BridgeBio Pharma shares rose sharply in pre-market trading, jumping 12.4% after the CARDIO-TTRansform Phase III study of Wainua - developed by AstraZeneca and Ionis - failed to meet its prespecified primary efficacy endpoint. The trial evaluated a composite outcome of cardiovascular mortality and recurrent cardiovascular events over 140 weeks versus placebo, and the negative result is widely viewed as reducing competitive pressure in the rapidly expanding transthyretin-mediated amyloid cardiomyopathy - ATTR-CM - market.
The CARDIO-TTRansform data showed that when Wainua was added to stabilizer-based standard care it did not lower cardiovascular deaths or recurrent cardiovascular events in the overall study population. Subgroup analyses reported a nominally significant benefit only for patients receiving Wainua as monotherapy, while no treatment effect was observed among patients already on stabilizers.
Market participants interpreted the read-through as a clear commercial advantage for BridgeBio’s oral TTR stabilizer, Attruby, which competes directly with Wainua in the same indication. Attruby received FDA approval in November 2024 for adults with ATTR-CM and has seen a rapid commercial ramp. U.S. sales of Attruby reached $362.4 million in 2025, and nearly $181 million in the first quarter of 2026 alone, figures that underscore the product’s early market traction.
The Wainua trial failure had immediate equity-market consequences beyond BridgeBio. AstraZeneca shares fell sharply in early trading, erasing billions in market value. At the same time, Alnylam Pharmaceuticals rallied in sympathy as investors reassessed the competitive landscape for ATTR-CM therapies. In broader-market action, the NASDAQ was modestly higher while the S&P 500 and Dow Jones both declined, with intraday ticker moves showing ALNY +0.59%, AZN -1.99% and BBIO +0.54%.
BridgeBio entered the session with recent positive momentum. The stock had climbed for nine consecutive trading days ahead of the pre-market move, producing a cumulative gain of 13.5% and adding about $1.8 billion to the company’s market capitalization in the run-up to today.
Analysts and investors also note that BridgeBio has additional potential U.S. product launches in its pipeline that could broaden the company’s commercial footprint. The company lists three candidates in the near-term regulatory pathway: BBP-418, which is under FDA review for LGMD2I/R9; encaleret, which has been submitted for autosomal dominant hypocalcemia type 1 - ADH1; and infigratinib, which the company expects to file for achondroplasia in the third quarter of 2026. The failed rival trial is seen as reinforcing BridgeBio’s position within a rare-disease platform-building strategy that combines an approved product with multiple regulatory-stage assets.
Market context and takeaway
The failure of a high-profile Phase III study for a competing therapy has immediate competitive and market implications for firms focused on ATTR-CM. For BridgeBio, the CARDIO-TTRansform outcome appears to strengthen Attruby’s competitive standing in the indication, complementing the product’s recent commercial performance. For AstraZeneca, the negative trial result prompted a sharp investor response. Other companies in the space, including Alnylam, saw share-price movement as the field of late-stage competitors shifted.