UNWELCOME SURPRISE: For a second time, U.S. regulators have delayed deciding whether to approve the highly touted experimental anticlotting drug Eliquis, from Pfizer Inc. and Bristol-Myers Squibb Co.

NEXT STEPS: They're working with the Food and Drug Administration, supplying additional data it wants from a huge study of how well Eliquis prevented strokes in patients with atrial fibrillation, an irregular heartbeat.

PLAYING CATCH-UP: This means Eliquis likely can't be approved until next year, well behind two rival drugs already on sale. Pfizer and Bristol-Myers shares both fell.