Shares of Novo Nordisk (NYSE: NVO) are falling this week, down 33% as of 3:27 p.m. ET on Friday. The drop comes as the S&P 500 lost 2.4%, and the Nasdaq-100 lost 2.2%. The Danish pharmaceutical giant's stock was hit after it released disappointing earnings showing that sales of its blockbuster GLP-1 drugs remain weaker than hoped.

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U.S.-listed shares of Novo Nordisk sank in premarket trading Tuesday after the Danish drugmaker cut its full-year outlook and named a new CEO.