Sogroya's EU ISS First-Mover Win: Regulatory Milestone Meets Unproven Payer Path

CHMP Recommends Once-Weekly Sogroya for Idiopathic Short Stature in EU

Novo Nordisk has received a positive opinion from the Committee for Medicinal Products for Human Use (CHMP) of the European Medicines Agency (EMA) for once-weekly Sogroya® (somapacitan) for children in Europe with idiopathic short stature (ISS) with persistent growth disturbance. If approved by the European Commission, Sogroya would be the first and only growth hormone treatment for ISS in the EU, a condition affecting up to 3% of children worldwide. This recommendation follows previous positive CHMP opinions for Sogroya in children born Small for Gestational Age (SGA) and with Noonan Syndrome (NS) in May 2026. The European Commission's decision on marketing authorisation, covering all three indications, is expected later this year, supported by Phase 3 REAL8 clinical trial data demonstrating non-inferiority to once-daily growth hormone treatment.

• The positive CHMP opinion for Sogroya in idiopathic short stature (ISS) marks a significant regulatory milestone for Novo Nordisk. If approved by the European Commission, Sogroya would become the first and only once-weekly growth hormone treatment specifically for ISS in the EU. This addresses a critical unmet need, as ISS affects up to 3% of children worldwide and currently has limited approved treatment options, potentially transforming care for affected children and their families.
• The CHMP's recommendation is supported by robust data from the Phase 3 REAL8 clinical trial. This study demonstrated that once-weekly Sogroya (somapacitan) was non-inferior to once-daily growth hormone treatment in achieving mean annualised height velocity at Week 52 in children with idiopathic short stature, as well as those born small for gestational age and with Noonan Syndrome. This clinical evidence underscores Sogroya's efficacy and convenience as a long-acting growth hormone analogue.
• This positive opinion expands Sogroya's potential utility, building on previous CHMP recommendations in May 2026 for short stature in children born Small for Gestational Age (SGA) and with Noonan Syndrome (NS). The anticipated marketing authorisation from the European Commission will cover all three indications, offering a comprehensive treatment solution for various growth disorders. This multi-indication approval highlights Novo Nordisk's commitment to addressing diverse paediatric growth challenges and improving patient quality of life.

Addressing Key Challenges in Idiopathic Short Stature Treatment

Treatment of ISS with persistent growth disturbance involves multiple pharmacological strategies, each carrying distinct efficacy constraints, safety considerations, and practical limitations. The interplay between pubertal timing, bone age advancement, and therapeutic windows makes optimizing outcomes particularly complex for clinical and strategic teams.

• Bone age acceleration limits the GH treatment window. The relentless tempo of bone age advancement driven by sex steroids — with estrogen principally modulating epiphyseal fusion in both females and males — significantly hinders the impact of GH therapy by restricting the time available for linear growth.

• Age at treatment initiation is a critical determinant of outcome. In GH-treated children with ISS, adult height correlates negatively with age at GH start. Baseline age was identified as the only clinically significant predictor of first-year growth response (R-squared, 6.4%), underscoring that delayed initiation substantially reduces height gain potential.

• GH dose escalation carries metabolic risks. At dosages ≥ 0.3 mg/kg/week, a dose-dependent increase in mean fasting and stimulated insulin levels is observed. High-dose GH use can raise insulin-like growth factor I concentrations supraphysiologically, and the possibility of delayed post-treatment effects of hyperinsulinemia and/or heightened GH and IGF-1 exposure on cancer risk warrants caution and ongoing scrutiny of risks versus benefits.

• Aromatase inhibitor efficacy in ISS remains unestablished for adult height. Two years of letrozole therapy did not increase predicted adult height in pre- and peripubertal boys with ISS when re-assessed 4 years after the treatment period. Additionally, letrozole-treated boys with ISS were noted to have more vertebral abnormalities than a placebo group, and adult height data are still lacking across the broader pediatric AI-treated population.

• GnRHa use renders adolescents temporarily hypogonadal. When gonadotropin-releasing hormone analogs are used in combination with GH to suppress physiologic puberty and increase height potential, they render adolescents temporarily hypogonadal at a critical time in development — a meaningful trade-off that must be weighed against the growth benefit.

• Adherence to daily injection regimens is suboptimal. Treatment adherence with daily recombinant human GH remains suboptimal owing to the burden of daily injections, which can compromise long-term therapeutic outcomes in a condition already requiring sustained intervention.

• Injection-site adverse effects require vigilant monitoring. Localized lipoatrophy has been observed with long-acting GH formulations, including a reported recurrence within eight weeks when site rotation instructions were not followed, highlighting the need for clinician vigilance and patient/caregiver education in monitoring and addressing adverse effects promptly.

