Data from BridgeBio Pharma’s Phase 3 FORTIFY study show that BBP-418 significantly increases levels of a key disease biomarker that helps stabilize muscles in patients with limb-girdle muscular dystrophy.
BridgeBio Pharma’s small-molecule drug candidate significantly improved the levels of a key disease biomarker in a Phase 3 limb-girdle muscular dystrophy study, results that analysts say could pave the way for a U.S. launch early next year.
With these findings, announced in a news release on Wednesday, BridgeBio continues “building on the potential of BBP-418 to rapidly improve biomarker levels and functional benefit” in patients with limb-girdle muscular dystrophy (LGMD) type 2I/R9 (LGMD2I/R9), Mizuho Securities told investors in a Wednesday note.
The company is planning to file an application package for BBP-418 with the FDA in the first half of this year, according to BridgeBio’s release, with analysts anticipating a U.S. launch in late 2026 or early 2027.
LGMD 2I/R9 is a monogenic and autosomal recessive subtype of LGMD that manifests as skeletal myopathy of the limbs, followed later by progression into the lung and heart muscles. The condition is caused by mutations in the FKRP gene, weakening its function. This leads to defective alpha dystroglycan (αDG), which under healthy conditions helps stabilize muscles.
BridgeBio’s answer to LGMD 2I/R9 is BBP-418, which works by bombarding the FKRP protein with its corresponding substrate, in effect driving increased function of αDG and improving muscle stability.
In the Phase 3 FORTIFY trial, BridgeBio enrolled 81 patients who were given either BBP-418 or placebo. At three months, the investigational drug nearly doubled the biomarker αDG, which helps measure muscle stabilization in patients, the company reported in October 2025.
Wednesday’s data build on these findings, showing a significant 1.8-times increase in αDG at three months, whereas placebo controls saw “approximately no change” in this biomarker, according to the release. BBP-418 was also able to sustain these “highly statistically significant increases” in αDG through 12 months, BridgeBio added.
William Blair also expressed confidence in BridgeBio’s candidate.
“While FORTIFY was designed to support an accelerated approval pathway using glycosylated αDG as a surrogate endpoint, based on a meeting BridgeBio held with the FDA, the agency has recommended orienting the NDA toward a traditional approval,” the analysts said in a Thursday note to investors.
“We believe [this] is indicative of the strength and consistency of both biomarker and functional efficacy data favoring BBP-418 treatment,” they added.
Mizuho also “observed that the favorable effects of BBP-418 vs placebo start early in the treatment”—as early as three months in. This is true even for clinical outcomes, such as the 100-meter timed test and pulmonary function.
Taken together, FORTFY’s findings “look highly concordant across both efficacy biomarkers . . . and functional measures,” according to Jefferies, which sent out its own investor note on Wednesday. Consequently, the firm stated a 90%+ confidence rate in a full approval for BBP-418 by the end of 2026 or early 2027. Jefferies anticipates at least $600 million in peak sales, noting that this forecast is “quite conservative.”
