Weekly somatrogon vs daily somatropin: a propensity score-matched analysis of growth outcomes from clinical data vs KIGS.
Somatrogon-treated patients showed similar height outcomes compared to those treated with daily somatropin over three years, suggesting comparable efficacy in real-world settings.
Where it sits
this study against the rest of the hgh (somatropin) corpusSummary and findings
This study compared height outcomes in pediatric patients with growth hormone deficiency treated with weekly somatrogon versus daily somatropin. The analysis included 155 matched patients from each cohort over a 3-year period. Both treatments showed similar mean annualized height velocity and changes in height standard deviation scores.
Abstract
Objectives 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). Methods 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). Results 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. Conclusion 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.
Background
This paper addresses the efficacy of somatrogon, a long-acting growth hormone, in pediatric patients with growth hormone deficiency (GHD). Previous studies have shown that daily somatropin is effective for GHD, but the long-term outcomes of weekly somatrogon compared to daily administration are less understood. This study is significant as it utilizes a matched cohort analysis to compare real-world outcomes between these two treatment regimens.
Methods
The study utilized a matched cohort design, comparing 155 patients treated with somatrogon (0.66 mg/kg/week) from a Phase 3 study to 155 patients treated with somatropin (0.20-0.30 mg/kg/week) from the Kabi/Pfizer International Growth Study (KIGS). The duration of the initial treatment was 12 months, followed by an open-label extension. Primary outcomes included mean annualized height velocity and changes in height standard deviation scores over three years.
Results
The primary endpoint showed that the mean annualized height velocity for the somatrogon cohort was 10.03 cm/year in Year 1, compared to 9.57 cm/year for the somatropin cohort, with both groups having n=155. In Year 2, the somatrogon cohort had a height velocity of 7.70 cm/year versus 7.33 cm/year for the somatropin cohort, and in Year 3, the values were 7.15 cm/year for somatrogon and 6.56 cm/year for somatropin. Mean changes in height standard deviation scores were comparable, with somatrogon showing larger changes in Years 2-3.
Interpretation
The findings indicate that somatrogon may have comparable efficacy to daily somatropin in terms of height outcomes for pediatric patients with GHD. However, while the results are statistically significant, the clinical significance of the differences in height velocity may be small. Limitations include reliance on historical data and potential confounding factors not accounted for in the matching process, which may affect the robustness of the conclusions drawn.
Key findings
- Y1: 10.03 cm/year vs 9.57 cm/year for somatrogon vs somatropin, n=155 each cohort.
- Y2: 7.70 cm/year vs 7.33 cm/year for somatrogon vs somatropin, n=155 each cohort.
- Y3: 7.15 cm/year vs 6.56 cm/year for somatrogon vs somatropin, n=155 each cohort.
Limitations
- Matched cohort design may not control for all confounding variables.
- Relies on historical data for the KIGS cohort.
- Sample size of 155 in each cohort may limit generalizability.
- Follow-up duration of three years may not capture long-term effects.