By Vidhi Choudhary A Medicare policy decision might hurt sales of this biotech giant’s Alzheimer’s drug. Alzheimer’s is a cruel disease with no cure.As this brain condition progresses, patients experience greater memory loss and other cognitive difficulties. In “Still Alice,” Julianne Moore’s portrayal of a professor of linguistics at Columbia University, who suffers from the early onset of this debilitating disease without the prospect of a treatment, is hard to watch. More than 6 million Americans suffer from this destructive illness and “barring effective interventions,” this figure could m…