(AP) -- Federal regulators are again delaying a decision on whether to approve the highly touted experimental anticlotting drug Eliquis developed by Pfizer and Bristol-Myers Squibb.
The drugmakers say the Food and Drug Administration is asking for more information from a huge international study that examined stroke prevention in patients with an irregular heartbeat called atrial fibrillation. The companies say regulators are not asking for any new studies.
Pfizer Inc. shares fell 3 percent and Bristol-Myers Squibb Co. shares lost more than 4 percent in premarket trading Monday.
A Bristol-Myers spokeswoman says the agency could take up to six months to review their response, but they hope it can be completed sooner than that.
The FDA had been expected to make a decision on the drug by Thursday.