The Food and Drug Administration gave full approval to an Alzheimer's drug for the first time in two decades in early July. The drug, Leqembi, showed that it could slow the decline of patients in the early stages of Alzheimer's Disease. The decline was modest, and the drug carries a black box label warning of rare "serious and life-threatening events."

Still, neurologists feel Leqembi's full FDA approval represents hope for Alzheimer's patients and their families. Nearly 6 million people in the U.S. were living with Alzheimer's Disease, the most common type of dementia, in 2020, according to CDC data.

While the full approval of Leqembi may not have come in time for them, one neurologist says time is of the essence and a precious gift to Alzheimer's patients and their families.

"Alzheimer’s can be devastating for patients and their families," says Dr. Marc Lawrence Gordon, MD, a physician specializing in neurology for Northwell Health. "Usually the presenting [symptom] is difficulty with memory…a lot of who we are is 'what do we remember?' A fundamental piece of being who we are is remembering what has happened to us."

Can Leqembi restore that? Not permanently. But here's why it gives doctors treating patients with Alzheimer's hope.

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What Is Leqembi?

Leqembi is the first drug approved by the FDA that changes the course of Alzheimer's Disease, explains Dr. Alvaro Pascual-Leone, MD, a neurology professor at Harvard Medical School, senior scientist at Hebrew SeniorLife and the chief medical officer of Linus Health.

"It does so by changing the amount of amyloid that is built up in the brain of patients with Alzheimer’s disease," Dr. Pascual-Leone explains. "It’s a class of medication called monoclonal antibodies against amyloid. Amyloid is a protein that abnormally builds up in the brain of patients with Alzheimer’s disease."

Dr. Gordon notes that amyloid protein build-up is one of the hallmarks of Alzheimer's, along with tau proteins, or neurofibular tangles. "Amyloid begins developing in the brain before people start developing symptoms of Alzheimer's," Dr. Gordon explains.

Leqembi can help slow down the effects once doctors do diagnose patients in the early stages of dementia. “On average, when they compared people randomly assigned the medication to people assigned the placebo, the slope of decline was less steep in those getting the medication than in people getting the placebo," Dr. Godon says.

And that's a first. "This drug attacks that judicial component of the pathway of disease in Alzheimer’s," says Dr. Leone. "What is exciting is that for the first time, it not only succeeds in cleaning up the amyloid amount, but it also translates into a clinically measurable change in the progression of the disease."

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What Leqembi Doesn't Do

The drug is a breakthrough, but experts say that managing expectations is important. "It does not reverse the disease," Dr. Gordon says. "It is not a cure for the disease."

And unfortunately, patients with Alzheimer's who take Leqembi will still see their condition worsen—just not as quickly.

"Patients who took Leqembi got worse," says Dr. Gordon. "But over 18 months, they did not get worse quite as quickly as those who got the placebo.” Dr. Gordon adds that it is only for patients in the early stages of Alzheimer's disease with mild cognitive impairment or mild dementia due to Alzheimer's.

Related: 23 Ways to Train Your Brain

Why Does Leqembi Have a Black Box Label Warning?

Leqembi has a black-box label, which is the most urgent.

"Leqembi has a black box or 'boxed' warning because it has major safety risks such as brain swelling and bleeding," says Dr. David Merrill, MD, Ph.D.,a psychiatrist and director of the Pacific Neuroscience Institute’s Pacific Brain Health Center in Santa Monica, Calif.

Dr. Merrill says patients taking Leqembi will undergo regular brain scans.

"They may need to stop the treatment because, if treatments are continued, brain swelling and bleeding could result in significant neurologic deficits up to and including death," Dr. Merrill says.

Dr. Gordon notes that the warning allows patients and their families to consider the risks and benefits and providers to recommend it to the right population. For example, people prone to bleeding and swelling or on blood thinners may not be good candidates for Leqembi.

Why Neurologists Are Hopeful About Leqembi

The slope of decline is modest, and there's a black box label warning. Still, neurologists have reasons for optimism about Leqembi.

"Alzheimer’s shortens both lifespan and health span," says Dr. Merrill. "Health span is the time in life we have living free of disabling illness. This drug brings hope that a patient’s health span can be extended."

Dr. Gordon agrees that the quality of life factor is important—for however long it lasts.

"Time is important to all of us," Dr. Gordon says. "It’s really all we have. It’s a matter of having the best quality of time, not just in terms of how long you live but how well you live. The way you can engage with the people around you and the people who love you is something important and precious to us all.”

Time is also a factor in a patient's ability to take Leqembi since it's only for a person in the early stages of Alzheimer's. The drug's emergence creates new reasons for patients and doctors to test for and diagnose the disease proactively.

"It becomes critical to identify patients very early so that they can benefit from this type of medication, and that requires empowering primary care clinicians with the appropriate tools to identify patients early for further evaluation," Dr. Pascual-Leone says.

And the fact that Leqembi was approved lays the groundwork for future, more effective course-changing drugs to help patients with Alzheimer's.

"This is the first medication that has shown, albeit modestly, to modify the course of the disease," Dr. Gordon says. "I don’t think the work is done yet. I think there is a lot more to be done, and hopefully, more medications beyond this that could slow the rate of progression. But now we don’t have the mindset that Alzheimer’s is not something we can change in terms of the course of the disease…this offers a different perspective."

Next up: These Are the Early Dementia Signs That Are Missed the Most Often, According to Neurologists

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