By Janice Lloyd, USA TODAY
Pfizer Inc.'s decision to pull the plug this week on an experimental drug for Alzheimer's disease was a disappointment, but not a big surprise, say medical experts eager for a breakthrough.
The company said Monday that the trial of bapineuzumab is being stopped in patients with mild to moderate symptoms after it failed to change cognitive and functional performances.
"The bottom line of this failed trial is this is part of the process of finding disease-modifying medications," says Bill Thies, chief medical and scientific officer for the Alzheimer's Association. "There will be quite a number of efforts to find the medication we need."
In the past few years, researchers have discovered that symptoms appear as late as seven to 15 years after the disease has started; that may be too late for drugs to make a difference. The current body of research urges starting trials before symptoms appear.
Pfizer did not say if it will continue studies on people with no symptoms.
The decision to terminate the testing of the intravenous drug follows an announcement from Pfizer on July 23 about another group of trials using the same treatment. Those trials also failed, but were done on patients with the ApoE4 gene, which put them at a higher risk of developing the disease. The second trial was done on people without the gene and was expected to have better results.
"We are obviously very disappointed in the outcomes of this trial," said Steven Romano, a spokesman for Pfizer, in a press release. "Yet these data, and the subgroup and biomarker analyses underway, will further inform our understanding of this complex disease and advance research in this field."
The government announced a bold plan in May to find a way to prevent the disease by 2025. The last drug to help manage the disease was developed nine years ago and only offers temporary treatment of symptoms that begin years after the disease takes hold. Meanwhile, 5.4 million people in the nation have the fatal illness, and numbers are expected to spike as the Baby Boomers age.
Pfizer and Janssen Al combined on the trials and will report on analysis of the data at a meeting in Stockholm in September.
Bapineuzumab is one of several experimental drugs designed to target amyloid plaques in the brain. In attempting to understand how the disease progresses, one theory describes the plaques as a mechanism that attacks healthy brain cells, weakening them and eventually killing them. An amyloid drug would target the plaques, similarly to how a statin drug removes plaque from arteries to help prevent heart disease. The other study results are expected in the coming months.
"As we are learning, it is critical that future Alzheimer's drugs be tested in persons before symptoms have appeared and the damage to the brain is so extensive as to be irreparable," says George Vradenburg, chairman of UsAgainstAlzheimer's.
Several "prevention" trials are in development for patients who aren't showing symptoms. For example, The National Institutes of Health committed $16 million in May to a $100 million study to be done on family members who have a genetic predisposition to early onset Alzheimer's.