Shares of Opko Health Inc. fell more than 8% in premarket trade on Thursday after it said the U.S. Food and Drug Administration informed the company its application for a new drug could not be approved. The company's third-party manufacturer failed to pass inspection, the company said in a statement. The application the FDA declined to approve was for Rayaldee, a new treatment for secondary hyperparathyroidism, but the FDA's observations were not specific to Rayaldee, according to a news release. The third-party manufacturer has said it will respond promptly to the FDA's observations. Opko shares have fallen nearly 25% over the last 12 months, based on Wednesday's close, while the S&P 500 Index has dropped about 1.5%.