AstraZeneca shares tumble after Wainua fails heart trial

AstraZeneca shares dropped roughly 9.5% in London trading on Thursday after the drugmaker reported that Wainua did not meet the primary endpoint in a late-stage heart trial, making it the biggest loser on the FTSE 100 that day.

The company released results from the phase-three CARDIO-TTRansform study, which randomised 1,432 patients to receive Wainua or placebo alongside standard care over 140 weeks. The trial’s primary endpoint was a composite of cardiovascular death and recurrent heart-related events. AstraZeneca reported no statistically significant benefit for Wainua in the overall trial population.

Subgroup analyses were mixed. Among the 57% of participants already on stabiliser therapy at entry, Wainua showed no measurable benefit. A subgroup of patients who received Wainua without stabilisers showed a “nominally significant” benefit, the company reported. Wainua was developed in collaboration with US-based Ionis Pharmaceuticals.

Wainua is approved in more than 20 countries to treat polyneuropathy and generated $212 million in revenue for AstraZeneca in 2025. The failed ATTR‑CM readout removes a potential route to expand Wainua’s label into a cardiac indication that analysts had forecast could yield multibillion-dollar peak sales.

Investors reassessed AstraZeneca’s near-term pipeline after the announcement. Citi retained a Buy rating and had projected roughly $6.2 billion in peak Wainua sales for ATTR‑CM, assigning the programme a 59% probability of success. The bank estimated a CARDIO-TTRansform failure would reduce its discounted cash flow valuation for AstraZeneca by about 2.8%, or roughly £5.20 per share from a £181 fair value estimate.

Market attention is turning to other late-stage readouts due later this year, including the SERENA-4 and AVANZAR trials. AstraZeneca has a target of reaching $80 billion in annual revenue by 2030 through launches of up to 20 new medicines.

Sharon Barr, executive vice president of AstraZeneca’s biopharmaceuticals R&D, commented: “Although the trial did not meet its primary objective, we believe the results support greater scientific understanding of treatment approaches for the hundreds of thousands of patients worldwide suffering from this progressive and often fatal condition.”

AstraZeneca did not provide detailed next steps for regulatory filings in ATTR‑CM following the CARDIO-TTRansform result. Analysts and investors will monitor follow-up analyses and upcoming trial data to assess how the outcome affects the company’s pipeline value and long-term commercial prospects.