BridgeBio Pharma saw its stock rise 9% on Thursday following the release of topline Phase 3 results for oral infigratinib in achondroplasia. The company said the PROPEL 3 trial met its primary endpoint, reporting a superior change from baseline in annualized height velocity (AHV) versus placebo at Week 52.
Trial outcomes
According to the company, the mean treatment difference in AHV versus placebo was +2.10 cm/year, with a least squares mean of +1.74 cm/year. In a pre-specified exploratory analysis focusing on children younger than 8 years old - who represented more than half of trial participants - oral infigratinib produced the first statistically significant improvement in body proportionality compared with placebo, with a least squares mean treatment difference of -0.05.
Safety and tolerability
BridgeBio reported that oral infigratinib was well tolerated in the study population. There were no discontinuations or serious adverse events attributed to the study drug. The company recorded three cases of hyperphosphatemia, representing 4% of participants; these events were described as mild and transient, and none required dose reduction or discontinuation.
Regulatory and development plans
Following the PROPEL 3 results, BridgeBio said it intends to submit a New Drug Application (NDA) and a Marketing Authorization Application (MAA) in the second half of 2026. The company also noted that oral infigratinib currently holds Breakthrough Therapy Designation from the U.S. Food and Drug Administration, and that it is the only therapeutic program in development for achondroplasia to have received that designation.
On the basis of the Phase 3 results, BridgeBio plans to accelerate development of oral infigratinib for hypochondroplasia and is enrolling patients in the observational run-in portion of that Phase 3 trial.
About the condition
Achondroplasia is a genetic disorder caused by overactivity of FGFR3 and affects physical development and growth, most notably limb length and body proportions.
The company-provided results, regulatory timeline and expansion into hypochondroplasia shaped market reaction, with the stock responding to the clinical and programmatic news. Additional data and the regulatory review process will determine the next milestones for the program.