Novartis and Boston Scientific lead health care sector slide

Novartis shares plummeted following the collapse of a late-stage clinical trial for a key neuromuscular treatment, which failed to demonstrate the necessary efficacy to advance. The setback marks a significant blow to the company's pipeline and investor confidence in its near-term growth strategy.

Simultaneously, Boston Scientific warned that a recent cyberattack has hindered its operations, making it unlikely the company will reach its previous financial guidance. This instability rippled through the broader medical-device market, impacting peers like Stryker, which reported that ongoing supply chain constraints continue to stifle its peripheral vascular business.