TradingKey - On Thursday local time, AstraZeneca ( AZN) announced the failure of a key late-stage clinical trial for its investigational drug Wainua, triggering an 8% pre-market plunge in its US stock price to $173.

Source: Google Finance
The highly anticipated drug is designed to treat transthyretin amyloid cardiomyopathy (ATTR-CM), a rare but life-threatening heart disease affecting approximately 500,000 patients worldwide. The underlying pathology involves the continuous accumulation of misfolded proteins within the myocardium, which ultimately impairs heart function.
However, results from the 140-week clinical trial showed that adding Wainua to the existing standard of care failed to significantly reduce the risk of patient death or the incidence of major cardiovascular complications, failing to meet the pre-specified primary clinical endpoint.
This outcome caught the market off guard, deeply disappointing investors who had previously been generally optimistic about the drug. Morgan Stanley characterized the trial failure as a "significant negative surprise," noting that while the market had doubts about the incremental benefit of Wainua on top of existing therapies, most investors still expected the trial to meet its primary endpoint.
The market's previous risk-adjusted peak annual sales forecast for the drug's cardiomyopathy indication was approximately $3.3 billion. Morgan Stanley expects this figure to be significantly revised downward following the trial results, which could lead to a mid-single-digit percentage reduction in AstraZeneca's long-term earnings forecasts.
Nevertheless, some analysts believe this setback will not derail AstraZeneca's long-term growth targets. An analyst at Jefferies stated that while AstraZeneca's previous expectations for the drug's primary efficacy endpoint and combination therapy efficacy were indeed optimistic, this trial failure will not impact the company's goal of achieving $80 billion in sales by 2030.
AstraZeneca also stated that it will conduct further analysis on the full dataset and plans to formally present the detailed results of the study at the European Society of Cardiology Congress in August.