Endocrine Abstracts

JOINT2273

Introduction: Achondroplasia is the most common skeletal dysplasia with severe short stature. It is characterized by gain-of-function variants in the FGFR3 gene. In Brazil, vosoritide was approved in 2021 for ACH children ages 2 years and older, then in 2023 it was approved for children ages 6 months and older.

Objective: to assess the real-world response of children with achondroplasia to Vosoritide.

Methods: Thirty-two children with genetic confirmed achondroplasia initiated treatment with Vosoritide. Height and weight were measured. Changes in height SDS based on WHO growth curves (WHO) or based on achondroplasia specific growth curves (ACH) were assessed after 6 months (n = 21) and after 1 year (n = 14) of treatment. Adverse events were assessed in all 32 children.

Results: The mean age at start of treatment was 6.1 years. Data for the whole group: Twelve females completed 6 months of treatment and 9 completed 12 months. Even though there was an increment in height SDS after 6 or 12 months, this change was not statistically different. On the other hand, despite having fewer male individuals (9 completed 6 months and 6 completed 12 months) there was a significant difference in height SDS. Safety: Eight patients presented hypertricosis (7 females) that was noticed after a mean duration of treatment of 4.37 ± 1.99 months and a range of 3 and 8 months. Three patients reported local pain at injection site.

Discussion: There is an overall increment in height of children with Achondroplasia in response to the treatment with Vosoritide. Changes in height SDS can be better observed using specific standards for individuals with achondroplasia. The response was better in males. One possible explanation is that some children do not respond robustly to the treatment and in our cohort, we had two, both females.

Conclusion: Treatment was well tolerated. The difference in SDS based on Achondroplasia standards is more significant than based on WHO standards.