BridgeBio published full Phase 3 PROPEL 3 results for oral infigratinib in The New England Journal of Medicine, adding new arm span data while confirming significant improvements in growth, body proportionality, and a favorable safety profile in children with achondroplasia ahead of planned FDA and EMA submissions.
Written By: Disha Jadhav, BPharm
Reviewed By: Pharmacally Editorial Team
BridgeBio Pharma has published the full Phase 3 PROPEL 3 trial results of oral infigratinib in The New England Journal of Medicine (NEJM), providing peer-reviewed validation of the therapy’s efficacy and safety in children with achondroplasia. The data were also presented during a late-breaking oral session at the 12th International Conference on Children’s Bone Health (ICCBH) 2026, where investigators reported additional evidence showing significant improvements in arm span compared with placebo.
The publication builds on topline Phase 3 results released in February 2026 and introduces new analyses that further support oral infigratinib as a potential first-in-class oral treatment for achondroplasia. BridgeBio plans to submit a New Drug Application (NDA) to the U.S. Food and Drug Administration (FDA) in the third quarter of 2026, followed by a Marketing Authorization Application (MAA) to the European Medicines Agency (EMA) in the second half of the year.
Oral FGFR3 inhibition for achondroplasia
Achondroplasia is the most common genetic cause of disproportionate short stature and results from activating mutations in the fibroblast growth factor receptor 3 (FGFR3) gene, which suppress normal bone growth. Current treatment options remain limited, and no oral therapy has been approved for the condition.
Infigratinib is an oral, selective FGFR1-3 tyrosine kinase inhibitor administered at low doses to preferentially inhibit overactive FGFR3 signaling, the underlying molecular driver of achondroplasia.
Phase 3 PROPEL 3 confirms efficacy with additional peer-reviewed findings
The global Phase 3 PROPEL 3 study (NCT06164951) evaluated oral infigratinib in children with achondroplasia and met its primary and key secondary efficacy endpoints at 52 weeks.
As previously reported, treatment significantly improved annualized height velocity, achieving a least squares (LS) mean treatment difference of +1.74 cm/year versus placebo (p<0.0001), while the observed mean improvement reached +2.10 cm/year, the largest increase reported in a Phase 3 achondroplasia study. Children receiving infigratinib also showed significant improvements in height Z-score, with an LS mean increase of +0.41 standard deviations from baseline (p<0.0001).
The NEJM publication and ICCBH presentation also included new data showing a statistically significant improvement in arm span Z-score, with an LS mean treatment difference of +0.37 standard deviations versus placebo (p<0.0001). According to BridgeBio, this represents the first statistically significant placebo-controlled improvement in arm span reported in an achondroplasia clinical trial.
The study further confirmed previously reported improvements in body proportionality among children aged 3 to 8 years, with an LS mean treatment difference of −0.05 compared with placebo (p<0.05), making oral infigratinib the first therapy to demonstrate statistically significant proportionality improvements in a Phase 3 achondroplasia study.
Safety findings remained consistent with the February topline analysis. No participants discontinued treatment because of study drug-related adverse events, and investigators reported no treatment-related serious adverse events. Mild, transient hyperphosphatemia occurred in three patients (4%) and resolved without dose reduction or treatment discontinuation. No adverse events associated with FGFR1 or FGFR2 inhibition, including retinal or corneal toxicity, were observed.
Publication strengthens evidence ahead of regulatory review
Lead investigator Ravi Savarirayan, M.D., Ph.D., said publication in NEJM marks an important milestone for skeletal dysplasia research and reinforces oral infigratinib’s potential to become a mechanistically distinct treatment that directly targets FGFR3. He noted that the therapy demonstrated the highest annualized growth velocity and the greatest improvement in body proportionality reported among current Phase 3 studies in achondroplasia.
Alongside the pivotal trial results, investigators presented findings from the observational PROPEL study showing reduced health-related quality of life among children with achondroplasia, particularly in physical functioning. Additional qualitative research also supported the use of patient-reported outcome measures in children with hypochondroplasia and their caregivers for future clinical studies.
BridgeBio expects to submit its NDA for achondroplasia in the third quarter of 2026 and its EMA marketing application later this year. If approved, oral infigratinib could become the first oral therapy available for children living with achondroplasia, with a U.S. launch anticipated in early to mid-2027.
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About the Writer
Disha Sanjay Jadhao (LinkedIn) is a pharmacy graduate and healthcare writer with a strong interest in clinical documentation and simplifying healthcare information for better reader understanding. She is enthusiastic, adaptable, and eager to take on new challenges while contributing to clear, accurate, and engaging medical and pharmaceutical content.