BridgeBio performs well, Phase 3 data puts dwarfism drug on track for FDA filing
A drug developed by BridgeBio Pharma to target dwarfism increased children's growth rates in a pivotal clinical trial, achieving the study's primary goal and increasing the chances that a daily pill could become an alternative to chronic injections to treat the disease.
BridgeBio's drug infigratinib was tested in a placebo-controlled Phase 3 study that enrolled 113 children ages 3 to 18 with achondroplasia, the most common form of dwarfism. Preliminary data reported Thursday showed that daily doses of the study drug increased annualized height velocity by an average of 2.1 centimeters from baseline compared with placebo. Compared with placebo, the absolute change in height at one year averaged 1.74 cm.
Achondroplasia can also affect body proportions. BridgeBio reported that infigratinib met a key secondary objective, achieving a statistically significant improvement in the proportion of children younger than 8 years old compared with placebo.
Infigratinib was well tolerated, with no serious adverse events reported related to the study drug. and there were no discontinuations or dose reductions. There were three cases of hyperphosphatemia, an elevated level of phosphate in the blood. BridgeBio said the cases were considered mild and transient and did not require dose reduction or discontinuation of infigratinib. Based on the trial results, BridgeBio now plans to submit regulatory applications for the drug in the United States and Europe later this year.
Achondroplasia causes bone growth to slow down, especially in the long bones of the arms and legs. It is caused by a genetic mutation that causes overactivity of fibroblast growth factor receptor 3 (FGFR3), a protein that downregulates bone growth. Infigratinib is an oral small molecule designed to inhibit FGFR3.
BioMarin Pharmaceutical currently markets the only FDA-approved treatment for achondroplasia. The drug, Voxzogo, is a peptide analog that balances FGFR3. Since its approval in 2021, the drug has become BioMarin's best-selling product. For the first nine months of 2025, BioMarin reported Voxzogo revenue of $654 million, up 24% from the same period a year earlier. The company expects full-year revenue from the product to be between $900 million and $935 million.
Voxzogo requires daily injections, which can be challenging for some patients, especially children. Ascendis Pharma aims to ease the dosing burden with its peptide drug navepegritide, which is developed as a once-weekly injection. The drug is under review by the FDA, with a target date of February 28 for a regulatory decision.
By offering patients an oral option, BridgeBio will be able to differentiate itself from BioMarin and Ascendis drugs. Preliminary data on the drug also suggests it may provide better efficacy. While the drugs were not tested head-to-head, BridgeBio's drug achieved annualized gains in Phase 3 testing that exceeded the scores BioMarin and Ascendis' drugs showed in their respective pivotal studies.
Leerink Partners analyst Joseph Schwartz said in a research note that the Ascendis drug also showed improvements in body proportions, which key opinion leaders (KOLs) say may be a key point in choosing a treatment. He added that oral medications can be a disadvantage for younger children because they may not be able to swallow the pills, leaving a place on the market for injectables.
“While the overall picture of these infigratinib data is compelling, we still believe it remains to be seen how the dynamic between oral and injectable therapies will play out in achondroplasia, as we heard very different feedback from MEDACorp KOL discussions regarding patient/physician/parent preferences for different routes of administration,” Schwartz wrote.
Leerink expects infigratinib to win regulatory approval and expects peak sales of the drug to reach $1.5 billion.
BridgeBio is conducting additional clinical trials of infigratinib. An ongoing study in achondroplasia is evaluating the drug in infants and young children younger than 3 years of age. The company is also developing the drug to treat a less severe form of dwarfism called achondroplasia. BridgeBio is recruiting participants for an observational run-in period to select patients for a Phase 3 clinical trial in this indication.
Photo by Flickr user Sean MacEntee via Creative Commons license
