Associated Press | A promising experimental Alzheimer’s disease drug worked no better than a placebo in a late-stage study, an unexpected disappointment after the potential blockbuster stopped symptoms from worsening for a year in a prior test. Pfizer Inc. and partner Medivation Inc. are developing the drug, called Dimebon.

Dimebon failed to meet its primary and secondary goals — improving thinking ability and overall daily function over six months in patients with mild to moderate Alzheimer’s disease, Pfizer and Medivation said on Wednesday.

The news sent shares of Medivation and Pfizer down.