Health Trying to solve the Alzheimer's puzzle
Portsmouth HeraldFeb 05, 2017
Despite a 99 percent failure rate and another major setback last month, Alzheimer’s researchers are plowing ahead with hundreds of experiments — and a boost in federal money — to try to a crack a deadly disease that has flummoxed them for decades.
A law passed by
But billions of dollars have so far made little progress in decoding the memory-robbing disease, which affects 5 million Americans. Alzheimer’s is currently the nation’s sixth leading cause of death. Decades of research have not produced a single drug that alters the disease’s course.
December began with another major setback:
But scientists aren’t giving up on the main hypothesis behind Eli Lilly’s trial: that Alzheimer’s can be defeated by using drugs to attack amyloid “plaques” that build up in the brain of Alzheimer’s patients. Some scientists believe these cause the disease.
Many observers still hold out hope for another promising anti-amyloid drug, Biogen’s aducanumab, which in an early trial improved cognitive decline in a small number of patients.
Other potentially groundbreaking research aims to intervene before patients even feel any symptoms. Using PET scans, scientists can now identify amyloid plaques building up in a patient’s brain years before they develop Alzheimer’s. The A4 study, for instance, is testing solanezumab in adults who are accumulating amyloid plaques, but showing no outward signs of Alzheimer’s, such as memory loss or cognitive decline.
Other scientists are targeting what they believe is the true culprit, the protein tau, which creates “tangles” in the brain, the disease’s other primary marker.
The experiments continue against a bleak backdrop: No new Alzheimer’s therapies have won federal approval since 2003, and Alzheimer’s clinical trials have had a 99 percent failure rate. Patients can access only four
“The history of clinical trials results has been a history of disappointment,” said
Still, 77 Alzheimer’s drugs are currently being investigated or developed, according to the trade group PhRMA. And other experiments seek to repurpose
Non-pharmaceutical solutions are also being explored. Observational studies have shown that people who exercise more and have healthier diets seem to get the disease later in life. Researchers are now conducting trials to more closely measure the effects of exercise and diet. One randomized trial underway at
Even before last month’s passage of the 21st Century Cures Act, public funding for Alzheimer’s research has been rising. The
Meanwhile, Alzheimer’s advocates still grapple with a basic question: Is the rate of Alzheimer’s actually going down? A study in JAMA in November found that even as scientists have made no progress in changing Alzheimer’s course, overall dementia rates, which include Alzheimer’s and other dementias, appear to be dramatically declining. The paper cast doubt over a major talking point of the Alzheimer’s lobby: That as baby boomers age, the number of Americans living with Alzheimer’s will explode from the current 5 million to 14 million in 2050. The study also suggested that lifestyle changes may make a difference.
While some heralded that as good news, others downplayed the finding.
Even if dementia rates drop, Alzheimer’s remains a major killer, and the number of afflicted people will likely still rise, because the
“It’s not time to let our foot up off the gas,” Fargo said.
Eli Lilly’s closely watched trial, dubbed Expedition 3, was the latest potential breakthrough to fall flat. In 2,100 people with mild dementia, solanezumab failed to show significant results compared to a placebo.
Some critics said the failure casts doubt on the hotly disputed hypothesis that Alzheimer’s is triggered by the buildup of amyloid plaques.
But
“Rumors of the death of the amyloid hypothesis have been around for many years, and they’re probably premature,” Fargo agreed.
Fargo noted that brain imaging has shown that amyloid plaques start to build up 15 to 20 years before signs of dementia appear. So to really test the amyloid hypothesis, he said, scientists may have to intervene earlier than they did in Expedition 3.
Despite the latest failure, Fargo said, “there’s still more optimism in Alzheimer’s research right now than there has been for 10 years.”
The answer to Alzheimer’s, Ryan said, is not going to be one “magic bullet,” but an array of solutions tailored to different patients.
Will scientists ever find a cure?
Dr.
“I think slowing the progression and/or delaying the onset, are realistic goals.”
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