Sogroya's Potential to Redefine ISS Treatment in Europe

Idiopathic short stature (ISS) is defined by a height standard deviation score below −2.25 (corresponding to below the 1.2nd percentile), a normal growth hormone response during stimulation tests (>10 ng/ml), and the absence of identifiable causes such as growth hormone deficiency, Turner syndrome, small for gestational age status, dysmorphology syndromes, or chronic childhood diseases. The standard pharmacological approach centers on recombinant human growth hormone (rhGH) therapy, with the goals of achieving a normal height and normal growth rate during childhood. In the United States, rhGH is approved for ISS treatment, and dosages of 0.24–0.37 mg/kg/week have been shown not to adversely affect blood glucose levels, though a dose-dependent increase in mean fasting and stimulated insulin levels is observed at dosages ≥0.3 mg/kg/week. Current evidence from on-treatment surveillance studies suggests rhGH does not increase the risk for new malignancies in children with ISS at doses ≤0.37 mg/kg/week, though caution is warranted given a continuing trend toward dose escalation and the possibility of delayed post-treatment effects of hyperinsulinemia and heightened GH and insulin-like growth factor I exposure on cancer risk.

Optimization of rhGH dosing regimens remains an active area of clinical investigation. A 4-year, open-label, multicenter, randomized trial comparing individualized, formula-based dosing of Genotropin® versus standard weight-based dosing demonstrated that subjects across all treatment regimens achieved similar average height gains of +1.3 SDS, but the individualized dosing regimen utilized less GH to achieve an equivalent height gain, supporting a more cost-effective approach. More recently, once-weekly pegylated recombinant human GH (PEG-rhGH) has been evaluated as an alternative to daily rhGH. A systematic review and meta-analysis of eight studies comprising 2,549 children found that once-weekly PEG-rhGH demonstrated comparable short-term growth outcomes to daily rhGH at 6 and 12 months, with modest but significant superiority in height SDS (MD = 0.10, 95% CI 0.01–0.19) and height velocity (MD = 0.74 cm/year, 95% CI 0.42–1.05) by 24 months. Safety analyses revealed no increase in adverse or serious adverse events with PEG-rhGH compared to daily rhGH, with reactions generally mild and transient.

Aromatase inhibitors (AIs) represent an adjunctive strategy under investigation, particularly in male patients, based on the principle that bone age advancement is estrogen-dependent. A meta-analysis of eight randomized controlled trials comprising 433 participants found that the addition of AIs to rhGH, compared with rhGH alone, resulted in higher growth velocity (WMD: 3.19 cm/year; 95% CI: 2.75–3.63; P < 0.001), higher predicted adult height (WMD: 5.50 cm; 95% CI: 3.52–7.49; P < 0.001), and younger bone age (WMD: −0.80 years; 95% CI: −1.06 to −0.54; P < 0.001), with no significant difference in the risk of adverse events between groups (OR: 1.08; 95% CI: 0.44–2.66; P = 0.873). However, final adult height data from AI trials remain scarce, and several safety issues remain inadequately studied, meaning AI use in ISS has not yet been established as a standard of care. Additionally, primary IGF-1 deficiency — defined by low IGF-1 levels without GH deficiency — is identified in 28% of children with ISS, representing a distinct subpopulation whose optimal management within current treatment frameworks warrants further characterization.

REAL8 Trial Data Supporting Sogroya's CHMP Opinion

Two key trials have examined therapeutic strategies for idiopathic short stature (ISS) in pubertal boys, evaluating aromatase inhibitors (AIs), recombinant human growth hormone (rhGH), and their combination. The trials differ in design rigor and population size but converge on height gain and predicted adult height as primary endpoints.

Sogroya's EU Nod: A New Era for Pediatric Short Stature Treatment

The recent positive opinion from the CHMP for Novo Nordisk's once-weekly Sogroya (somapacitan) for children with idiopathic short stature (ISS) signals a pivotal moment in the management of pediatric growth disorders. This recommendation, if followed by European Commission approval, would introduce the first and only once-weekly growth hormone treatment for ISS in the EU, a condition affecting a significant number of children globally. The clinical literature consistently highlights the substantial treatment burden associated with daily growth hormone injections, which can impact adherence and overall patient experience. Sogroya's once-weekly administration directly addresses this challenge, offering a more convenient option that could significantly improve the quality of life for children and their families.

Phase 3 REAL8 clinical trial data, which underpinned this positive opinion, demonstrated that once-weekly somapacitan achieved non-inferiority to daily growth hormone in terms of efficacy for ISS, and even showed superiority in height velocity for Noonan Syndrome, while maintaining comparable safety profiles across multiple indications including Small for Gestational Age (SGA) and Turner Syndrome. This robust evidence supports the potential for Sogroya to become a new standard of care.

However, as with any novel therapy, certain considerations remain important for long-term success and patient safety:

• Sustained Safety Monitoring: While short-term safety is reassuring, the long-term safety profile of once-weekly somapacitan, particularly concerning rare adverse events observed with daily rhGH over extended periods, will require ongoing vigilance through post-marketing surveillance.

• IGF-I Management: The pharmacodynamic profiles indicate dose-dependent increases in IGF-I. Careful monitoring of IGF-I levels will be essential to ensure optimal therapeutic effect while avoiding potential complications from sustained supraphysiological levels.

• Evolving Competitive Landscape: While Sogroya currently holds a first-mover advantage for a weekly ISS indication, other long-acting growth hormone derivatives are in development. Future competition could emerge, necessitating continued innovation and differentiation.

Ultimately, this development represents a significant step forward in pediatric endocrinology, offering a much-needed, less burdensome treatment option that could enhance adherence and improve growth outcomes for a broad population of children with short stature.