BridgeBio Reports Promising Phase II Results for Dwarfism Treatment

BridgeBio announced promising Phase II results for its drug candidate infigratinib, aimed at treating children with achondroplasia, the most prevalent form of dwarfism. Infigratinib, an orally administered small molecule that inhibits FGFR3 signaling, addresses the disease at its root. The Phase II PROPEL 2 trial revealed significant findings, including a statistically significant mean increase in annualized height velocity of +2.51 cm/year from the baseline at 12 months, and +2.50 cm/year at 18 months, with a p-value of 0.0015.

The trial also demonstrated that infigratinib improved body proportionality, reducing it from 2.02 at baseline to 1.88 after 18 months, which achieved a p-value of 0.001. Moreover, the drug was well tolerated, with no treatment-related adverse events reported.

Ravi Savarirayan, the global lead investigator for the PROPEL 2 trial, highlighted the significance of these results, indicating that infigratinib continues to show increased growth velocity and improvements in body proportionality among children with achondroplasia. According to Savarirayan, this suggests that the drug has the potential to not only enhance growth but also improve functionality for individuals living with achondroplasia.

BridgeBio's infigratinib will face competition, particularly from BioMarin’s Voxzogo, which received FDA approval last year. However, some experts believe infigratinib may have certain advantages. According to analysts from Bank of Montreal Capital Markets, infigratinib is likely to offer improved efficacy compared to Voxzogo. They noted that infigratinib achieved better statistical significance for body proportionality and exhibited a clean safety profile compared to BioMarin’s drug. The analysts forecast that infigratinib could achieve peak sales of around $1.4 billion and potentially see about 50% of Voxzogo patients switching over.

BridgeBio plans to proceed with a Phase III trial for achondroplasia, aiming to complete enrollment by the end of the year. The company also seeks to extend the development of infigratinib to treat hypochondroplasia, a form of short-limbed dwarfism. BridgeBio has received positive feedback from both the FDA and EMA to support a Phase II study in this indication.

Daniela Rogoff, chief medical officer for skeletal dysplasias at BridgeBio, expressed enthusiasm for the continued evaluation of infigratinib in other FGFR-related skeletal dysplasias and genetic conditions. Rogoff pointed out that the initiation of an observational study in hypochondroplasia and the alignment with FDA and EMA on interventional studies underscore the potential of infigratinib as a treatment option for children with hypochondroplasia.

However, infigratinib has faced regulatory challenges in the past. In May 2024, its accelerated approval for treating metastatic cholangiocarcinoma was withdrawn upon the sponsor's request due to difficulties in recruiting and enrolling participants for a confirmatory trial.