Shares of Regeneron Pharmaceuticals (REGN - Get Report) were lower Monday after The Food and Drug Administration put a drug study on hold. Regeneron and partner Teva Pharmaceutical Industries (TEVA - Get Report) had been in a mid-stage study of their experimental drug for chronic lower back pain. As a result of the FDA's decision, Regeneron has completed an unplanned interim review of data and has stopped dosing patients. But the two drugmakers plan to discuss with the FDA a late-stage study for chronic lower back pain.

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