ESPE Abstracts

Background: CrescNet is a European pseudonymous paediatric registry of longitudinal measurements used to screen for growth disorders including achondroplasia (ACH). ACH is a rare genetic condition caused by a gain-of-function variant in the fibroblast growth factor receptor 3 (FGFR3) gene, resulting in severe disproportionate short stature and medical complications related to impaired endochondral bone growth. Vosoritide (C-type natriuretic peptide analogue) is indicated for treatment of genetically confirmed ACH, and since September 2023 is approved for children aged ≥4 months until epiphyseal closure. An ACH module was implemented within CrescNet in 2021, initially in Germany, to collect broader clinical parameters for individuals with ACH.

Methods: The CrescNet registry ACH module provides standardised data collection, including demographics, anthropometry, medical complications, growth-related treatments, developmental milestones, and quality-of-life questionnaires for all ACH individuals at participating centres. We describe participant demographics and treatment characteristics from January 2021 to November 2023, including vosoritide-treated participants.

Results: Overall, 319 individuals with ACH from 11 centres in 4 countries were enrolled in CrescNet. Most resided in Germany (n = 282; 88.4%); approximately half (n = 163; 51.1%) were male. Median age at enrolment was 6.1 years (quartile [Q]1–Q3: 2.4–11.6 years) and median (Q1–Q3) follow up time was 3.8 (0.8–9.5) years. In total, 2.8% of individuals underwent limb lengthening. Treatment with vosoritide post EMA approval was initiated by 112 participants (93.3%); mean (standard deviation [SD]) age at treatment start was 6.7 (3.9) years for males and 6.4 (3.5) years for females (range 0–15 years). Median (Q1–Q3) treatment duration was 1.7 (1.0–2.0) years. Among 54 participants (30 males, 24 females), treated with vosoritide for 12 months, mean (SD) height increase from baseline was 6.4 (1.96) cm, with Z-score improvement of 0.2 (0.54) (Z-score using German reference population). Furthermore, among 17 participants (12 males, 5 females) treated with vosoritide for 24 months, height increase from baseline was 11.0 (1.46) cm, with Z-score improvement of 0.6 (0.38).

Conclusion: The CrescNet ACH module was started in Germany, and expansion to additional European countries allows for broader representation of the ACH community. Data from 112 children treated with vosoritide indicate that outcomes of treatment in real-world setting appear consistent with clinical trial findings.