Medicare last week agreed to cover the new drug Leqembi, the first medication proven to slow the progression of Alzheimer's disease, following the U.S. Food and Drug Administration's green light of the pricey drug.

The decision was cheered by the Alzheimer's Association and others who advocate for the 6.7 million U.S. seniors with the progressive disease, which has no cure and which primarily affects people over the age of 65.

The approval to cover the drug is significant because the vast majority of Americans with Alzheimer's get their health coverage through Medicare. Yet some patients and families could still face hurdles in getting access to the medication. For one, Medicare — the health care plan for people who are 65 years and older — won't cover the entire cost of the drug. 

Secondly, Leqembi, pronounced "leh-KEM-bee," might not be appropriate or even accessible for every patient, according to experts. 

Here's what to know about the drug. 

What is Leqembi's price?

Leqembi, from drugmakers Eisai and Biogen, is priced at about $26,500 for a typical year's worth of treatment. 

What is the out-of-pocket cost for Medicare enrollees?

Medicare on Thursday noted that enrollees in its Original Medicare will have to pay a co-payment of 20% of the cost of the drug, after meeting their deductible. 

That means that people on Original Medicare could pay about $5,000 out of pocket annually for Leqembi, according to health-care research group KFF. 

Medicare Advantage enrollees typically also pay 20% of drugs' costs, up to their plan's out-of-pocket maximum, KFF noted, which means that people on these plans may also face high out-of-pocket costs for the medication.

That could prove unaffordable for many Medicare enrollees, as more than half earn less than $30,000 annually.

Will the Inflation Reduction Act help lower costs for Leqembi?

The Inflation Reduction Act, signed into law last year by President Joe Biden, has a provision to cap out-of-pocket drug costs for Medicare recipients at $2,000 starting in 2025 — but unfortunately, the new law won't do anything to help patients who are prescribed Leqembi.

That's because the IRA targets drug costs prescribed through Medicare's Part D, the section that generally covers prescription drugs. But Leqembi is approved under Medicare's Part B, the part of the insurance plan that covers doctor's services. 

Part B covers drugs that generally administered in a doctor's office, like Leqembi, and therefore are considered a doctor's service.

That means the IRA cost-capping provision won't apply to Leqembi's out-of-pocket costs. 

Who is eligible for Leqembi?

Medicare said it will approve coverage of the drug for enrollees:

• Who have been diagnosed with "mild cognitive impairment or mild Alzheimer's disease dementia"
• And who have documented evidence of beta-amyloid plaque, which is present in people with Alzheimer's, on the brain
• And whose doctor participates in a qualifying registry and who has an appropriate clinical team and follow-up care

That means patients with Alzheimer's or impairment beyond the early stages may not be approved for the medication. 

How do patients document beta-amyloid plaque?

Typically, patients will need to undergo additional tests to determine if they have the plaque, which are pieces of protein that band together between neurons in the brain. These tests include either a PET scan or a lumbar puncture, otherwise known as a spinal tap. 

"It's also not clear if insurers will pay for the brain scans and other services necessary to administer the drug," Dr. Mallika Marshall told CBS Boston. 

How is the drug administered?

Patients taking Leqembi must have it administered intravenously in their doctor's office, according to Medicare.

"Patients have to get an infusion every 2 weeks for 18 months, in order to slow the progression of the disease by about 6 months," Marshall told CBS Boston. 

What are the side effects of Leqembi?

"Some patients will experience brain bleeding or swelling" as a side effect, Dr. Marshall said. 

Other reported side effects are infusion-related reactions and headaches, according to the Alzheimer's Association. In a Leqembi study by drugmaker Eisai, 13% of drug recipients had swelling and 17% has small brain bleeds.

"Some patients and families may decide that the benefits don't outweigh the possible risks," Dr. Marshall added.

—With reporting by the Associated Press.

In:
• Alzheimer's Disease