BridgeBio Pharma (BBIO) has a clear path to a potential approval this month for its limb-girdle muscular dystrophy Type 2I/R9 drug candidate, which would be the first disease-modifying therapy for the rare neuromuscular condition. The FDA has set an action date of November 27 for the drug, BBP-418, under priority review and without a scheduled advisory committee meeting.
BridgeBio executives and analysts are confident of approval given the strength of the evidence and the unmet medical need. “This is a profound opportunity to change the course of disease,” said Christine Siu, chief executive of BridgeBio’s neuromuscular division, “since our drug demonstrated meaningful improvements in both the ability to walk faster and breathe better.”
Patients with the chronic, progressive disease lose function over time and become wheelchair-bound between their 20s and 40s, depending on its aggressiveness, Siu said. The condition also causes cardiac and respiratory disease, which can be fatal. It is caused by a mutation in the FKRP gene that impairs glycosylation and ultimately damages muscle. BBP-418, an oral glycosylation substrate therapy, is designed to raise levels of glycosylated alpha-dystroglycan, a common biomarker for the disease.
Andrew Tsai, an analyst at Jefferies (JEF), puts the odds of approval by the deadline at more than 90 per cent, based on results from the Phase 3 FORTIFY study. The trial enrolled 112 patients aged 12 to 60 and met its primary interim endpoint, showing a statistically significant increase in glycosylated alpha-dystroglycan versus approximately no change on placebo at three months. It also met its secondary endpoints, including a reduction in serum CK, a marker of muscle damage. Exploratory 12-month data suggest cardiac benefits, with all treated patients returning to the normal range for the heart injury marker troponin I.
The drug is not merely slowing decline, Tsai said. “You’re actually getting improvement,” he added. “It feels pretty darn compelling.” Treated patients completed a 100-meter timed test 31 seconds faster than those on placebo after 12 months. Siu said that gap is the difference between walking independently in the community and being confined to the home, and recounted how one trial participant walked at her high school graduation after previously using a wheelchair.
Tsai said the absence of an advisory committee is probably a good sign, suggesting the FDA sees nothing in the data to probe and finds it convincing. He added that approval could bring BridgeBio to profitability by the fourth quarter of 2027.
BBP-418 would be the company’s second launch. Its only commercial product, Attruby for transthyretin amyloid cardiomyopathy, has been a widespread success since its 2024 approval, and BridgeBio has built a similar commercial operation for the new drug. “We have our sales force. We have our medical science liaisons, our field reimbursement managers, and they’re all trained and in the field already,” Siu said. The initial market is concentrated at about 150 Muscular Dystrophy Association centers, she said, and the response has been very positive.
BridgeBio has identified more than 500 prospective US patients, with potentially thousands more given adequate genetic testing and diagnosis. Tsai said that could make the opportunity worth more than $1bn a year at peak. Worldwide, there are more than 7,000 patients, about 3,000 of them in the US and between 4,000 and 5,000 in Europe, particularly Scandinavia, where the causative mutation has genetic roots. The European Medicines Agency has granted the drug orphan designation.
Pricing has not been disclosed. Tsai modeled an annual list price of about $400,000 but said “people ultimately would not be surprised if it were priced at $1 million plus,” noting BridgeBio’s pricing power as the owner of the first and only treatment in the field. Siu said she expects pricing in line with other rare neuromuscular drugs, and that payers have been receptive to the functional data. Payers are likely to require genetic testing for coverage, and Siu expects that to appear on the label, though she does not see it as an obstacle because two sponsored broad neuromuscular panels are available free of charge.
Longer term, BridgeBio hopes to extend the label to other limb-girdle subtypes, including types 2M and 2U, and to children under 12 with the 2I/R9 subtype.
Rivals are also pursuing treatments. Sarepta Therapeutics (SRPT) is developing its remaining investigational gene therapy, SRP-9003, for a different subtype, LGMD2E/R4. Phase 3 results in October 2025 showed it raised expression of the beta-sarcoglycan biomarker by 23.9 per cent in non-ambulatory patients and 43.4 per cent in those able to walk. Bayer’s (BAYRY) AskBio unit is developing a gene therapy, AB-1003, aimed at the same 2I/R9 subtype as BBP-418, which showed an acceptable safety profile in a Phase 1/2 trial last October. With a decision weeks away, however, Tsai said BridgeBio sits comfortably in pole position.