AstraZeneca stock drops 9% after heart drug trial miss deals rare blow to pharma powerhouse

Shares of AstraZeneca fell as much as 9% after a late-stage clinical trial for a heart disease drug failed to meet its target, with analysts saying the bigger issue may be investors' trust in the company rather than the loss of a few extra billion in sales.

Wainua – a medicine AstraZeneca had been testing on whether it could help patients with a rare heart condition – did not reach its main goal of reducing deaths and recurrent heart-related emergencies over 140 weeks compared to a placebo, the British drugmaker said in a press release early Thursday.

It examined how the medicine could help patients with a rare, life-threatening heart condition called transthyretin-mediated amyloid cardiomyopathy, or ATTR-CM, when added to a patient's current treatment plan

Jefferies analysts said the result didn't jeopardise the company's $80 billion sales target by 2030 but noted that AstraZeneca "had been very confident around the primary endpoint and the ability to hit in combination use."

"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 as well as an ability to show utility on top of background therapy," the analysts said, modeling for $2.5 billion less in risk-adjusted sales for the medicine.

Under CEO Pascal Soriot's leadership over the past 14 years, AstraZeneca has developed a reputation as a steadfast powerhouse, especially in oncology. It rarely posts negative trial results, and Thursday's surprise disappointment may have ripple effects beyond the medicine itself.

AstraZeneca confirmed that its existing license for Wainua was unaffected by these trial results. The drug is already approved for treating conditions where misfolded proteins build up, causing nerve damage. It is sold in Europe as Wainzua.

This study examined a specific type of the condition in which misfolded proteins accumulate in the heart muscle, stiffening it and making it difficult to pump blood, and eventually leading to heart failure. It's estimated that about half a million people live with the condition.

AstraZeneca's London-listed shares over the past 12 months.

The stock was last seen down 9.1% in London, on track for its worst day since March 2020 at the start of the Covid-19 outbreak. NYSE-listed shares were down 8.4% in premarket trading.

Shares of Ionis Pharmaceuticals, which is co-developing Wainua in the U.S., plummeted 20% in premarket trading.

In the study cohort, a majority of patients were already on a stabilizer that keeps the protein from misfolding in the first place. Because patients were already receiving treatment for this, adding Wainua – a so-called gene silencer – on top of standard of care didn't show a significant extra benefit to the overall group.

For patients not taking a stabilizer at baseline, Wainua showed a "nominally significant" risk reduction in deaths and heart events compared to placebo, AstraZeneca said.

AstraZeneca is meant to be able to have "exceptionally good trial design ability," and to see the trial fail on design flaws like the percentage of patients on stabilizers, will hit the company's credibility, Jefferies said.

AstraZeneca said that 57% of patients received a stabilizer treatment at baseline, and a further 24% initiated a stabilizer during the trial.

"We would not be surprised seeing people pause for now until the catalyst path is clearer," Jefferies said, noting that the stock may not recover until the next big event for the stock – the AVANZAR trial for cancer – is out of the way.

Citi analysts said it was unlikely AstraZeneca could file for additional approvals for Wainua given the primary endpoint miss, as the Nasdaq-listed Alnylam Amvuttra already has a treatment for ATTR-CM on the market.

Shares of Alnylam Amvuttra were up 17% in premarket trading.

"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," said AstraZeneca Executive Vice President of BioPharmaceuticals R&D Sharon Barr.

Full data will be presented at the European Society of Cardiology in August.