Introduction: Lonapegsomatropin (SKYTROFA, TransCon hGH), a prodrug of somatropin administered once-weekly, is approved for the treatment of pediatric growth hormone deficiency (GHD) by the Food and Drug Administration and European Commission. In the pivotal 52-week phase 3 heiGHt trial and 26-week fliGHt trial (enrolled treatment-naïve and treatment-experienced participants, respectively), lonapegsomatropin demonstrated safety and efficacy in children with GHD. The final results of long-term safety and efficacy in the open-label extension trial enliGHten are reported here.
Methods: The primary objectives of enliGHten were to evaluate the long-term safety and efficacy of treatment with lonapegsomatropin. enliGHten enrolled 298 participants from heiGHt and fliGHt. Results are reported through the participants’ final visit (study end date: December 31, 2022), including the subset (n=81) that completed lonapegsomatropin treatment because it was determined by the investigator that treatment for pediatric GHD was no longer necessary (referred to as “treatment completers”).
Results: By study end, there were 81 participants who had completed treatment with lonapegsomatropin for pediatric GHD as determined by investigator judgement as no longer necessary. Of these participants, 59.3% met or exceeded average parental height SDS. The difference between height SDS at last visit and average parental height SDS mean (SD) was 0.08 (0.69), and the mean (SD) height SDS was -0.36 (0.74) at last visit. Treatment completers had a mean age of 16.5 years at last visit (range, 13-18.6 years), their mean duration of treatment was 3.2 years (maximum duration of 5.3 years), and a mean (SD) lonapegsomatropin dose at last visit of 0.15 mg hGH/kg/week (range 0.04-0.27 mg hGH/kg/week). Consistent with these results, 53.4% of the total 298 participants had met or exceeded average parental height SDS by the end of the trial, despite the majority having not yet completed treatment for pediatric GHD at study end date. The mean treatment duration with lonapegsomatropin for all 298 participants through heiGHt, fliGHt and enliGHten trials was 4.1 years (maximum duration 6 years). The safety profile remained consistent with prior observations with no new signals.
Conclusion: Long-term safety was demonstrated in participants treated with lonapegsomatropin for pediatric GHD for up to 6 years. Furthermore, the majority of all participants, including those who by study end date had completed treatment with lonapegsomatropin, met or exceeded average parental height SDS without a mean dose increase over time.
21 Sep 2023 - 23 Sep 2023