BridgeBio said on Thursday that another of its Phase 3 rare disease studies succeeded, its third in the last few months, setting up a filing with the FDA.
The latest win was in children with achondroplasia, the most common genetic form of dwarfism. In children between the ages of 3 and 17, BridgeBio’s oral drug infigratinib improved a measurement of their average annual growth rate by 1.74 centimeters a year, relative to a placebo (p<0.0001). Results were measured after all 114 patients had received the drug or placebo for at least one year.
Justin To, CEO of BridgeBio subsidiary QED Therapeutics, told
Endpoints News
that growth rate is expected to serve as the surrogate endpoint for an accelerated approval. BridgeBio plans to file in the second half of 2026.
For a confirmatory study, “we basically would be having the kids who are in this trial go out to what’s called ‘final adult height,’” To said. Some of the children will be followed for at least 10 years, and BridgeBio still needs to discuss with the FDA how much data are needed to convert to full approval.
Two other rare disease programs from BridgeBio also read out positive Phase 3 data last October. The company’s BBP-418 program
beat placebo
in limb-girdle muscular dystrophy type 2I/R9, and the oral drug encaleret
hit the primary endpoint
for a genetic thyroid disorder called autosomal dominant hypocalcemia type 1.
If all three drugs get approval, BridgeBio would be on track to launch the new products before the end of 2027. All three were developed in-house and would join the heart drug Attruby, approved in November 2024, on the market.
Achondroplasia affects about 15,000 to 20,000 people in the US, To said. While short stature is the most recognizable symptom, the condition can also cause neurological issues such as spinal compression, sleep apnea and frequent complications in the ear, nose and throat.
The FDA has only approved one drug for achondroplasia: BioMarin’s Voxzogo, an injectable drug that
hit the market
in 2021. But Ascendis Pharma is expecting to hear whether its own achondroplasia drug will be approved by the end of February. (Previously, the FDA
delayed
Ascendis’ decision date by three months.)
Voxzogo is meant to be taken once per day, while Ascendis’ drug, called TransCon CNP, is a once-weekly injection.
BridgeBio is hoping to set itself apart from potential competitors by touting infigratinib’s oral administration route. The drug comes in capsule form, but if children are too young to swallow it whole, the tablets inside the capsule can be crushed and sprinkled on top of food or in drinks.
Infigratinib is designed for children whose growth plates are still active, To said. The idea is to give patients the drug until they’re finished with puberty. BridgeBio could potentially explore moving infigratinib into adults with achondroplasia to treat some of the spinal compression issues.
Ultimately, BridgeBio believes it can capture at least 50% of the achondroplasia market, which To emphasized is made up of patients who want to take medication. Multiple patient advocate groups such as the Little People of America have campaigned against the need for dwarfism drugs, but To said infigratinib’s ability to help with complications makes it appealing for some with the condition.
“This is not meant to be a cosmetic drug. It’s about health,” To said.