The top executives of three major companies are set to appear on Thursday before a Senate panel led by Mr. Sanders, who has made lowering drug costs a signature issue.

Read More Drugs (Pharmaceuticals), Senate Committee on Health, Education, Labor and Pensions, Sanders, Bernard, Johnson & Johnson, Merck & Company Inc, Bristol Myers Squibb Company, Prices (Fares, Fees and Rates), Senate, United States Politics and Government