Health-care companies fell after growth warnings from two major medical-device makers and a disappointing clinical trial.

Shares of Novartis plunged after one of the company's leading drug candidates failed to show significant progress on a late-stage trial on sufferers of a neuromuscular condition.

Medical-device maker Boston Scientific said it likely would not meet its financial guidance due to the cyberattack that has disrupted its operations.

Shares of Stryker declined after the maker of orthopedic implants and other medical technology said a lack of supply continues to hamper its peripheral vascular business.