Weekly somatrogon vs daily somatropin: a propensity score-matched analysis of growth outcomes from clinical data vs...

Somatrogon is a long-acting growth hormone utilized for treatment of pediatric patients with growth hormone deficiency (GHD). This matched cohort analysis compared the first 3 years of height outcomes for somatrogon-treated patients from a Phase 3 somatrogon study (NCT02968004) with historical data from somatropin-treated patients in the Kabi/Pfizer International Growth Study (KIGS).

In the somatrogon study, patients with GHD were randomized to once-weekly somatrogon (0.66 mg/kg/week) or once-daily somatropin (0.24 mg/kg/week) for 12 months, followed by an open-label extension, during which all patients received somatrogon (0.66 mg/kg/week or lower dose as per protocol). Patients in the somatrogon study (somatrogon cohort) were matched with patients with GHD from KIGS (KIGS cohort) who had received somatropin (0.20-0.30 mg/kg/week), using propensity score matching according to baseline characteristics of geographic region, gender, age, peak GH, and height standard deviation score (HtSDS) (ie, peak GH and HtSDS at study entry).

155 patients in the somatrogon study were matched to 155 somatropin-treated patients from KIGS. The somatrogon and KIGS cohorts had similar mean annualized height velocity through Years (Y) 1 to 3 of treatment (Y1: 10.03 vs 9.57; Y2: 7.70 vs 7.33; Y3: 7.15 vs 6.56). Mean changes in HtSDS (from baseline) through Y1-3 were comparable between both cohorts, though the somatrogon cohort appeared to have larger changes in Y2-3.

Somatrogon-treated patients in the Phase 3 study had similar height outcomes compared with matched somatropin-treated patients in KIGS, strengthening the expectation that once-weekly somatrogon will have comparable efficacy to somatropin in real-world treatment of pediatric patients with GHD.