Science and Tech


Why is there no cure for Alzheimer's yet?

Two Alzheimer's drugs have hit the market in the past year and a half: the first treatment since 2003, and the first looking to target the cause.
Posted at 6:12 PM, Feb 17, 2023

A daughter who hasn’t forgotten the day her mother couldn’t remember her:

"I always knew that she knew that we belonged to her," said Connie Lesko, who lost her parents to Alzheimer’s.

A wife and mom who savors each minute she can recall:

"If I could freeze just even today. That would be awesome," said Pam Montana, an Alzheimer's patient. 

Every day loved ones watch as a memory-robbing disease takes their friend, sibling or parent. The person they knew fades away — while still in plain sight. And people like Connie Lesko wonder, "is this gonna happen to me? Am I going to put my kids through this?" 

The answer may never be clear, because doctors don’t have definitive answers as to why people get Alzheimer’s or how to heal them. 

"We need to understand the causes to understand cure," said Stephanie Monroe, the executive director of African Americans Against Alzheimer's.  

The most widely-accepted hallmark of Alzheimer’s starts with a brain protein called amyloid beta. Over time, it can build up into plaques across the brain and lead to speech, thought and memory loss. Another protein called tau can build and tangle up, eventually killing brain cells. But doctors and scientists aren’t sure why either happens.  

There are other theories about Alzheimer’s root cause, like brain inflammation or conditions related to diabetes. 

Advocates say researchers must develop a wider spectrum of treatments. 

"There’s no doubt that this disease is complicated and there are more causes than just amyloid plaques," said Maria Carrillo, chief science officer of the Alzheimer’s Association. "So, anti-tau therapies, anti-inflammation therapies and so many other things have to be explored and will absolutely be required to be used together, to really make a dent in this disease in the future."   

Scientists were hopeful that anti-amyloid drugs would lead to a cure. But many trials for treatments have failed over the years.

In June 2022, drugmakers Genentech and Roche announced their drug Crenezumab didn’t slow nor prevent cognitive decline in its study participants.  

Neurologist Dennis Selkoe, with Harvard Medical School, said the trials were "fraught with missteps" from patient selection to ending trials too early. He believes it’s important to keep developing amyloid-fighting drugs.

Still, scientists are struggling to overcome what’s called the blood-brain barrier.

One Alzheimer's patient's story, as a new drug hits the market

One Alzheimer's patient's story, as a new drug hits the market

Health experts say a new Alzheimer's drug will need longer studies to know how safe and how well it works —especially long term.


The barrier is like the castle wall for our brain, defending it from disease-causing pathogens and other toxins in our blood. The barrier works so well, it's kept a lot of potential drug treatments from reaching the brain — but there’s been progress. Two Alzheimer's drugs have hit the market in the past year and a half. The first treatment since 2003, and the first looking to target the cause of Alzheimer's rather than the symptoms. They’ve brought both criticism and hope. 

"This gives our families hope that they can slow cognitive decline and have more quality time with their loved one before it's in the late stages of Alzheimer's," said Shannon White, chapter executive of the Alzheimer’s Association Greater Kentucky and Southern Indiana.

First, the FDA gave accelerated approval to Aducanumab in summer 2021, under the name brand Aduhelm. This January, the FDA gave accelerated approval to Lecanemab, brand name Leqembi.

They both work by attacking amyloid plaques, at different stages of plaque development. Studies show Leqembi slowed cognitive decline by 27% after 18 months, compared to those who had a placebo. And the FDA said in brain scans, Aduhelm showed to reduce the amount of amyloid plaques. But some experts like neurologist Dr. Andrew Budson think treatments like these are too risky.  

In 2021, he shared his thoughts on Aduhelm. 

"I would not recommend or prescribe this medication. And the reason is that side effects were very common. Approximately 30% of individuals had brain swelling," Budson said. 

New Alzheimer's drug study seeking more diverse volunteers

New Alzheimer's drug study seeking more diverse volunteers

Research efforts try to understand why older Black Americans are twice as likely as older White Americans to have Alzheimer's or other dementia.


Another main criticism — both drugs are costly for patients, costing over $26,000 just for the med. In an op-ed for The Conversation, Todd Golde, who has studied Alzheimer's for over 30 years, noted clinical trials are too expensive and too long. 

He adds it’s difficult for drug manufacturers to justify risking billions of dollars on therapies that may not work. 

Scientists are also trying to figure out timing the start of drug treatments, considering Alzheimer’s can develop 20 years before symptoms show. 

Experts like  Monroe believe the only way to find a cure is to catch the disease before it forms.  

Scientists are now looking for people who have not been diagnosed yet with Alzheimer's in new Leqembi research. It’s called the "Ahead Study." 

"Rather than working to treat symptoms of Alzheimer's disease like memory loss and agitation, is to prevent Alzheimer's disease from its symptoms and trying to delay the actual onset of for Alzheimer's disease," Monroe said. 

Right now, drugs like Aduhelm and Leqembi may only help people who seek treatment as soon as they experience signs of thought or memory loss.  

And a survey from the Alzheimer's Association found 60% of respondents would not see a doctor for signs of mild cognitive impairment.  

For now, doctors say prevention is the best medicine. 

"Continued learning, reading and brain games. And diet and exercise, since cardiovascular health is essential to brain health. Avoiding excess sugars and fats. Exercising to get your heart rate up regularly. And making sure to stay connected and keep your brain active," said Dr. Farshad Fani Marvasti.

Desperate to avoid the same battles her mother fought, Connie Lesko enrolled in a study that tests whether she is at a higher genetic risk for Alzheimer’s. She’ll then have to decide whether to take an experimental drug that’s on the FDA's fast-track for approval later this year. 

"People must participate in clinical trials and not fear them," Lesko said. 

But patients like Pam Montana are long past the point of prevention, making what time, thoughts and memories she has left more valuable than ever.  

"That's really all I want. I just want time," Montana said.