Lisa Abbott, MD, endocrinologist with Northern Nevada Endocrinology, discusses the expansion of broader dosing ranges of Skytrofa (lonapegsomatropin) now available for the replacement of endogenous growth hormone in adults with growth hormone deficiency (GHD).
GHD is a rare condition characterized by insufficient amounts of growth hormone produced by the pituitary gland. GHD can be acquired but is often congenital, with possible mutations in the POU1F1/Pit1, PROP1, GHRH and GH1 genes. It can also be caused by tumors in the pituitary and hypothalamus, surgical or radiation damage, traumatic brain injury, and pituitary damage due to childbirth. Signs and symptoms may include short stature, slow growth or absence of growth, absent or delayed sexual development during puberty, and headaches.
Skytrofa (Lonapegsomatropin)
Lonapegsomatropin is a prodrug of somatropin administered once weekly that provides sustained release of active, unmodified somatropin. It was initially approved by the U.S. Food and Drug Administration (FDA) in August 2021 for pediatric GHD and was recently indicated for adults in July 2025. To learn how this TransCon technology works, visit ascendispharma.com/technology/#howitworks
foresiGHt Clinical Trial
The recent approval in adults follows results from the phase 3, randomized, parallel-arm, placebo-controlled, double-blind, active-controlled, open-label foresiGHt clinical trial evaluating the safety and efficacy of weekly lonapegsomatropin with weekly placebo and daily somatropin in adults with GHD.
The trial enrolled 259 adults with GHD who were treated with lonapegsomatropin, placebo, or somatropin. Lonapegsomatropin demonstrated superiority in the primary endpoint of change from baseline in trunk percent fat at week 28 versus placebo. It also showed superirority in key secondary endpoints of change from baseline in total body lean mass and change from baselin in trunk fat mass. Mean total exposure and maintenance doses were similar in lonapegsomatropin and somatropin arms, with larger change from baseline in average IGF-I SDS mean at week 38 in the lonapegsomatropin group compared to placebo.
Lonapegosomatropin was generally well-tolerated, with a low incidence of serious adverse events. Incidence of treatment-related adverse events was similar across arms.
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To learn more about GHD and other rare endocrine conditions, visit https://checkrare.com/diseases/endocrine-disorders/