Poster Presentation ESA-SRB-APEG-NZSE 2022

Efficacy and safety of once-weekly somatrogon vs once-daily Genotropin in Asian subjects: post-hoc subgroup analysis of the pivotal phase 3 study (#448)

Roy Gomez 1 , Vaman Khadilkar 2 , Jayashri Shembalkar 3 , Der-Ming Chu 4 , Cheol Woo Ko 5 , Michael P Wajnrajch 6 7 , Ronnie Wang 8
  1. Pfizer Pte Ltd, Singapore
  2. Hirabai Cowasji Jehangir Medical Research Institute, Jehangir Hospital, Pune, MH, India
  3. Endocrine Section, Getwell Hospital, Nagpur, India
  4. Department of Pediatrics, Tri-Service General Hospital, National Defense Medical Center, Taipei, Taiwan (R.O.C.)
  5. Kyungpook National University Children’s Hospital, Daegu, South Korea
  6. Pfizer Inc, New York, NY, USA
  7. New York University Grossman School of Medicine, New York, NY, USA
  8. Pfizer Inc, Groton, CT, USA

Somatrogon, a long-acting recombinant human growth hormone (GH), is approved in several countries as a once-weekly treatment for children with pediatric GH deficiency (GHD). A global phase 3 study in pediatric subjects with GHD compared the efficacy and safety of once-weekly somatrogon with once-daily Genotropin. This post hoc subgroup analysis evaluated the efficacy and safety of once-weekly somatrogon vs once-daily Genotropin in Asian subjects.

The open-label phase 3 study randomized 224 subjects 1:1 to receive either once-weekly somatrogon (0.66 mg/kg/week) or once-daily Genotropin (0.24 mg/kg/week) for 12 months. Randomization was stratified by geographic region, peak GH level, and age. The primary endpoint was height velocity (HV) at month 12. This subgroup analysis included 45 Asian subjects from Australia, Great Britain, India, New Zealand, South Korea, Spain, Taiwan, and the USA.

Both treatment subgroups (somatrogon: n=24; Genotropin: n=21) had similar demographic and baseline characteristics. Least squares mean HV at month 12 in the somatrogon and Genotropin group was 10.94 cm/year and 9.56 cm/year, respectively, with a treatment difference of 1.38 (confidence interval [CI]: -0.14‑2.89) favoring somatrogon. The lower bound of the two-sided 95% CI of the treatment difference (somatrogon-Genotropin) was −0.14 for this subgroup. This was similar to that for the overall study population (−0.24), in which the efficacy of once-weekly somatrogon was demonstrated to be non-inferior to once-daily Genotropin. The efficacy outcomes of this post hoc analysis are presented below (Table). Adverse events were reported in 83.3% of subjects in the somatrogon group and 76.2% of subjects in the Genotropin group. Serious adverse events were recorded for one and two subjects in the somatrogon and Genotropin groups, respectively.

The efficacy and safety results from this analysis of Asian subjects are similar to the overall study population, in which non-inferiority of once-weekly somatrogon to once-daily Genotropin was statistically demonstrated.

Clinicaltrials.gov:NCT02968004

62feeda51771c-Asian_subjects_TABLE.PNG