AstraZeneca Shares Slide 9% After Heart Drug Misses Late-Stage Trial Goal

Shares of AstraZeneca fell as much as 9% on Thursday after the British drugmaker announced that its experimental heart treatment Wainua failed to meet the primary endpoint in a late-stage clinical trial, raising concerns over investor confidence despite limited impact on the company's long-term sales outlook.

The company said the study found that Wainua did not significantly reduce deaths or recurrent cardiovascular events over 140 weeks compared with a placebo in patients with transthyretin amyloid cardiomyopathy (ATTR-CM), a rare and life-threatening heart disease.

The trial evaluated the drug as an add-on to standard therapy for ATTR-CM, a condition in which abnormal transthyretin protein deposits stiffen the heart muscle, eventually leading to heart failure.

Analysts at Jefferies said the disappointing result is unlikely to derail AstraZeneca's target of generating $80 billion in annual revenue by 2030. However, they warned that the setback could weigh more heavily on management's credibility after executives had expressed strong confidence in the trial's prospects.

Jefferies estimated the trial outcome could reduce the drug's risk-adjusted sales forecast by around $2.5 billion, adding that investors may question the company's confidence in future late-stage development programs.

Under Chief Executive Pascal Soriot, AstraZeneca has built a reputation over the past 14 years for consistently delivering successful clinical results, particularly in oncology. The unexpected setback is therefore viewed as significant, extending beyond the commercial prospects of Wainua itself.

AstraZeneca said the trial results do not affect the drug's existing regulatory approval for treating hereditary transthyretin-mediated amyloid polyneuropathy (ATTR-PN), a condition in which abnormal protein deposits damage peripheral nerves. The therapy is already marketed in Europe under the brand name Wainzua.

ATTR cardiomyopathy is estimated to affect around 500,000 people worldwide, making it a key area of research for companies developing treatments for rare cardiovascular diseases.