BioMarin reports new clinical and real-world data showing early treatment with VOXZOGO improves growth, body proportionality, and skeletal development in children with achondroplasia.
Written By: Marka Sheshi, PharmD
Reviewed By: Pharmacally Editorial Team
BioMarin Pharmaceutical Inc. reported new clinical and real-world data demonstrating the benefits of early treatment with VOXZOGO (vosoritide) in children with achondroplasia. The findings, to be presented at the 2026 American College of Medical Genetics and Genomics (ACMG) Annual Clinical Genetics Meeting in Baltimore, show that initiating therapy during infancy leads to sustained improvements in growth and body proportionality.
Greg Friberg, M.D., Executive Vice President and Chief Research & Development Officer at BioMarin, noted that the findings reinforce clinical guidance indicating that earlier initiation of VOXZOGO can maximize treatment benefits, including improvements in proportionality and overall health outcomes.
Data from ongoing clinical studies (NCT03583697) showed that children who began VOXZOGO before the age of two experienced durable, multi-year improvements in growth and skeletal proportionality compared with untreated children.
Body proportionality was evaluated using the upper-to-lower body segment ratio (ULBR). By year one, the least squares mean difference in ULBR versus untreated children was −0.33 (p=0.0005) in children who initiated treatment before six months of age and −0.10 (p=0.042) in those who started therapy before two years of age. These improvements increased over time, reaching −0.53 (p<0.0001) and −0.23 (p=0.0003), respectively, by year four (NCT02724228).
Early treatment was also associated with sustained gains in height and arm span while maintaining stable arm-to-height ratios, indicating improved skeletal development during early childhood. Significant improvements in body mass index (BMI) were also observed in treated children compared with untreated peers.
Among more than 20 children who initiated VOXZOGO between six months and two years of age, the average additional height gain after four years of treatment was 4.7 cm (p=0.0002). An improvement in height Z-score of 0.8 (p=0.0008) was also reported compared with untreated children, supporting sustained gains relative to expected growth patterns in achondroplasia.
Real-world evidence presented at the meeting further supported these findings. To date, more than 5,000 infants and children across over 50 countries have received VOXZOGO.
In Japan, children younger than two years treated with the therapy demonstrated strong adherence and robust growth gains, with a mean height increase of 9.91 cm at 12 months and 15.62 cm at 24 months.
Michael Hughes of Little People of America highlighted the growing importance of outcomes beyond height, noting that measures such as body proportionality and arm span help expand understanding of skeletal development in achondroplasia and support more informed discussions between families and healthcare providers.
Additional real-world data from France showed sustained benefits after 36 months of treatment, including a mean height gain of 16.7 cm and a 0.75 increase in height Z-score.
These findings were supported by interim observations from the ongoing Acorn Study, a multicenter post-authorization safety study in Europe designed to follow participants for up to 10 years.
Further evidence from the U.S.-based Virtual Study in Achondroplasia (VISTA) showed real-world effectiveness consistent with clinical trial outcomes, along with trends toward improvements in physical functioning.
VOXZOGO remains the only approved therapy for children with achondroplasia starting from birth, and the latest evidence continues to support the importance of early treatment to maximize improvements in growth and overall skeletal development.
References
BioMarin Presents New Data on the Positive Impact of Early Treatment With VOXZOGO® (vosoritide) on Proportionality and Arm Span in Children with Achondroplasia at the 2026 American College of Medical Genetics and Genomics (ACMG) Annual Clinical Genetics Meeting, 12 March 2026, BioMarin Pharmaceutical Inc. – BioMarin Presents New Data on the Positive Impact of Early Treatment With VOXZOGO® (vosoritide) on Proportionality and Arm Span in Children with Achondroplasia at the 2026 American College of Medical Genetics and Genomics (ACMG) Annual Clinical Genetics Meeting
A Clinical Trial to Evaluate the Safety and Efficacy of BMN 111 in Infants and Young Children with Achondroplasia, ClinicalTrials.gov ID NCT03583697, https://clinicaltrials.gov/study/NCT03583697
A Study to Evaluate Long-Term Safety, Tolerability, & Efficacy of BMN 111 in Children with Achondroplasia (ACH) (ACH), ClinicalTrials.gov ID NCT02724228, https://clinicaltrials.gov/study/NCT02724228
About the Writer
Marka Sheshi | Doctor of Pharmacy
Driven by a deep commitment to clinical excellence, research integrity, and impactful medical writing. With a strong foundation in pharmacotherapy and patient safety, specializes in transforming complex scientific evidence into authoritative, publication-ready content. Passionate about advancing healthcare through precise, evidence-based communication that informs practice, strengthens research visibility, and improves patient outcomes.