Pfizer drug Dimebon fails in Alzheimer's trials

Pfizer Inc. announced today that its experimental drug Dimebon failed to show signs of effectiveness in improving cognition or overall functioning of patients with Alzheimer's disease.

The announcement, based on two late-stage clinical trials, was a surprise in light of previous reports in mid-stage trials of significant improvements seen in Alzheimer's patients. The so-called CONNECTION study looked at the effect of Dimebon on patients with early- to mid-stage Alzheimer's at doses of 20 mg and 5 mg, but found no significant effect at either level.

Pfizer, including scientists at company campuses in Groton and New London, had been developing Dimebon along with partner Medivation Inc.

"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."

"We are evaluating the CONNECTION data with Medivation," said  Briggs W. Morrison, Pfizer's senior vice president for clinical development in its Primary Care Business Unit. "After that review, Pfizer will be in a position to determine appropriate next steps regarding the Dimebon program."

Pfizer paid Medivation an initial $225 million for the rights to develop and market Dimebon, with payments of as much as $725 million if the  drug proved effective.

Dimebon also has been cited as a possible treatment for Huntington's disease.

Some analysts had put the potential market for Dimebon at $1.5 billion. But Les Funtleyder, a healthcare analyst for Miller Tabak & Co., said in a note this morning that he had not projected any revenue from the experimental drug, given the track record of other potential Alzheimer's treatments.

Funtleyder said he was more focused on reports that Pfizer was in a bidding war for German generics manufacturer Ratiopharm.

"Pfizer has been expanding its presence in generic markets across the globe but this ould be the largest foray into the area," he said. "Despite our reservations about Pfizer, we think this is a smart move as it further diversifies PFE and the composition of the German generic markets plays into PFE’s marketing strength."

In early-morning trading, Pfizer's stock was off 15 cents, or less than 1 percent, to $17.60.