BridgeBio Pharma has submitted a New Drug Application (NDA) to the US Food and Drug Administration for BBP-418, an oral therapy being developed for limb-girdle muscular dystrophy type 2I/R9 (LGMD2I/R9), following positive interim Phase 3 data from the FORTIFY study.

The submission includes interim results from the Phase 3 FORTIFY trial, which met all pre-specified primary and secondary endpoints at the 12-month analysis. The data showed statistically significant and clinically meaningful improvements in ambulation and pulmonary function, alongside a favourable safety profile, according to the company.

If approved, BBP-418 could become the first approved therapy for LGMD2I/R9, a rare, progressive neuromuscular disorder caused by mutations in the FKRP gene. It may also represent the first approved treatment for any form of limb-girdle muscular dystrophy.

LGMD2I/R9 is a monogenic, autosomal recessive disease that leads to progressive skeletal muscle weakness and can involve cardiac and respiratory decline over time. Disease severity varies depending on genotype, with some individuals experiencing early loss of mobility and others progressing to cardiomyopathy and respiratory impairment in adulthood.

BridgeBio said it is engaged in ongoing discussions with the FDA and anticipates a potential US launch in late 2026 or early 2027, subject to regulatory approval. The company is also exploring an expedited pathway in Europe.

Christine Siu, chief executive officer of BridgeBio Neuromuscular, said: “This NDA submission brings us one step closer to delivering the first approved therapy to individuals and families affected by LGMD2I/R9, a severe, progressive neuromuscular disease. This achievement reflects the strength of the data and our focus on addressing an area of significant unmet need.”

BBP-418 has previously received Orphan Drug, Fast Track and Rare Pediatric Disease designations from the FDA, as well as Orphan Drug designation from the European Medicines Agency. Based on its regulatory status, the application may be eligible for Priority Review, and could qualify the company for a Priority Review Voucher if approved.

BridgeBio also plans to initiate further clinical studies of BBP-418 in paediatric populations under 12 years of age, as well as in additional FKRP-related muscular dystrophy subtypes including LGMD2M/2U.

The FORTIFY study, a Phase 3 clinical trial, previously demonstrated positive interim results presented at the Muscular Dystrophy Association Clinical and Scientific Conference, supporting continued development of the oral therapy in genetically defined neuromuscular disease.

The NDA submission marks a key regulatory milestone for BridgeBio as it advances BBP-418 toward potential approval in a rare disease area with no currently approved disease-modifying therapies.