Perception of Treatment Burden With Once Weekly Somatrogon vs Once Daily Genotropin in Pediatric Patients With Growth Hormone Deficiency (GHD): Results From a Randomized Phase 3 Study
Authors: Maniatis Aristides K , Carakushansky Mauri , Galcheva Sonya , Prakasam Gnanagurudasan , Fox Larry A , Dankovcikova Adriana , Loftus Jane , Palladino Andrew A , Resa Maria de los Angeles , Taylor Carrie Turich , Dattani Mehul T , Lebl Jan 
Published: May 2021

Background: Somatrogon is a long-acting recombinant human growth hormone (rhGH) comprised of the amino acid sequence of hGH and 3 copies of the carboxy-terminal peptide from human chorionic gonadotropin. Somatrogon is being developed as a once weekly subcutaneous (SC) injectable treatment for pediatric patients (pts) with GHD.

Aims: To evaluate patient and caregiver perceptions of the treatment burden associated with a once weekly somatrogon SC injection schedule compared with a once daily Genotropin SC injection schedule.

Methods: In this phase 3 (NCT03831880), open-label, crossover study, pediatric pts (3 to &lt;18 years) with GHD on at least 3 months stable rhGH therapy were randomized 1:1 to receive treatment according to 1 of 2 sequences: Sequence #1, 12 weeks of Genotropin once daily followed by 12 weeks of somatrogon once weekly; Sequence #2, 12 weeks of somatrogon once weekly followed by 12 weeks of Genotropin once daily. The primary objective of the study was to evaluate treatment burden assessed as the difference between mean overall Life Interference (LI) total scores after each 12-week treatment period of weekly somatrogon and daily Genotropin. Secondary objectives further assessed treatment experience of pts and caregivers after each treatment period and their comparison of both treatments at the end of the study. A recently developed, validated dyad questionnaire (Turner-Bowker DM et al, 2020) was administered as an electronic Patient Reported Outcome to collect all assessments.

Results: Eighty-seven pts were randomized to Sequence #1 (n=43) or Sequence #2 (n=44) with 85 pts completing the study. Somatrogon administered as a once weekly injection had a lower (statistically significant) treatment burden than Genotropin administered as a once daily injection, based on the mean overall LI total scores after somatrogon (8.63) vs Genotropin (24.13) treatment (mean difference: -15.49; two-sided 95% CI: [-19.71, -11.27]; P &lt;0.0001). Compared with once daily Genotropin, once weekly somatrogon was associated with greater convenience, higher satisfaction with treatment experience, and less life interference for the caregiver. A higher proportion of pts preferred once weekly somatrogon and demonstrated a greater intent to comply with treatment. The proportion of pts who experienced at least one treatment-emergent adverse event (TEAE) with Genotropin and somatrogon treatment were 44.2% and 54.0%, respectively. Injection site pain was the most common TEAE during the Genotropin (12.8%) and somatrogon (14.9%) treatment periods and was rated as mild in most cases. No severe or serious adverse events were reported.

Conclusions: In pediatric pts with GHD, compared with Genotropin administered once daily, somatrogon administered once weekly has a lower treatment burden as shown by less life interference, and is associated with a more favorable treatment experience.