There was some good news and bad news today about a late-stage test involving a new drug to combat Alzheimer’s disease.
The bad news was the medication that targets the so-called “tau tangles” in a brain affected by Alzheimer’s failed to help 85 percent of people participating in a phase III clinical trial.
However, researchers told participants at the 2016 Alzheimer’s Association International Conference (AAIC) that the drug appeared to help the 15 percent of study participants who weren’t taking any other medications for their disease.
The phase III trial results were the latest in a series of announcements at the conference this week in Toronto.
Other research topics included different diagnosis for men and women as well as smell and eye tests that might be early indicators of Alzheimer’s disease progression.
Like the drug trial results, the scientific announcements were a mixed bag for people hoping for new treatments for a disease that affects more than 5 million people in the United States.
“The science is moving ahead pretty quickly, but it’s not moving quickly enough,” Keith Fargo, Ph.D., director of scientific programs and outreach for the Alzheimer’s Association, told Healthline.
Late stage drug trial
There was a lot of interest in the results of the phase III clinic trial of TauRx Pharmaceuticals’ experimental LMTM drug.
That’s because current approved medications only reduce or slow the symptoms of Alzheimer’s.
The TauRx drug is designed to attack the tau proteins that cause brain tangles in Alzheimer’s patients that affect a person’s memory and cognitive functions.
The 15-month double-blind phase III trial involved 891 people. Of those, 62 percent were women. The average age was 70.
Of the participants, 85 percent were taking other Alzheimer’s medications while 15 percent were not.
Scientists told the AAIC participants that the tau drug failed to improve cognitive or functional skills of the people taking other medication.
However, the scientists said it did reduce the rate of decline in the “monotherapy” patients by up to 85 percent. The reason it helped these participants wasn’t immediately clear.
Despite the overall failure, the scientists said there were some positive takeaways.
“In Alzheimer’s, the most likely scenario for successful future treatment is addressing the disease from multiple angles. Having a drug that targets tau complete a phase III trial is a very hopeful sign,” Maria C. Carrillo, Ph.D., the chief science officer of the Alzheimer’s Association, said in a press statement.
Smell, eye tests
Conference participants this week also heard about potential diagnostic tests for early Alzheimer’s detection involving the nose and eyes.
Researchers from two studies said there appears to be growing evidence that a loss in a person’s sense of smell can be an early indicator of cognitive decline and the possible onset of Alzheimer’s.
In one study, researchers administered an odor test to 397 people who initially did not exhibit signs of dementia. The participants’ average age was 80.
The researchers studied the participants for four years. During that time, 49 participants developed Alzheimer’s.
Researchers said those who scored lower on the initial odor test were more likely to be among those who eventually showed cognitive decline.
In two other studies, researchers studied the connection between Alzheimer’s and the thickness of the retinal nerve fiber layer in the eye.
In one study, more than 33,000 people were surveyed. Researchers said there was a strong connection between cognitive decline and a thinning of that retinal layer.
Fargo said the connection between smell and eyesight to dementia isn’t surprising.
“The senses involve the brain,” he said.
Fargo said these tests could help doctors diagnose Alzheimer’s at an earlier stage before more obvious symptoms appear and significant brain damage occurs.
That would allow patients to begin taking medications and engaging in preventative measures such as exercise when the disease is in its early stages.
This might be of particular help to men.
Researchers noted that two-thirds of people in the United States with Alzheimer’s are women.
Fargo said one explanation has always been that women live longer, but that assumption is now being challenged.
Researchers at the conference reported that it’s possible that a high number of men with Alzheimer’s are not properly diagnosed during their lifetimes.
"This study goes much deeper than just looking at the difference between the number of women and men diagnosed. It calls attention to the process of diagnosis and other lifelong factors that may influence diagnosis and timing and duration of the disease," said Carrillo in a statement.
The state of Alzheimer’s research
Despite recent advancements, Fargo said researchers are still trying to determine the exact causes of Alzheimer’s.
Recent research has focused on the tau tangles as well as the buildup of amyloid plaques in the brain.
Inflammation is another key research focal point, Fargo said, but there are still many unanswered questions.
“It’s not 100 percent clear,” he said.
Fargo said he hopes the avalanche of information on Alzheimer’s doesn’t produce confusion or false hope for families affected by the disease.
“In general, I think the more information, the better,” he said.
Fargo said a major factor in helping advance research is to find people to volunteer for clinical studies.
In particular, he said, people who have family histories of Alzheimer’s but haven’t developed the disease yet can be instrumental in research.
“They are very valuable people for Alzheimer’s disease research,” he said.
While the scientific study continues, Fargo said there are prevention measures people can take to reduce the risk of the disease or at least slowing down its onset.
He said the most important is probably exercise.
“We’ve learned that what is good for the heart is also good for the head,” he said.