Somatrogon: First Approval

Long-term effectiveness and safety of long-acting growth hormone preparation in children with growth hormone deficiency

OBJECTIVES

To evaluate the long-term effectiveness of weekly vs. daily growth hormone (GH) administration in children with GH deficiency.

METHODS

This study, part of the "LG Growth Study", included a total of 996 children with GH deficiency (773 receiving daily GH and 193 receiving weekly GH). Anthropometric data were collected at baseline and every 12 months; clinical and laboratory data were collected at baseline and throughout the study.

RESULTS

At baseline, the weekly GH group was older, shorter in mid-parental height (MPH), and had more pubertal boys compared to the daily GH group (age: 8.46 ± 3.44 vs. 7.46 ± 2.89 years, p<0.001; MPH: -0.88 ± 0.73 SD vs. -1.02 ± 0.84 SD, p=0.044; pubertal boys: 34.0 vs. 16.9 %, p=0.006). Height velocity and change in height SDS during the first 12 months were higher in the daily GH group (height velocity: 9.06 ± 1.72 vs. 8.67 ± 1.98 cm/year, p=0.028; height SDS change: 0.78 ± 0.39 vs. 0.61 ± 0.41, p<0.001). However, height SDS at 24 and 48 months were similar between groups. No significant differences in overall height velocity, annualized treatment continuation rate, and safety profile were observed over 48 months.

CONCLUSIONS

Weekly GH therapy appears to be an effective and safe alternative to daily GH treatment in children with GH deficiency over a 4-year period. Further research with larger sample sizes and longer follow-up is needed to confirm these findings and assess the extended safety and effectiveness of LAGH.

Somatrogon injection for the treatment of pediatric growth hormone deficiency with comparison to other LAGH products

INTRODUCTION

Somatrogon (NGENLA™) is a long-acting GH (LAGH) formulation that was approved in Canada in October 2021 for the treatment of pediatric growth hormone deficiency (GHD). Somatrogon has also received approval in Australia, Japan, the European Union, the USA, and the UK. Somatrogon is a glycoprotein that utilizes three copies of the C-terminal peptide of human chorionic gonadotropin to delay its clearance allowing for once-weekly administration.

AREAS COVERED

The purpose of this article is to describe the development of somatrogon for treatment of individuals with GHD. Trials of somatrogon demonstrated positive efficacy results in adults (Phase 2) and children (Phase 2 and 3) with GHD including non-inferiority of height velocity compared to daily GH, with no concerning side effects. Growth responses, pharmacodynamics and safety data are compared to other LAGH products, lonapegsomatropin and somapacitan, in Phase 3 trials in pediatric GHD.

EXPERT OPINION

New LAGH products, including somatrogon, have the potential to increase patient adherence as well as improve quality of life and clinical outcomes. Clinicians will need to identify the best candidates for LAGH therapy and understand how to safely monitor and adjust therapy. Long-term surveillance studies are necessary to demonstrate adherence, efficacy, cost-effectiveness, and safety of LAGH preparations.

Physician experience with once-weekly somatrogon versus once-daily rhGH regimen in pediatric patients with growth hormone deficiency: a cross-sectional survey of physicians from the global phase 3 study

Introduction

The standard of care for pediatric growth hormone deficiency (pGHD) is once-daily recombinant human growth hormone (rhGH). Somatrogon, a long-acting rhGH, requires less frequent, once-weekly, dosing. We describe physicians' preference for, experiences, and satisfaction with once-weekly somatrogon vs once-daily rhGH.

Methods

English-speaking investigators from somatrogon's global phase III study (NCT02968004) with prior experience using once-daily rhGH were included. Participants answered an online survey containing 14 closed- and open-ended items.

Results

Twenty-four pediatric endocrinologists (41.7% men; 79.2% practiced at public/private hospitals) from 12 countries with 25.8 ± 12.0 years' experience treating pGHD completed the survey. In terms of the time and effort required to explain device instructions, injection regimen, procedure for missed injection, and address patients'/caregivers' concerns, a similar proportion of physicians chose once-weekly somatrogon and once-daily rhGH; 62.5% physicians indicated that once-daily rhGH required greater effort to monitor adherence. Overall, 75% preferred once-weekly somatrogon over once-daily rhGH, 79.2% considered once-weekly somatrogon to be more convenient and less burdensome, and 83.3% were likely to prescribe somatrogon in the future. Overall, 50% felt that once-weekly somatrogon was more beneficial to patients, while 50% chose "No difference". Most physicians (62.5%) felt both regimens were equally likely to support positive long-term growth outcomes and reduce healthcare utilization. More physicians were "very satisfied" with once-weekly somatrogon (62.5%) than with once-daily rhGH (16.7%). Reduced injection frequency, patient and caregiver burden, increased convenience, and improved adherence were reasons for these choices.

Conclusion

Physicians had a positive experience with, and perception of, treating pGHD with once-weekly somatrogon.

Long-term Pegylated GH for Children With GH Deficiency: A Large, Prospective, Real-world Study

CONTEXT

The evidence of long-term polyethylene glycol recombinant human GH (PEG-rhGH) in pediatric GH deficiency (GHD) is limited.

