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…