BridgeBio Pharma Hits Enrollment Target and Gets FDA Rare Pediatric Disease Designation for LGMD2I/R9 Treatment

BridgeBio Pharma, Inc., a biopharmaceutical company specialized in genetic diseases, has achieved its interim enrollment target for the Phase 3 FORTIFY study of BBP-418 in individuals with LGMD2I/R9. The company expects to release top-line interim data from this study in 2025.

The FORTIFY study, a randomized, double-blind, placebo-controlled Phase 3 trial, aims to evaluate the safety and efficacy of BBP-418, an investigational oral therapy designed to treat LGMD2I/R9. The study includes a planned interim analysis at 12 months, focusing on glycosylated alpha-dystroglycan (αDG) as a surrogate endpoint. This analysis is intended to support a bid for Accelerated Approval. The primary endpoint, to be assessed at 36 months, is the North Star Assessment (NSAD) for limb-girdle type muscular dystrophies, aimed at providing confirmatory clinical data. BridgeBio continues to enroll participants in the U.S., UK, Europe, and Australia.

The company has had multiple discussions with the FDA in 2024 regarding the validated glycosylated αDG bioassay and interim analysis plans, reinforcing their belief in the potential for Accelerated Approval for BBP-418. The FDA has indicated that the company’s approach to measuring glycosylated αDG levels via a novel, validated muscle tissue-based bioassay is reasonable. A peer-reviewed manuscript detailing the novel, multiplexed, fluorescence-based Western Blot assay was recently published in the Journal of Muscle Research and Cell Motility.

Douglas Sproule, M.D., M.Sc., chief medical officer of ML Bio Solutions, a BridgeBio affiliate, emphasized the severe impact of reduced glycosylated αDG in LGMD2I/R9. This serious and progressively debilitating disease weakens muscles, often leading to dependency on caregivers and compromising cardiac and respiratory function. Sproule expressed hope for continued progress in enrolling participants in the Phase 3 FORTIFY study and ongoing collaboration with the FDA to expedite the development of this potential new therapeutic option for individuals with LGMD2I/R9.

Additionally, the FDA has granted Rare Pediatric Disease Designation (RPDD) for BBP-418 in the treatment of LGMD2I/R9. This designation acknowledges the rarity and seriousness of the disease, which primarily affects children. If BBP-418 is approved, BridgeBio may qualify for a Priority Review Voucher. This voucher could be applied to another therapy in the company’s pipeline for a shorter review timeline or could be sold to another company seeking priority review for one of its applications.

LGMD2I/R9 is a monogenic autosomal recessive disease caused by partial loss of function mutations in the FKRP gene, which impairs glycosylation of alpha-dystroglycan (αDG), a protein that stabilizes muscle cells. The disease typically presents as skeletal myopathy affecting the lower and upper limbs, followed by respiratory and cardiac muscle involvement. Individuals with a homozygous L276I genotype often develop symptoms in late childhood, progressing to loss of independent ambulation, assisted ventilation, and cardiomyopathy in adulthood. Those with other FKRP genotypes usually experience an earlier onset with a more severe clinical course, rapid loss of mobility by age 20, frequent cardiac involvement, and eventual respiratory failure by age 30.

BridgeBio Pharma, Inc. is a commercial-stage biopharmaceutical company founded in 2015, focused on developing treatments for genetic diseases. The company’s pipeline ranges from early scientific exploration to advanced clinical trials. With a team of experienced drug developers, BridgeBio aims to swiftly apply advances in genetic medicine to benefit patients.