Pfizer gets new patent life for Alzheimer's drug

With the patent on their Alzheimer's drug Aricept expiring this fall, partners Pfizer Inc. and Eisai Inc. have announced regulatory approval for a higher dose of the medicine that will allow a three-year patent extension for the new formulation.

Pfizer's stock price reacted enthusiastically, closing at $15.02 a share, up 44 cents or more than 3 percent.

The U.S. Food and Drug Administration approval came late Friday for the 23 milligram version of Aricept, which clinical studies showed helped Alzheimer's disease patients improve their ability to process information. The new dosage is geared toward patients with moderate to severe Alzheimer's.

New York-based Pfizer said the new Aricept tablets, to be taken once a day, should be available in pharmacies by August, two months before the patent on the 5 mg and 10 mg dosages of the Alzheimer's treatment loses protection in the United States. A generic version of Aricept was approved by the FDA last year.

Pfizer did not respond directly to the question of whether the new formulation would be more expensive than the older version of Aricept.

"Because insurance plans and pharmacy prices differ, the cost to the patient may vary depending on coverage or pharmacy," company spokesman MacKay Jimeson said in an e-mail response to questions. "Patients and caregivers should consult their health care plan."

About 3.6 million Americans over 65 have moderate-to-severe Alzheimer's, Pfizer said in a news release that quoted the Alzheimer's Association. The number with more advanced Alzheimer's is expected to triple in the next four decades, the company said.

By 2050, Pfizer said, about 13.5 million Americans are expected to have Alzheimer's, a disease whose probability of striking doubles every five years for those over 65 years old.

"With the growing aging population and the increasing burden of Alzheimer's disease on patients and their families, it is more important than ever to develop valuable therapies for the treatment of the disease," said Adele M. Gulfo, president and general manager of Pfizer's primary care business unit in the United States.

Japanese drugmaker Eisai, developer and manufacturer of Aricept, currently lists sales of the medicine totaling about $2 billion in the United States. It has acknowledged expecting a big drop in those numbers after losing patent exclusivity in November, but hopes to retain about $800 million in annual sales through a variety of tactics, notably being able to market, through Pfizer, the higher-dose version of Aricept.

The FDA's approval of the new Aricept dosage is based on a study of more than 1,400 Alzheimer's patients. Pfizer has its largest worldwide research-and-development sites in Groton and New London, but local scientists were not involved in the clinical trials, according to a company spokesman.

The trials showed that Aricept at higher doses had statistically significant clinical advantages over the lower-dose alternatives in helping cognition, though it did not improve overall, day-to-day functioning of patients compared with the earlier formulation. The most common side effects were nausea, vomiting, diarrhea and anorexia.

Pfizer said established Alzheimer's patients who have been taking the10 milligram Aricept tablet for at least three months can have their dosage raised to the newly approved 23 milligram level.

"Slowing the decline of cognitive symptoms is important at all stages of Alzheimer's disease," said Martin R. Farlow, a professor at Indiana University School of Medicine and lead author of the new study. "It's important for families to talk with their doctor when they notice a worsening in cognitive function in their loved ones to re-evaluate therapeutic needs."

l.howard@theday.com