Outside experts have said data from two halted trials don't prove the drug is effective. Regulators pushed back the decision deadline to June 7, at latest. The Food and Drug Administration is delaying its decision deadline for Biogen and Eisai's hotly debated Alzheimer's disease drug, a move that analysts said bodes well for Biogen. Cambridge, Massachusetts-based Biogen said Friday that the FDA's decision on its drug aducanumab has been pushed back by three months, moving the deadline from March 7 to June 7. Biogen attributed the change to new data and analysis it had provided to regulators, which was considered a "major amendment" to its application.