Up to 5 years of weekly somatrogon in children with growth hormone deficiency: final data from the global phase 3 study.
Once-weekly somatrogon shows sustained efficacy in height velocity for children with growth hormone deficiency, but the long-term clinical implications remain uncertain.
Where it sits
this study against the rest of the hgh (somatropin) corpusSummary and findings
This study evaluated the long-term efficacy and safety of once-weekly somatrogon in pediatric patients with growth hormone deficiency after up to 5 years of treatment. A total of 212 patients participated, receiving a dose of 0.66 mg/kg/week. The study reported annualized height velocity and adverse events over the treatment period.
Abstract
<h4>Purpose</h4>This open-label extension (OLE) study aimed to evaluate the long-term efficacy and safety of once-weekly somatrogon in pediatric patients with growth hormone deficiency (GHD) following up to 5 years of somatrogon treatment.<h4>Methods</h4>Patients who had previously completed 12 months of treatment (somatrogon or somatropin) in a phase 3, randomized, active-controlled study (NCT02968004) were eligible to enroll into this OLE study; somatropin-treated patients were switched to somatrogon (0.66 mg/kg/week), and somatrogon-treated patients received somatrogon at their previous dose.<h4>Results</h4>A total of 212 patients entered the OLE. Mean annualized height velocity at the end of OLE Year 1 (Y1), Y2, Y3, and Y4 was 8.11, 7.91, 7.02, and 6.56 cm/year, respectively. Mean height SDS increased in each year of the OLE and approached 0 SDS by OLE Y4. Mean (SD) IGF-I SDS was positive and within the normal range throughout the OLE. The incidence of adverse events (AEs) was 53.8% to 72.3%, with most being mild to moderate. The incidence of serious AEs in each year was low (0-4.7%), and none were related to treatment. The most common treatment-related AEs were injection-site pain and injection-site erythema. The presence of antidrug antibodies did not appear to impact safety or efficacy outcomes.<h4>Conclusion</h4>Based on the final data from the largest cohort of somatrogon-treated patients to date, once-weekly somatrogon demonstrated sustained efficacy and an acceptable safety profile during the OLE period. Once-weekly somatrogon constitutes a valuable long-term alternative to once-daily somatropin, offering potentially improved adherence and treatment outcomes.
Background
This paper addresses the long-term effects of somatrogon, a growth hormone therapy, in children with growth hormone deficiency (GHD). Prior studies have shown short-term efficacy of growth hormone therapies, but long-term data are limited. Understanding the sustained efficacy and safety profile of somatrogon is crucial for informing treatment decisions in pediatric patients with GHD.
Methods
This was an open-label extension study involving patients who previously completed 12 months of treatment in a phase 3 randomized controlled study. A total of 212 patients were enrolled, receiving somatrogon at a dose of 0.66 mg/kg/week. The primary outcome measures included annualized height velocity and safety assessments over a follow-up period of up to 5 years.
Results
The mean annualized height velocity at the end of OLE Year 1 was 8.11 cm/year, Year 2 was 7.91 cm/year, Year 3 was 7.02 cm/year, and Year 4 was 6.56 cm/year. The mean height SDS increased each year and approached 0 SDS by OLE Year 4. The incidence of adverse events ranged from 53.8% to 72.3%, with serious adverse events occurring at a rate of 0% to 4.7%.
Interpretation
The findings suggest that somatrogon may provide sustained growth benefits in children with GHD, although the clinical significance of the observed height velocities should be interpreted cautiously. The study's open-label design and lack of a control group limit the ability to draw definitive conclusions regarding the treatment's efficacy and safety. Further studies with controlled designs are warranted to confirm these findings.
Key findings
- Mean annualized height velocity at OLE Year 1 was 8.11 cm/year, Year 2 was 7.91 cm/year, Year 3 was 7.02 cm/year, and Year 4 was 6.56 cm/year.
- Mean height SDS approached 0 SDS by OLE Year 4.
- The incidence of adverse events (AEs) ranged from 53.8% to 72.3%, with most being mild to moderate.
- The incidence of serious AEs in each year was low, ranging from 0% to 4.7%, and none were related to treatment.
- The most common treatment-related AEs were injection-site pain and injection-site erythema.
Limitations
- Open-label design may introduce bias.
- No control group in the extension phase.
- Potential confounding factors in reporting adverse events.
- Long-term follow-up may not capture all safety concerns.