AstraZeneca shares slide after Ionis-partnered drug fails late-stage heart disease trial

AstraZeneca shares fell after its Ionis-partnered drug Wainua failed to meet a primary endpoint in a late-stage trial for heart disease. The July 9 Reuters report says the company’s nerve disease medicine, tested in transthyretin-mediated amyloid cardiomyopathy (ATTR-CM), did not significantly reduce cardiovascular deaths and recurring heart problems when added to standard care. The setback undercuts what analysts had projected as a potential $2 billion peak-sales opportunity. AstraZeneca’s stock was down more than 9%, falling 9.5% by 0709 GMT and becoming the biggest decliner on the FTSE 100. The trial, CARDIO-TTRansform, enrolled 1,432 patients and ran for 140 weeks versus placebo. Wainua had no effect in 57% of participants already on stabilizer therapy, but a subgroup taking it alone showed “nominally significant” benefit. Wainua generated $212 million in revenue in 2025 and is already approved in over 20 countries for polyneuropathy.