The US Food and Drug Administration (FDA) has announced its approval of Voxzogo (vosoritide), an injectable drug intended to boost growth in children five and older and with open epiphyses (growth plates), with the potential to grow. Achondroplasia is the most common form of dwarfism.
Theresa Keho, director of the Division of General Endocrinology in the Center for Drug Evaluation and Research (CDER), said the approval offers hope to children with achondroplasia.
“Today’s approval fulfills an unmet medical need for more than 10,000 children in the United States and underscores the FDA’s commitment to help make new therapies available for rare diseases,” Keho said. “With this action, children with short stature due to achondroplasia have a treatment option that targets the underlying cause of their short stature.”
Achondroplasia is a genetic condition that causes severely short stature and disproportionate growth. The average height of a grown adult with achondroplasia is approximately four feet.
"Voxzogo is a medical first that is rooted in BioMarin's focus on molecular genetics and targets the underlying cause of the condition; more than a decade of scientific research underpins the medical advance that Voxzogo represents,” commented Jean-Jacques Bienaimé, CEO and hair of BioMarin. “We thank the FDA for recognizing its value as the first therapeutic treatment option for children with achondroplasia; we extend our gratitude to the community, clinical investigators, and the children and their families, who participated and continue to participate in our comprehensive clinical research program as we continue to investigate the full potential of vosoritide."
People with achondroplasia possess a genetic mutation that causes a growth regulation gene, called fibroblast growth factor receptor 3, to be overly active; this characteristic prevents normal bone growth. Voxzogo reportedly works by binding to a specific receptor (natriuretic peptide receptor-B) that reduces the growth regulation gene’s activity and stimulates bone growth.
"Achondroplasia is a lifelong genetic condition resulting from the disordered skeletal architecture caused by impaired endochondral bone growth throughout childhood," said Lynda Polgreen, an investigator at the Lundquist Institute at Harbor-UCLA and associate professor at David Geffen School of Medicine at UCLA. "This approval is an important milestone representing the first time that physicians will be able to offer a therapy targeted at the root cause of the condition for families of children with achondroplasia aged five and older."
According to the FDA, Voxzogo’s safety and efficacy in improving growth were evaluated in a year-long, double-blind, placebo-controlled, Phase III study in participants five years and older with achondroplasia who have open epiphyses. In the study, 121 participants were randomly assigned to receive either Voxzogo injections under the skin or a placebo.
Researchers measured the participants’ annualized growth velocity, or rate of height growth, at the end of the year. Participants who received Voxzogo grew an average of 1.57 centimeters (0.62 inches) taller compared to the patients who received a placebo.
The most common side effects of Voxzogo include injection site reactions, vomiting, and decreased blood pressure. Voxzogo’s labeling also lists decreased blood pressure as a warning and precaution, which means it is a potentially serious side effect.
The FDA approved Voxzogo under the accelerated approval pathway, which allows for earlier approval of drugs that treat serious conditions and fill an unmet medical need, based on a surrogate or intermediate clinical endpoint. A condition of this accelerated approval is a post-marketing study that will assess final adult height; this application also received priority review designation.