Pfizer Inc and Medivation, Inc announced results from two phase-3 trials of the investigational drug Dimebon (latrepirdine) in patients with Alzheimer's disease (AD). In the Connection trial, Dimebon did not meet its co-primary or secondary efficacy endpoints compared to placebo. Co-primary endpoints were measures of cognition and global function.

"The results from the Connection study are unexpected, and we are disappointed for the Alzheimer's community," said Dr David Hung, president and chief executive officer of Medivation. "We are working with our colleagues at Pfizer to better understand the Connection data and we plan to present these data at an upcoming medical meeting."

Dimebon was well tolerated in both the Connection study and in a separate phase-3 safety and tolerability study, which confirmed Dimebon's tolerability when dosed alone or in combination with approved Alzheimer's disease medicines.

"We are evaluating the Connection data with Medivation. After that review, Pfizer will be in a position to determine appropriate next steps regarding the Dimebon programme," said Dr Briggs W Morrison, senior vice president, clinical development, Primary Care Business Unit at Pfizer. "We recognize the significant medical need, and we are committed to advancing treatment options for Alzheimer's disease."

Dimebon (latrepirdine) is an investigational oral medication being tested as a potential treatment for Alzheimer's disease and Huntington disease.