Open-Label 9-Year Follow-Up Extension Phase 2 Study of Once-Weekly Somatrogon in Children With Growth Hormone...

Area of Science:

• Pediatric endocrinology
• Pharmacology
• Clinical research

Background:

• Growth hormone deficiency (GHD) presents significant growth and developmental challenges in children, requiring sustained therapeutic intervention.
• Once-weekly somatrogon, a long-acting recombinant human growth hormone analogue, is approved for pediatric GHD treatment.

Purpose of the Study:

• To evaluate the long-term safety and efficacy of once-weekly somatrogon in pediatric patients diagnosed with GHD.
• To assess growth outcomes and adverse events over an extended treatment period.

Main Methods:

• An open-label extension (OLE) study followed an initial 12-month phase 2 study.
• Forty-eight children with GHD received once-weekly somatrogon for up to nine years.
• Safety was monitored via adverse events, antidrug antibodies (ADAs), and injection site reactions; efficacy was assessed by height velocity (HV) and height standard deviation scores (SDS).

Main Results:

• Treatment-emergent adverse events decreased from 52.1% in year 1 to 23.8% by year 9; serious adverse events were rare.
• Antidrug antibodies were detected, but no neutralizing antibodies were found, and ADA presence did not impact efficacy or safety.
• Mean annualized HV remained above 5 cm/year, and height SDS improved significantly from -4.0 to -0.2 over the study period.

Conclusions:

• Once-weekly somatrogon demonstrates favorable long-term safety and efficacy as a treatment for pediatric GHD.
• The treatment is well-tolerated and supports sustained growth, representing a viable therapeutic option.
• Further real-world data collection is recommended to complement existing findings.