BridgeBio Dwarfism Drug Outperforms BioMarin's Voxzogo in Increasing Children's Height

BridgeBio Pharma has announced promising developments concerning the daily oral FGFR3 inhibitor infigratinib, particularly for children with achondroplasia, a common form of dwarfism. This progress comes after the FDA withdrew accelerated approval for infigratinib in oncology due to enrollment difficulties for a required confirmatory trial initiated by BridgeBio’s former partner, Helsinn.

Despite setbacks in oncology, BridgeBio has continued to explore infigratinib's potential in treating dwarfism, yielding encouraging results. The company recently shared 12- and 18-month data from the midphase PROPEL 2 trial, building on earlier six-month findings that suggest the drug may outperform BioMarin’s approved dwarfism therapy, Voxzogo.

Children treated with infigratinib showed a mean annualized height velocity (AHV) increase of 2.51 cm/year at 12 months and 2.50 cm/year at 18 months. In comparison, the FDA approved Voxzogo based on a trial that demonstrated a 1.40 cm/year increase in AHV over 12 months. Additionally, infigratinib improved the upper to lower body ratio in children, decreasing from 2.02 at baseline to 1.88 after 18 months. This 0.14 improvement surpasses the changes reported by BioMarin over two years.

Dr. Ravi Savarirayan from the Murdoch Children’s Research Institute highlighted the significance of these body ratio changes, suggesting that infigratinib could enhance functionality and growth for individuals with achondroplasia. However, it's important to note that the AHV increase was higher at the six-month mark, at 3.38 cm/year, indicating some variability over time.

No treatment-related adverse events were reported, providing further encouragement for BridgeBio to advance the drug’s development. The company is currently conducting a phase 3 study in achondroplasia, with enrollment expected to be completed by the end of the year. Additionally, BridgeBio is planning to initiate a phase 3 trial for hypochondroplasia, another form of short-limbed dwarfism.

Following discussions with regulatory authorities, BridgeBio has launched a small, open-label phase 2 trial in hypochondroplasia. This study will evaluate infigratinib at the most promising dose identified in achondroplasia trials. The aim is to progress to a placebo-controlled phase 3 trial, positioning infigratinib as a potential new treatment for hypochondroplasia.

Meanwhile, BioMarin, whose product Voxzogo saw a 74% revenue increase in the first quarter, reaching $153 million, faces growing competition in the achondroplasia market. Companies like Ascendis Pharma and Sanofi are also developing treatments for this condition.

In summary, BridgeBio Pharma's continued investment in developing infigratinib for dwarfism conditions, despite challenges in its oncology applications, highlights its potential to surpass existing treatments like Voxzogo. With promising midphase trial results and ongoing phase 3 studies, BridgeBio is poised to make significant strides in providing new therapeutic options for both achondroplasia and hypochondroplasia.