ResearchPad - understanding-and-treating-pediatric-growth-disorders Default RSS Feed en-us © 2020 Newgen KnowledgeWorks <![CDATA[OR10-04 Interpretation of Insulin-like Growth Factor-1 (IGF-1) Levels Following Administration of Somatrogon (a Long-acting Human Growth Hormone - hGH-CTP)]]> IGF-1 is often used as a biomarker to evaluate the efficacy and safety of hGH replacement therapy. Typically, the mean IGF-1 SDS level during the dosing interval, rather than the peak value, guides clinical decision-making: sustained mean values > +2 may require hGH dose modifications. With long-acting formulations (administered weekly), the IGF-1 evaluation paradigm needs to take into account when the sample was obtained relative to the last administered dose. Previous studies with OPKO’s once weekly Somatrogon (hGH-CTP), demonstrated that IGF-1 SDS peaked ~ 48 hours post-dose and that values at ~ 96 hours best approximated the mean IGF-1 SDS throughout the dosing interval [1]. Data from the pivotal Phase 3 non-inferiority study comparing treatment with Somatrogon to Genotropin allowed further evaluation of the IGF-1 SDS analysis paradigm.

Enrolled subjects were randomized to receive treatment with either once weekly Somatrogon (0.66 mg/kg; N=109) or once daily Genotropin (0.034 mg/kg; N=115). IGF1 was sampled ~ five times during 52 weeks of treatment with Somatrogon, providing a total of 557 samples obtained after the first dose of Somatrogon. IGF-1 SDS values were calculated using Bidlingmaier’s equations [2].

Analysis of IGF-I SDS data from the Phase 3 study showed that the previously-developed model, with adjustments to two parameters (baseline IGF-1, EC50) and adapted to fit IGF-1 values in the absence of Somatrogon concentration data, fit the IGF-1 data for Somatrogon with minimal bias. This allowed prediction of IGF-1 SDS values at timepoints throughout the dosing interval as well as calculation of the mean value during a dosing interval. Of the samples obtained between 48–72 hours post-dose (representing peak IGF-1 SDS), approximately 17% had an IGF1 SDS > +2. At 96 hours (corresponding to mean IFG-1 SDS), fewer than 2% of modeled values were > +2. Mean IGF-1 SDS over the dosing interval was between -1 and +1 for all subjects.

These findings indicate that IGF-1 SDS values need to be interpreted in the context of when the sample was obtained relative to the last dose of Somatrogon. Our results indicate that samples obtained 96 hours post-dose best represent mean IGF-1 levels and that values obtained between 48–72 hours post-dose represent values closer to peak IGF-1 concentrations. In our Phase 3 study, of the 557 samples collected from 114 patients during the 12-month Somatrogon treatment period, fewer than 2% of the corresponding values at 96 hours postdose (estimated from a pharmacokinetic/pharmacodynamic model) had IGF-1 SDS levels > +2.

1. Fisher DM, et al. Horm Res Paediatr 2017;87:324. 2. Bidlingmaier M, et al. J Clin Endocrinol Metab 2014;99:1712

<![CDATA[OR10-06 Somatrogon Growth Hormone in the Treatment of Pediatric Growth Hormone Deficiency: Results of the Pivotal Pediatric Phase 3 Clinical Trial]]> Background: Somatrogon (hGH-CTP) is a long acting recombinant human growth hormone (rhGH; somatropin) in development for once weekly treatment of children with growth hormone deficiency (GHD). Somatrogon contains the amino acid sequence of hGH and three copies of the carboxy-terminal peptide (CTP) derived from human chorionic gonadotropin. A 12 month phase 2 trial of once weekly Somatrogon vs daily Genotropin in children with GHD demonstrated that 0.66 mg/kg/wk of Somatrogon had a similar benefit - risk profile as 0.24 mg/kg/wk of Genotropin. The open label extension of this phase 2 study has generated an additional 5 years of longitudinal efficacy and safety data with this dose. This report summarizes top line results from a pivotal phase 3 global trial ( NCT02968004) designed to investigate the non-inferiority of once weekly Somatrogon hGH-CTP compared to daily hGH after 12 months in treatment-naive prepubertal children with GHD. Methods: The Phase 3 trial enrolled 224 subjects who were randomized in a 1:1 ratio to receive either once weekly Somatrogon hGH-CTP (0.66 mg/kg) or once daily Genotropin (0.24 mg/kg/wk) for 12 months. Randomization was stratified by geographic region, peak GH level and age. The primary endpoint of the study was height velocity (HV) at month 12; secondary endpoints included HV at month 6, change in height SDS at month 6 and 12, IGF-1 and IGF-I SDS, immunogenicity, and safety. Results: At baseline, the mean (SD) age and height SDS of the somatrogon (N=109, 75.2% male) and Genotropin (N=115, 68.7% male) groups were 7.83 (2.66) and -2.94 (1.29) and 7.61 (2.37) and -2.78 (1.27), respectively. One subject in each group discontinued during the 12 month study, and 95% of the completers continued into an open-label extension study. At month 12, mean HV was 10.12 cm/yr in the Somatrogon group and 9.78 cm/yr in the Genotropin group, with the treatment difference of 0.33 cm/year favoring Somatrogon. The lower bound of the two-sided 95% confidence interval of the treatment difference was -0.39, which was higher than the pre-established non-inferiority margin and demonstrated non-inferiority of once weekly somatrogon vs daily Genotropin therapy. Height velocity at month 6 (10.60 cm/yr vs 10.04 cm/yr), change in height SDS at months 6 (0.54 vs 0.48) and 12 (0.92 vs 0.87) were likewise numerically higher in the Somatrogon-treated cohort. The majority of adverse events were mild to moderate in severity (somatrogon: 78.9%, Genotropin: 79.1%) and, overall, weekly somatrogon was generally well-tolerated and comparable to daily Genotropin. Conclusion: Top-line results from the pivotal phase 3 trial demonstrate that Somatrogon (hGH-CTP) given once weekly by sc injection is non-inferior to Genotropin (hGH) given once daily and that once weekly somatrogon administration was generally well-tolerated in patients with pGHD.

<![CDATA[OR10-02 Diagnosis of Severe GH Deficiency in Newborns: New Reference Range for the Preterm and Confirmation of the GH Cut-Off]]> <![CDATA[OR10-01 Mild Maternal Sleep Disordered Breathing in Pregnant Women Affects Growth Patterns of Head Circumference and Adiposity During the First Three Years of Life]]> <![CDATA[OR10-05 Phase 3 FliGHt Trial: Experience of Switching from Daily Growth Hormone Therapy to Once-Weekly TransCon HGH in Children with Growth Hormone Deficiency]]>