Vosoritide safe, effective for children with achondroplasia

Daily injections of vosoritide, a C-type natriuretic peptide analog, improved annualized growth velocity over 6 months in children with achondroplasia, the most common form of dwarfism, according to recent study findings presented at The American Society for Bone and Mineral Research Annual Meeting.

In the initial 6-month data from a phase 2, open-label, dose escalation study, researchers also noted no changes in body proportionality after 6 months of vosoritide therapy.

Melita Irving, BSc, MBBS MRCPCH, a clinical geneticist with Guys’ and St. Thomas’ NHS Foundation Trust in London, U.K., and colleagues analyzed data from 26 children with achondroplasia who completed at least 6 months of pretreatment growth assessment (mean age, 8 years; 14 girls). The children were assigned to one of three dose cohorts for 6 months: 2.5 µg/kg daily (n = 8); 7.5 µg/kg daily (n = 8) or 15 µg/kg daily (n = 10). Researchers measured changes in annualized growth velocity, absolute growth and body proportions.

Following 6 months of daily vosoritide therapy, mean annualized growth velocity decreased from 3.8 cm per year to 3.4 cm per year in the lowest dose cohort, however, annualized growth velocity increased from 2.9 cm per year to 4.2 cm per year in the 7.5 µg/kg daily cohort and from 4 cm per year to 6.1 cm per year in the 15 µg/kg daily cohort.

“A mean increase of 2 cm per year, which represents a 50% increase from the mean baseline annualized growth velocity, was observed in the 15 µg/kg daily dose cohort,” the researchers wrote.

Researchers observed no changes in body proportion over the study period.

The drug was well tolerated across all dose cohorts; adverse events included injection site irritation, asymptomatic hypertension and headache. There were no serious adverse events; no adverse events led to discontinuation of the drug.

“By developing a therapy that addresses the root cause of achondroplasia, we hope to address the associated complications, such as disproportionate bone growth,” Hank Fuchs, MD, executive vice president and chief medical officer at BioMarin, said in a press release announcing the initial results. “We are very encouraged with this initial data, and we look forward to working with health authorities and the patient community to advance vosoritide to the next stage of clinical development.”– by Regina Schaffer

Reference:

Irving M, et al. LB-1154. Presented at: The American Society for Bone and Mineral Research Annual Meeting; Oct. 9-12, 2015; Seattle.

Disclosure: This study received funding from BioMarin Pharmaceutical Inc.