FDA

Skytrofa now approved for adults with growth hormone deficiency

July 31, 2025

FDA approved Skytrofa (lonapegsomatropin-tcgd) for the replacement of endogenous growth hormone (GH) in adults with GH deficiency (GHD). Skytrofa is a pegylated human growth hormone (somatropin) for once-weekly SC injection.

The product was previously approved for the treatment of pediatric patients ≥1 year of age weighing ≥11.5 kg with growth failure due to inadequate secretion of endogenous GH.

Efficacy

Approval of Skytrofa for adult GHD was based on data from foresiGHt (NCT04615273), a phase 3 randomized, parallel-arm, placebo-controlled (double-blind) and active-controlled (open-label) clinical trial that compared the efficacy and safety of weekly lonapegsomatropin with weekly placebo and daily somatropin in 259 adults with GHD.

The primary efficacy endpoint, change in trunk percent (%) fat, was measured by dual X-ray absorptiometry from baseline to week 38 in the Skytrofa group, compared with the placebo group. Patients treated with daily somatropin achieved a change in trunk percent fat of -3.1% after 38 weeks. No formal statistical comparison between Skytrofa and daily somatropin was conducted.

Secondary efficacy endpoints: At 38 weeks, the change from baseline in total body lean mass was +1.6 kg for lonapegsomatropin and -0.1 kg for placebo (least squares [LS] mean difference of 1.7 kg with 95% confidence interval [CI] of 1.0 - 2.5; p-value < 0.0001). At 38 weeks, the change from baseline in trunk fat mass was -0.5 kg for lonapegsomatropin and +0.2 kg for placebo (LS mean difference of -0.7 kg with 95% CI of -1.2 to -0.2; p-value = 0.005).

After 38 weeks, Skytrofa treatment in adults with GHD resulted in normalization of IGF-1 SDS to 1.4 compared with -2.6 in placebo-treated patients. The mean (SD) IGF-1 standard deviation score (SDS) level in daily somatropin-treated patients was -2.82 (1) at baseline and 0.49 (1.98) at 38 weeks. No formal statistical comparison between Skytrofa and daily somatropin was conducted.

Safety

The most common adverse reaction among adults (≥5%) was peripheral edema.

Sources:

Skytrofa (lonapegsomatropin-tcgd) [package insert]. Food and Drug Administration. https://www.accessdata.fda.gov/drugsatfda_docs/label/2025/761177s008lbl.pdf Revised July 2025. Accessed July 30, 2025.

FDA approves Skytrofa® (Lonapegsomatropin-tcgd) for the once-weekly treatment of adults with growth hormone deficiency. [News release]. 2025. https://investors.ascendispharma.com/news-releases/news-release-details/fda-approves-skytrofar-lonapegsomatropin-tcgd-once-weekly