Key Takeaways:
BridgeBio Pharma jumped 15% on above-average volume after AstraZeneca and Ionis Pharmaceuticals' Wainua failed a Phase 3 trial for a rare heart condition, handing the biotech a competitive advantage in the ATTR-CM market.
BridgeBio Pharma Inc. surged 15.1% to $90.17 on Thursday after a rival's experimental heart drug failed a late-stage trial, strengthening the biotech's position in the $10 billion-plus market for transthyretin-mediated amyloid cardiomyopathy.
"The silencer duopoly is now likely a monopoly — the silencers Coke vs Pepsi race is now just Coke," RBC Capital Markets analyst Luca Issi said in a note.
AstraZeneca and Ionis said their drug Wainua, a once-monthly injection for ATTR-CM, missed its primary endpoint in a Phase 3 study. Adding Wainua to standard treatments failed to improve cardiovascular outcomes, while the Wainua-only arm showed no benefit over existing stabilizers such as Pfizer's Vyndaqel and BridgeBio's Attruby. AstraZeneca shares fell 5.7% to $178.49, while Ionis tumbled 23.9% to $64.27.
The failure removes a potential threat to BridgeBio's Attruby and Alnylam Pharmaceuticals' Amvuttra, which generated $910 million in TTR drug franchise revenue in the latest quarter. BofA Securities analyst Tazeen Ahmad models $4.6 billion in 2026 Amvuttra sales, rising to $10.3 billion at peak in 2033.
How Wainua Missed Its Mark
Wainua was designed as a gene silencer, blocking production of the TTR protein that builds up on heart muscle in ATTR-CM patients. The drug had shown strong TTR knockdown in earlier studies, Morgan Stanley analyst Michael Ulz noted, but high background use of Pfizer's Vyndaqel among trial participants made it difficult to demonstrate a benefit. Ulz maintained his overweight rating on Ionis stock.
Ionis argued that Vyndaqel performed better than expected in the study, contributing to the miss. The company pointed to favorable trends across secondary endpoints and biomarker analyses, though these were not enough to salvage the primary outcome.
Who Wins, Who Loses
BridgeBio stock broke out of a cup base, topping the $84.75 buy point with its relative strength line reaching new highs, according to MarketSurge. Alnylam shares retook their 200-day moving average for the first time since January, though the stock closed 3.3% lower at $312.79.
Alnylam also has a next-generation gene-silencing treatment called nucresiran in development. Ahmad estimates the two drugs could bring in a combined peak of $14.6 billion in 2037, and rates Alnylam a buy with a $460 price target.
Pfizer shares ticked up a fraction to $24.25, reflecting the limited direct benefit to its Vyndaqel franchise, which now faces less competition from Wainua but still competes with BridgeBio's Attruby and Alnylam's Amvuttra.
The trial failure reshapes the ATTR-CM competitive dynamics. Payers may now restrict combining Amvuttra with stabilizers given the lack of benefit shown in the Wainua study, RBC's Issi said. For BridgeBio, the path to capturing market share from Pfizer's entrenched Vyndaqel just became clearer.
This article is for informational purposes only and does not constitute investment advice.
