Alzheimer’s is a terrible disease. A mind-robber, it steals away everything that makes a patient human — memory, language skills, perception of time and space — and even the ability to feed one’s self. Sufferers are gripped by fear and frustration, as they struggle with everyday tasks and slowly lose their independence. Friends and family are hurt as they helplessly witness how the disease takes their loved one from them bit by bit.
There’s currently no cure for this most common cause of dementia — which affects more than 35 million people worldwide, of which 5.4 million are Americans. There’s yet no drug or treatment to stop it or change its terrible course. The disease worsens as it progresses and ultimately leads to death.
What’s worse, it’s nearly impossible to diagnose before symptoms develop — physical changes in the brain are difficult to detect before clinical signs appear.
Some medical experts believe that drugs for this neurodegenerative disease, being investigated in clinical trials, have failed because the disease in the patients enrolled in such trials has already progressed too far for the drugs to be effective.
This is how the lack of ability to diagnose Alzheimer’s patients reliably in the early stages of the disease has hampered the search for a cure.
Now, a tool that could enable clinicians to detect Alzheimer’s earlier and more accurately in patients — and at the earliest sign of memory problems has just been approved by the U.S. Food and Drug Administration.
The FDA approved on April 6 a much-awaited test developed by Eli Lilly & Co. The test — which is bound to improve treatment and drive the development of medications for the disease — detects the presence of proteins in the brain that are related to Alzheimer’s disease by using a chemical called florbetapir — known by its brand name Amyvid.
One hallmark of Alzheimer’s is a sticky protein called amyloid and Amyvid is a radioactive imaging agent that tags clumps of amyloid, causing them to show up on positron emission tomography or PET scans of the patient’s brain.
Because patients with Alzheimer’s always have some brain plaque, its absence in a test would prompt doctors to look for other causes of mental decline — like depression or medications.
Right now, doctors diagnose Alzheimer’s by observing patients and giving them physical and mental tests to complete — and researchers say the mind-robbing disease could be diagnosed sooner if they could detect amyloid plaques earlier.
• A negative scan indicates that no plaques are present — a finding that isn’t consistent with a diagnosis of Alzheimer’s
• A positive scan means the patient has a moderate to high level of plaques — which may indicate that the patient may have Alzheimer’s disease.
But because plaques are also present in patients with other neurological conditions and are found in older people with normal cognitive function, the test shouldn’t be used to diagnose Alzheimer’s, says Eli Lilly. It can help detect Alzheimer’s — but not diagnose it, the drugmaker explains. The imaging agent is only one tool intended to help find the cause of a patient’s cognitive decline, the company says.
Moreover, if the patient doesn’t experience memory impairment, Amyvid can’t be used to diagnose someone with Alzheimer’s disease because the presence of amyloid in the brain by itself doesn’t suggest that someone has Alzheimer’s.
So how does the test really help?
The test can help doctors provide better early treatment to patients with cognitive decline. Since a negative in the test indicates no clumps or few clumps of amyloid, “that gives the clinician a clue that Alzheimer’s is less likely to be the cause of those symptoms,” explains Dr. Daniel Skovronsky, who developed the agent and is the global brand-development leader for Amyvid at Lilly.
For such patients, doctors can now look for other potential causes of the memory decline — and give the more accurate treatment, he says.
While all this may sound less exact than desired, the truth is, right now doctors can’t make a definitive diagnosis of Alzheimer’s until after the patient dies and an autopsy is performed. And many people who are believed to have Alzheimer’s don’t actually have the disease, Lily tells Bloomberg business.
“There are a lot of patients who have been groping in the dark for some time now, and here’s an opportunity to shine a light in their brain and find out if there’s amyloid or not,” Dr. Skovronsky said.
Moreover, many medical experts say an early hint that someone has Alzheimer’s will improve the success of drugs meant to prevent or delay the progression of cognitive decline. While no medication stops the progress of Alzheimer’s, currently, five drugs are approved by regulatory agencies like the FDA and the European Medicines Agency (EMA) to treat the cognitive decline that comes with the disease. Four of these are acetylcholinesterase inhibitors — Tacrine, Rivastigmine, Galantamine and Donepezil — and the remaining one — memantine — is an NMDA receptor antagonist.
Amyvid to play a key role in treating Alzheimer’s
The new imaging test “is likely to play an important role in learning both how to diagnose and treat the disease,” Denise Park, director of the Center for Vital Longevity at the University of Texas at Dallas tells the Wall Street Journal Health. “But it’s still an open question at this point for asymptomatic people,” she adds. Dr. Park is a behavioral and brain-sciences professor who uses Amyvid in her research on aging of healthy older adults.
Some scientists and doctors swear by the use of florbetapir — and similar agents that are still being developed. They say that such technology will speed up the search for an Alzheimer’s cure by helping to identify more accurately people who are at high risk of developing Alzheimer’s the condition. Identified early, these patients can be enrolled in therapeutic trials. Florbetapir may also be used to track the progression of the disease in the brain.
But just how useful can this be right now, when there aren’t treatments that can significantly alter the course of the disease? Still, some doctors point out that an early diagnosis can help patients and their families plan their treatment. Many patients also just want to know for sure whether they have Alzheimer’s.
Another concern is — can physicians read the scan results accurately and consistently? This concern led the FDA to refuse to approve Amyvid in March 2011. The agency directed Eli Lilly to create a program to help make sure scans using Amyvid could be interpreted correctly.
Since then, the drugmaker has worked with the FDA and experts to develop three-hour online and in-person training programs for doctors.
Amyvid was developed by Avid Radiopharmaceuticals. Eli Lilly bought Avid for $300 million in 2010. The imaging agent will be available in limited quantities starting in June, Lilly said.