BioMarin Pharmaceutical has reported data from the Phase II clinical trial of Voxzogo (vosoritide) for injection in infants and children aged under five years. 

A C-type natriuretic peptide (CNP) analogue, Voxzogo is claimed to boost endochondral bone growth by acting as a positive regulator of the signalling pathway downstream of FGFR3.

The randomised, double-blind, placebo-controlled, 52-week trial enrolled 75 infants and young children with achondroplasia under the age of five years. 

It had three age-based cohorts and was followed by an open-label extension trial where all subjects received active treatment. 

Assessing safety, tolerability and the impact of Voxzogo on growth are the trial’s objectives. 

According to findings from the overall population of all randomised and sentinel participants, Voxzogo demonstrated an improvement in height Z-score versus placebo at 52 weeks. 

Height Z-score measures height adjusted for age and sex with respect to the average stature population and is reported as a standard deviation (SD).

Voxzogo improved height Z-score by 0.30 SD and annualised growth velocity (AGV) by 0.92cm/year versus placebo. 

This improvement in height Z-score was similar to those seen earlier following treatment for a year of treatment in children aged over five years. 

A trend toward higher height Z-score was seen in the randomised population, exclusive of sentinel participants, and in the individual age subgroups.

Voxzogo’s safety profile was in line with those reported in older participants in the Phase III Voxzogo 301 study trial.

BioMarin Worldwide Research and Development president Hank Fuchs said: “We are pleased by these 52-week analysis results showing positive changes with Voxzogo compared to placebo in height Z-score and AGV. 

“We look forward to discussing the next steps regarding our efforts to expand access to Voxzogo treatment for this younger age group.”

In the second half of this year, the company anticipates meeting regulatory agencies to hold talks on the next steps to extend access to Voxzogo for treating achondroplasia in younger children.