Dive Brief:
- BioMarin is looking to expand the use of its top-selling medicine, Voxzogo, with positive study results released Wednesday.
- In 2021, Voxzogo became the first drug approved to improve growth in children with achondroplasia, the most common form of dwarfism. The new results pertain to a related condition called hypochondroplasia that generally presents in less severe ways and might not be noticed until later in a child’s life.
- In the Phase 3 trial, researchers found participants given Voxzogo were growing faster than those who received a placebo. After a year, the Voxzogo patients also had significant increases in standing height and arm span, a key finding that could help children function better in daily tasks and retain more independence.
Dive Insight:
The fresh results come as BioMarin faces increased competition for Voxzogo, a daily shot the company says may top $1 billion in sales this year. Ascendis Pharma in February won Food and Drug Administration approval for a once-weekly injection to treat achondroplasia and BridgeBio that same month reported success in a late-stage study of an experimental oral alternative.
While the monopoly in achondroplasia is ending, the new study puts BioMarin well ahead of rivals in hypochondroplasia with a “relatively high efficacy bar,” Evercore ISI analyst Cory Kasimov wrote in a note to clients. He expects $600 million in peak sales for the condition.
In both achondroplasia and hypochondroplasia, a patient’s body doesn’t properly turn cartilage into bone, particularly in the arms and legs. People with these conditions typically have large heads, a sway in the lower back, bowed legs and limited motion in the elbows. In hypochondroplasia, effects are usually milder; a man with the condition could reach a height of between 4’6” and 5’5”, compared with an average height of 4’4” for a man with untreated achondroplasia.
As a result, hypochondroplasia can take longer to catch or remain undiagnosed in children. There may be a lack of “urgency to treat,” Raymond James analyst Christopher Raymond wrote in a note to clients. He expects Voxzogo revenue from hypochondroplasia will reach as much as $178 million in the U.S. within five years, as well as a “meaningful upside” in international markets.
Other analysts, however, argue it’s hard to estimate the potential in hypochondroplasia. “It remains somewhat unclear to us how big this market really is,” Stifel analyst Paul Matteis wrote. “At the very least this is a market that probably needs to be built, as specialists with whom we’ve spoken with in the past often see materially fewer [hypochondroplasia] patients vs. achondroplasia.”
BioMarin plans to submit a supplemental approval application to the FDA in the third quarter, asking the agency to clear Voxzogo for this added indication. The company currently has a conditional, “accelerated approval” for the drug in achondroplasia and has also asked the FDA for full clearance there.
The latest results came two days after BioMarin announced that one of its experimental medicines missed one of the two main goals of a Phase 3 study. The results clouded the future of that drug, BMN401, which is designed to treat a rare condition called ENPP1 deficiency.