OBJECTIVE

This study aimed to examine the effectiveness and safety of long-term PEG-rhGH in children with GHD in the real world, as well as to examine the effects of dose on patient outcomes.

DESIGN

A prospective, observational, posttrial study (NCT03290235).

SETTING, PARTICIPANTS AND INTERVENTION

Children with GHD were enrolled from 81 centers in China in 4 individual clinical trials and received weekly 0.2 mg/kg/wk (high-dose) or 0.1 to <0.2 mg/kg/wk (low-dose) PEG-rhGH for 30 months.

MAIN OUTCOMES MEASURES

Height SD score (Ht SDS) at 12, 24, and 36 months.

RESULTS

A total of 1170 children were enrolled in this posttrial study, with 642 patients in the high-dose subgroup and 528 in the low-dose subgroup. The Ht SDS improved significantly after treatment in the total population (P < 0.0001), with a mean change of 0.53 ± 0.30, 0.89 ± 0.48, 1.35 ± 0.63, 1.63 ± 0.75 at 6 months, 12 months, 24 months, and 36 months, respectively. In addition, the changes in Ht SDS from baseline were significantly improved in the high-dose subgroup compared with the low-dose subgroup at 6, 12, 24, and 36 months after treatment (all P < 0.05). A total of 12 (1.03%) patients developed serious adverse events. There was no serious adverse event related to the treatment, and no AEs leading to treatment discontinuation or death occurred.

CONCLUSIONS

PEG-rhGH showed long-term effectiveness and safety in treating children with GHD. Both dose subgroups showed promising outcomes, whereas PEG-rhGH 0.2 mg/kg/wk might show additional benefit.

Growth Hormone Deficiency following Traumatic Brain Injury in Pediatric and Adolescent Patients: Presentation, Treatment, and Challenges of Transitioning from Pediatric to Adult Services

Traumatic brain injury (TBI) is increasingly recognized, with an incidence of approximately 110 per 100,000 in pediatric populations and 618 per 100,000 in adolescent and adult populations. TBI often leads to cognitive, behavioral, and physical consequences, including endocrinopathies. Deficiencies in anterior pituitary hormones (e.g., adrenocorticotropic hormone, thyroid-stimulating hormone, gonadotropins, and growth hormone [GH]) can negatively impact health outcomes and quality of life post-TBI. This review focuses on GH deficiency (GHD), the most common post-TBI pituitary hormone deficiency. GHD is associated with abnormal body composition, lipid metabolism, bone mineral density, executive brain functions, behavior, and height outcomes in pediatric, adolescent, and transition-age patients. Despite its relatively frequent occurrence, post-TBI GHD has not been well studied in these patients; hence, diagnostic and treatment recommendations are limited. Here, we examine the occurrence and diagnosis of TBI, retrospectively analyze post-TBI hypopituitarism and GHD prevalence rates in pediatric and adolescent patients, and discuss appropriate GHD testing strategies and GH dosage recommendations for these patients. We place particular emphasis on the ways in which testing and dosage recommendations may change during the transition phase. We conclude with a review of the challenges faced by transition-age patients and how these may be addressed to improve access to adequate healthcare. Little information is currently available to help guide patients with TBI and GHD through the transition phase and there is a risk of interrupted care; therefore, a strength of this review is its emphasis on this critical period in a patient's healthcare journey.

Safety and Efficacy of Lonapegsomatropin in Children With Growth Hormone Deficiency: enliGHten Trial 2-Year Results

PURPOSE

The objectives of the ongoing, Phase 3, open-label extension trial enliGHten are to assess the long-term safety and efficacy of weekly administered long-acting growth hormone lonapegsomatropin in children with growth hormone deficiency.

METHODS

Eligible subjects completing a prior Phase 3 lonapegsomatropin parent trial (heiGHt or fliGHt) were invited to participate. All subjects were treated with lonapegsomatropin. Subjects in the United States switched to the TransCon hGH Auto-Injector when available. Endpoints were long-term safety, annualized height velocity, pharmacodynamics [insulin-like growth factor-1 SD score (SDS) values], and patient- and caregiver-reported assessments of convenience and tolerability.

RESULTS

Lonapegsomatropin treatment during enliGHten was associated with continued improvements in height SDS through week 104 in treatment-naïve subjects from the heiGHt trial (-2.89 to -1.37 for the lonapegsomatropin group; -3.0 to -1.52 for the daily somatropin group). Height SDS also continued to improve among switch subjects from the fliGHt trial (-1.42 at fliGHt baseline to -0.69 at week 78). After 104 weeks, the average bone age/chronological age ratio for each treatment group was 0.8 (0.1), showing only minimal advancement of bone age relative to chronological age with continued lonapegsomatropin treatment among heiGHt subjects. Fewer local tolerability reactions were reported with the TransCon hGH Auto-Injector compared with syringe/needle.

CONCLUSIONS

Treatment with lonapegsomatropin continued to be safe and well-tolerated, with no new safety signals identified. Children treated with once-weekly lonapegsomatropin showed continued improvement of height SDS through the second year of therapy without excess advancement of bone age.