Savarirayan, RaviTofts, LouiseIrving, MelitaWilcox, William RBacino, Carlos AHoover-Fong, JulieFont, Rosendo UllotHarmatz, PaulRutsch, FrankBober, Michael BPolgreen, Lynda EGinebreda, IgnacioMohnike, KlausCharrow, JoelHoernschemeyer, DanielOzono, KeiichiAlanay, YaseminArundel, PaulKotani, YumikoYasui, NatsuoWhite, Klane KSaal, Howard MLeiva-Gea, AntonioLuna-González, FelipeMochizuki, HiroshiBasel, DonaldPorco, Dania MJayaram, KalaFisheleva, ElenaHuntsman-Labed, AliceDay, Jonathan R S2025-01-072025-01-072021-08-02https://hdl.handle.net/10668/27064Achondroplasia is caused by pathogenic variants in the fibroblast growth factor receptor 3 gene that lead to impaired endochondral ossification. Vosoritide, an analog of C-type natriuretic peptide, stimulates endochondral bone growth and is in development for the treatment of achondroplasia. This phase 3 extension study was conducted to document the efficacy and safety of continuous, daily vosoritide treatment in children with achondroplasia, and the two-year results are reported. After completing at least six months of a baseline observational growth study, and 52 weeks in a double-blind, placebo-controlled study, participants were eligible to continue treatment in an open-label extension study, where all participants received vosoritide at a dose of 15.0 μg/kg/day. In children randomized to vosoritide, annualized growth velocity increased from 4.26 cm/year at baseline to 5.39 cm/year at 52 weeks and 5.52 cm/year at week 104. In children who crossed over from placebo to vosoritide in the extension study, annualized growth velocity increased from 3.81 cm/year at week 52 to 5.43 cm/year at week 104. No new adverse effects of vosoritide were detected. Vosoritide treatment has safe and persistent growth-promoting effects in children with achondroplasia treated daily for two years.enAttribution 4.0 Internationalhttp://creativecommons.org/licenses/by/4.0/AchondroplasiaChildDouble-Blind MethodHumansNatriuretic Peptide, C-TypeTreatment Outcomeresearch article34341520open access10.1038/s41436-021-01287-71530-0366PMC8327889http://www.gimjournal.org/article/S1098360021054393/pdfhttps://pmc.ncbi.nlm.nih.gov/articles/PMC8327889/pdf