BridgeBio Stands Tall as Phase 3 Data Put Dwarfism Drug on Track for FDA Filing Leave a comment

A BridgeBio Pharma drug developed for dwarfism increased children’s growth rates in a pivotal clinical trial, meeting the study’s main goal and boosting the daily pill’s chances to offer an alternative to chronic injections used to treat the condition.

The BridgeBio drug, infigratinib, was tested in a placebo-controlled Phase 3 study that enrolled 113 children age 3 to 18 who have achondroplasia, the most common form of dwarfism. Preliminary data reported Thursday show that daily doses of the study drug led to an average 2.1 cm increase in annualized height velocity from baseline, measured at one year and compared to placebo. The absolute change in height was an average 1.74 cm compared to placebo at one year.

Achondroplasia can also affect body proportionality. BridgeBio reported infigratinib met a key secondary goal achieving statistically significant improvement in proportionality compared to placebo in children younger than 8 years old.

Infigratinib was well tolerated with no reports of serious adverse events related to the study drug. and no discontinuations or dose reductions. There were three cases of hyperphosphatemia, which is elevated levels of phosphate in the blood. BridgeBio said these cases were considered mild and transient, and none required dose reduction or discontinuation of infigratinib. Based on the trial results, BridgeBio is now planning regulatory submissions for the drug in the U.S. and Europe in the second half of this year.

Achondroplasia leads to slowing of bone growth, particularly in the long bones of the arms and legs. It’s caused by a genetic mutation that leads to excessive activity 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 therapy for achondroplasia. This drug, Voxzogo, is an analog of a peptide that counterbalances FGFR3. Since its approval in 2021, the drug has grown to become BioMarin’s top-selling product. In the first nine months of 2025, BioMarin reported $654 million in Voxzogo revenue, a 24% increase compared to the same period in the prior year. For the full year, the company projected the product would account for $900 million to $935 million in revenue.

Voxzogo requires daily injections, which can be challenging for some patients, particularly children. Ascendis Pharma aims to ease the dosing burden with its peptide drug, navepegritide, developed as a once-weekly injection. This drug is under FDA review with a Feb. 28 target date for a regulatory decision.

BridgeBio would be able to stand apart from the BioMarin and Ascendis drugs by bringing patients an oral option. The pill’s preliminary data also suggest it could offer better efficacy. While these drugs were not tested head to head, the annualized height velocity achieved by BridgeBio’s drug in Phase 3 testing tops the marks that the 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 improvement in body proportionality, which key opinion leaders (KOLs) say could be a key point for selecting a therapy. He added that an oral drug can be a disadvantage for young children who may be unable to swallow pills, leaving a place in the market for injectables.

“While the overall picture of these infigratinib data are compelling we still think it remains to be seen how the dynamic between oral and injectable therapies plays out in achondroplasia as we have heard highly varying feedback from our MEDACorp KOL discussions about patient/physician/parent preference for differing routes of administration,” Schwartz wrote.

Leerink expects regulatory approvals for infigratinib and projects the drug will reach $1.5 billion in peak sales.

BridgeBio is conducting additional clinical trials for infigratinib. An ongoing achondroplasia study is evaluating the drug in infants and toddlers younger than age 3. The company is also developing this drug for a less severe form of dwarfism called hypochondroplasia. BridgeBio is enrolling participants in the observational run-in period to select patients for a Phase 3 clinical trial in this indication.

Photo by Flickr user Sean MacEntee via a Creative Commons license