BioMarin is focused on its CNP analog, Voxzogo, to write the next chapter of the company’s growth story, but changes to its clinical development plan are adding further uncertainty to the company’s calculations.
BioMarin will discontinue dosing and enrollment in its Phase 2 trial of Voxzogo, currently approved for achondroplasia, a form of dwarfism, in three potential indications: Turner syndrome, SHOX deficiency, and aggrecan (ACAN) deficiency.
The move follows reports of “several” slipped femoral epiphysis (SCFE) events, in which the femoral head slips out of place, in two investigator-initiated trials of the drug, BioMarin said in a March 16 securities filing (PDF).
BioMarin emphasized that no SCFE events were observed in its Phase 2 Voxzogo trial in the same indication, and no cases were observed in the more than 5,000 infants and children treated for achondroplasia.
The drug has no reported SCFEs, even in the achondroplasia trial in which BioMarin is targeting Voxzogo’s next potential expansion.
Not all of BioMarin’s mid-stage Voxzogo program has been hit, with the company saying its Phase 2 study of the drug in children with Noonan syndrome and children with idiopathic short stature (ISS) without ACAN deficiency will continue “as planned.”
BioMarin said it will implement new precautionary safety measures in its ongoing clinical trials, including additional imaging procedures to reduce potential risks to participating children.
Although the suspension of dosing and enrollment for patients with ACAN deficiency is likely to have a slight impact on its second study, BioMarin noted that participants without deficiency accounted for approximately 95% of participants enrolled in the ISS trial.
Voxzogo, a daily injection, was first approved by the FDA for the treatment of achondroplasia in November 2021 to promote linear growth in patients age 5 and older with open growth plates. Since then, the drug has been given the green light to treat children with achondroplasia of any age who have open growth plates.
In terms of indications targeted by BioMarin’s clinical pivot, Turner syndrome is a genetic disease affecting girls and women caused by partial or complete deletion of the X chromosome, resulting in short stature and premature ovarian failure. According to BioMarin, SHOX deficiency, or short stature homeobox-containing gene deficiency, is caused by alterations or deletions in the SHOX gene and is associated with “a wide range of short stature phenotypes, including Turner syndrome and Lehri-Weyl chondroosteogenesis imperfecta.”
Aggrecan deficiency is caused by mutations in the ACAN gene and can lead to short stature and often early-onset osteoarthritis and degenerative disc disease.
Back in 2024, when BioMarin CEO Alexander Hardy set a goal for the company to reach $4 billion in revenue by 2027, BioMarin noted that Voxzogo could be common in Noonan syndrome, Turner syndrome, and SHOX deficiency, reaching that goal by 2031.
Apart from the latest clinical move, BioMarin later withdrew its $4 billion target amid the growing threat of competition from Voxzogo.
Earlier this month, the FDA granted full clearance to Ascendis Pharma’s Uviwell to treat achondroplasia in children 2 years and older, who have open growth plates. Notably, unlike Voxzogo, which is administered once a day, Yuviwel, which is also an injection, only needs to be administered once a week.
At the time, Ascendis said it planned to bring Ubiwell to the U.S. market by the second quarter of this year.
Voxzogo achieved sales of $927 million for all of 2025, an increase of 26% compared to the previous year’s sales. BioMarin expects sales of the drug to rise from $975 million to just over $1 billion in 2026, according to the company’s latest earnings report.
The company’s stock price was down about 2% as of 11:30 a.m. ET on Monday, March 16th.
