BridgeBio’s Oral Infigratinib Achieves Highly Significant Growth in Achondroplasia in Phase 3 PROPEL 3 Trial

BridgeBio’s Oral Infigratinib Achieves Highly Significant Growth in Achondroplasia in Phase 3 PROPEL 3 Trial

On June 29, 2026, BridgeBio Pharma, Inc. announced the publication of robust results from its Phase 3 PROPEL 3 clinical trial of oral infigratinib in children living with achondroplasia in the New England Journal of Medicine (NEJM). The trial met its primary and all key secondary endpoints with high statistical significance, positioning the once-daily oral pill as a highly competitive alternative to BioMarin's approved daily-injection therapy¹ Voxzogo (vosoritide).²

Achondroplasia is the most common cause of disproportionate short stature, driven by an activating variant in the FGFR3 gene. Infigratinib is an investigational oral small-molecule FGFR3 inhibitor designed to target the condition at its source.

Key findings from the 52-week, randomized, double-blind, placebo-controlled Phase 3 PROPEL 3 trial include:

• Primary Endpoint Met: Children treated with oral infigratinib achieved a least-squares (LS) mean annualized height velocity (AHV) difference of +1.74 cm/year compared to placebo ($p < 0.0001$). The observed mean AHV difference was +2.10 cm/year ($p < 0.0001$).
• Height Z-score Increase: Treated children showed an LS mean increase in height Z-score of +0.41 SD at Week 52 ($p < 0.0001$).
• Improved Body Proportionality: The trial demonstrated a statistically significant improvement in body proportionality, with an LS mean treatment difference of -0.05 in children aged 3 to 8 years ($p < 0.05$).
• Arm Span Z-score Increase: Treated children achieved an LS mean arm span Z-score improvement of +0.37 SD vs. placebo ($p < 0.0001$).
• Favorable Safety Profile: Infigratinib was well-tolerated with no study-drug-related serious adverse events (SAEs) or discontinuations. Cases of hyperphosphatemia (a known class effect) occurred in only 4% of participants and were mild, transient, and asymptomatic, requiring no dose modifications.

Based on these positive results, BridgeBio plans to submit a New Drug Application (NDA) to the FDA in Q3 2026 and a Marketing Authorization Application (MAA) to the EMA in H2 2026. With multiple FDA designations—including Breakthrough Therapy, Fast Track, Orphan Drug, and Rare Pediatric Disease—infigratinib is positioned for a potential U.S. commercial launch in early-to-mid 2027.

Verbatim Quotes

• Stock Titan Summary: "The trial met primary and key secondary endpoints, showed improved height, body proportionality and arm span, and supported planned FDA/EMA submissions starting Q3 2026."
• BridgeBio Press Release: "In PROPEL 3, infigratinib improved arm span Z-score by +0.37 SD versus placebo at 52 weeks. According to BridgeBio, this represents the first statistically [significant arm span improvement reported in achondroplasia]."