A Phase III global clinical trial by the Murdoch Children’s Research Institute (MCRI) has found that a new drug, known as vosoritide, is able to increase bone growth in children with achondroplasia, the most common type of dwarfism.
A genetic bone disorder, achondroplasia, is known to affect around 250,000 people globally or approximately 1 in every 25,000 children. The condition is caused by overactivity of the FGFR3 protein, which reduces bone growth in children’s limbs, spine, and the base of the skull. Rather than growing 6-7 cm per year, children with the condition grow an average of 4cm per year. Current treatments for the condition, which include surgery, only address symptoms of the disorder.
Vosoritide, on the other hand, directly targets the molecular cause of the disease. It works by blocking the protein’s activity, ultimately returning growth rates to normal. While previous trials by MCRI showed that the drug is safe in young people with dwarfism, the new trial shows that it is also able to increase bone growth over one year with daily injections.
For the randomized, placebo-controlled trial, researchers enrolled 121 children aged between 5 and 18 in 24 hospitals across seven countries. All in all, the researchers found that the the 60 children who received daily injections of vosoritide grew an average of 1.57 cm more than children who received the placebo- bringing their growth rates more or less in line with peers who do not have the disorder.
The researchers did note, however, that the drug did not significantly improve the proportions between their upper and lower bodies. Nevertheless, the children will be followed until they reach their final adult height to see whether the drug’s effects are long-lasting and whether they have a growth spurt during puberty- something that is unusual among children with achondroplasia.
Nevertheless, BioMarin Pharmaceutical, the manufacturer of the drug and funder of the trial, has applied to the US Food and Drug Administration to license vosoritide as a treatment for achondroplasia. The company also applied to the European Medicines Agency, which has since approved their application.