FDA OKs Skytrofa for Growth Hormone Deficiency in Adults

The FDA has approved the once-weekly injectable lonapegsomatropin-tcgd (Skytrofa, Ascendis Pharma A/S) for replacing endogenous growth hormone in adults with growth hormone deficiency (GHD), expanding on the current indication for pediatric GHD.

GHD, a rare disorder resulting from insufficient levels of growth hormone, is linked to short height in children and metabolic complications in adults. Current treatment consists of daily somatropin injections however adherence can be a challenge for many patients.

Lonapegsomatropin — a prodrug of somatropin, or human growth hormone — provides sustained release of active, unmodified somatropin through once-weekly injections.

The drug was first approved in 2021 for pediatric patients with GHD who are 1 year or older and weigh at least 26 pounds.

The approval for adults was based on results from the phase 3, double-blind, randomized foresiGHt trial, in which lonapegsomatropin was compared 1:1:1 with daily somatropin and weekly placebo injections in 259 adults with GHD.

Lonapegsomatropin was found to be significantly superiority at 38 weeks in the primary outcome of change from baseline (CFB) in trunk percent of fat and the key secondary efficacy endpoint of CFB in total lean body mass (both P <.0001), as well as other measures.

In terms of safety, severe adverse events (AEs) were low (lonapegsomatropin, 3.4%; placebo, 1.2%; somatropin, 2.3%), and the incidence of treatment-related AEs between lonapegsomatropin and somatropin were similar (24.7% and 22.1%, respectively). 

The most common side effects in adults included swelling due to fluid build-up and low thyroid hormone.

‘No Surprise’ Patients Desire a More Convenient Treatment Regimen

The hallmarks of GHD — including abnormal body composition, dyslipidemia, and insulin resistance — place patients at risk of serious medical complications including metabolic syndrome and increased cardiovascular risk, explained Kevin Yuen, MD, of the Barrow Neurological Institute, University of Arizona College of Medicine and Creighton University School of Medicine in Phoenix, in an FDA press statement.

The condition can further impair quality-of-life factors including cognitive dysfunction, depression, anxiety, sleep disturbance, and reduced physical and mental drive, he said. 

Therefore, “it is no surprise that patients are looking for a less burdensome treatment regimen, and a new treatment option,” Yuen said.