The AstraZeneca Wainua trial failure sent the drugmaker’s shares down 10% on Thursday, dragging the FTSE 100 lower and leaving the UK benchmark as the only major European index to close in negative territory.
The decline wiped around £20bn from AstraZeneca’s market capitalisation, a sum larger than the individual market caps of two-thirds of FTSE 100 constituents. Gains in miners, banks and technology stocks were not enough to offset the damage from the index’s second-largest constituent.
Inside the AstraZeneca Wainua Trial Failure
Wainua (eplontersen) is an RNA gene-silencer co-developed with AstraZeneca and Ionis Pharmaceuticals. The drug was already approved for transthyretin amyloidosis with polyneuropathy, a condition where proteins misfold and accumulate in the body, and the trial was testing whether it could expand into a second indication.
According to AstraZeneca’s Form 6-K filing, the CARDIO-TTRansform Phase III trial enrolled 1,432 participants across 20 countries. Patients received either 45 mg of Wainua or a placebo every four weeks, with the trial testing reduction of cardiovascular mortality and recurrent cardiovascular events through Week 140 in adults with transthyretin-mediated amyloid cardiomyopathy (ATTR-CM).
The trial missed its primary endpoint. Full data will be presented at the European Society of Cardiology Congress in August 2026.
Dan Coatsworth, head of markets at AJ Bell, said the update was sharper than investors had hoped. ‘AstraZeneca’s latest update was more bitter than sweet as it said the drugs don’t work,’ he said. ‘A setback for a promising treatment knocked its share price for six and acted as a major drag on the FTSE 100. It meant the UK market was the only major European index to be in the red as others including the Dax and CAC 40 staged a comeback after yesterday’s miserable session.’
Jefferies Cuts Sales Forecast but Leaves 2030 Target Intact
Jefferies analyst Michael Leuchten modelled $2.5 billion less in risk-adjusted sales for Wainua following the trial miss, according to CNBC. Leuchten said the failure does not endanger AstraZeneca’s $80 billion sales target for 2030.
He said the ‘bigger issue is probably a degree of credibility loss with management being very confident in the trial’s ability to hit the primary endpoint.’
Bloomberg, reporting via Yahoo Finance, noted the failure relates specifically to the attempted label expansion into cardiomyopathy rather than Wainua’s existing approved use.
AstraZeneca reported total revenue of $58,739m for FY 2025, up 8% at constant exchange rates, with Core EPS of $9.16, up 11%, according to its full-year and Q4 2025 results announcement. The trial setback therefore lands on a company still generating strong underlying growth.
Miners Rallied, but Gains Were Overshadowed
Anglo American, Antofagasta, and Glencore all rose around 3% as President Trump signalled openness to negotiations. The moves came after a night of strikes across the Middle East.
Susannah Streeter, Chief Investment Strategist at Wealth Club, said investors were reading the signals carefully. ‘Investors are assessing the likely outcome of the latest round of military action, with both Iran and the US hitting targets in the region. While President Trump has declared the ceasefire to be over, he’s already been heard talking on Air Force One about the prospect of a deal and whether he’s inclined to talk to Iran,’ she said.
‘It already seems that a door may be opening to fresh negotiations, even though both sides continue to talk tough. Oil prices have retreated slightly, with Brent crude hovering around $77 a barrel, down from above $80 yesterday.’
Streeter added that mining stocks had rebounded as easing oil prices reduced inflation concerns and pushed the dollar lower, making commodities priced in the currency more attractive to international buyers.
Computacenter, a recent addition to the FTSE 100, was the session’s top riser, with shares up 7% after the company demonstrated AI-driven profit and revenue growth.
The next catalyst for AstraZeneca is the ESC Congress in August 2026, where full CARDIO-TTRansform data will be disclosed. Market participants will be watching for any signal of whether the company pursues further development in ATTR-CM or redirects resources.
