BridgeBio Reports Positive Phase 3 Results for Oral Achondroplasia Therapy

Rare Daily Staff

BridgeBio Pharma said its experimental oral drug, infigratinib, helped children with achondroplasia grow faster and showed the first statistically significant gains in body proportionality reported in a randomized trial for the condition.

Based on the results, the company said it will meet with regulators to discuss plans for submitting applications to market infigratinib in the second half of 2026 in the United States and Europe.

Achondroplasia is the most common cause of disproportionate short stature. The condition affects overall health and quality of life, leading to medical complications such as obstructive sleep apnea, middle ear dysfunction, kyphosis, and spinal stenosis. It is uniformly caused by an activating variant in the FGFR3 gene.

Infigratinib is an oral small molecule designed to inhibit FGFR3 signaling and target achondroplasia and hypochondroplasia at their source. Currently, the only approved drug for children with achondroplasia and open growth plates is BioMarin’s Voxzogo, a once-daily injectable therapy that promotes bone growth.

In the global Phase 3 PROPEL study, which followed children ages 3 to under 18 for one year, infigratinib met its main goal by increasing annualized height velocity compared with placebo. The study found an average improvement of 2.10 centimeters per year over placebo at Week 52, a result the company said was highly statistically significant.

BridgeBio reported that children receiving infigratinib reached an average annual growth rate of 5.96 centimeters, compared with 4.22 centimeters for those on placebo. The company described this as the highest mean annualized height velocity yet seen in a randomized achondroplasia trial.

The drug also improved height Z-scores—a standardized measure comparing growth with an achondroplasia reference population—with a treatment difference of 0.32 standard deviations versus placebo and a 0.41 standard deviation gain in the treatment arm alone, both statistically significant.

In a prespecified exploratory analysis of the key secondary endpoint, oral infigratinib also achieved the first statistically significant improvement in body proportionality compared with placebo in achondroplasia.

The safety profile in PROPEL 3 was described as favorable, with no treatment-related serious adverse events and no discontinuations due to the study drug over the 52-week period.

“There remains a significant unmet need for therapeutic options that are effective, practical, and less invasive for children living with achondroplasia,” said Daniela Rogoff, chief medical officer for skeletal dysplasia at BridgeBio. “The PROPEL 3 data support the potential of an oral medicine directly targeting FGFR3 overactivity to address important clinical needs, while fitting into daily life for families who are seeking a noninjectable option.”