Pegpesen®. This page connects structural intent, clinical pharmacology, and formulation choices.
Y‑shaped PEGylated architecture
The registrational program and peer-reviewed literature describe inpegsomatropin as a PEGylated recombinant human growth hormone built around a Y‑shaped PEG scaffold. That geometry is part of how Amoytop engineers hydrodynamic volume and clearance—supporting a weekly dosing interval in the approved pediatric GHD indication (China). For mechanistic and efficacy detail at publication depth, see Liang et al., J Clin Endocrinol Metab 2024.
Pharmacologic equivalence to native GH
Inpegsomatropin exerts equivalent pharmacological activity to endogenous human growth hormone: stimulation of skeletal and somatic growth, metabolic regulation, lean mass gain and fat mass reduction when GH deficiency is corrected, and predominantly IGF‑1–mediated downstream signaling with IGFBP involvement.
IGF‑1 dynamics at the characterized weekly dose
Clinical pharmacology data indicate IGF‑1 reaching steady state in about eight weeks with median Tmax 48 h at steady state for the characterized weekly regimen. Peak and trough IGF‑1 means are reported in Clinical pharmacology—the pattern reflects extended-interval dosing rather than daily peaks and troughs of conventional rhGH. A separate population PK/PD publication simulates how alternative titration and banded-dose strategies might behave over two years; see the Phase II study and PK/PD modeling topic (theoretical; not prescriptive labeling).
Excipients
The drug product contains mannitol, sodium acetate, glacial acetic acid, sodium chloride, and lysine acetate. The formulation is described as free of antimicrobial preservatives. Technical claims on this page track the published Phase III paper and the product information sections linked from the hub.
How this fits other long-acting GH platforms
Globally, long-acting GH approaches differ (PEGylation, depots, fusion proteins, prodrugs). Inpegsomatropin’s profile—weekly administration, immunogenicity results in the China Phase III trial, and paired TopPen I delivery—is discussed clinically in Clinical trials and Adverse events & immunogenicity.