Achondroplasia win propels Bridgebio

Cut the data any which way, and results from cohort 5 of the Propel2 trial of Bridgebio’s infigratinib in achondroplasia are impressive. The project appears to be promoting substantially faster growth in these short stature children than Biomarin’s Voxzogo, with remarkably clean safety; ahead of the data analysts said a similar annualised height velocity to Voxzogo would be a win. Throw in infigratinib’s oral dosing versus Voxzogo’s subcutaneous injection and little wonder that Bridgebio stock soared as much as 73% today. SVB Securities described the data as setting “a new high water mark” in achondroplasia. True, these new phase 2 results are in only 10 patients, making direct comparisons with Voxzogo’s phase 3, represented in the “existing comparison” column below, full of caveats. Durability and safety need to be proven in a pivotal study, for which Bridgebio is already preparing. Assuming a year to enrol and a year to collect data, a filing in 2026 is probably the best-case scenario. That gives Biomarin plenty of time to make the most of Voxzogo, which sold $169m last year after a strong launch in late 2021. However, with Biomarin shares trading 5% lower, investors apparently believe the infigratinib threat is real.