A drug is finally available to slow Alzheimer’s. How are the patients doing?

Over the past three years, a new class of Alzheimer’s drugs, the first to address a root cause of the disease, has set off a rollercoaster of hope and disappointment. But while these so-called anti-amyloid antibodies got off to a rocky start, many patients and their doctors are feeling more optimistic now that one of the drugs is finally becoming more widely used.

Lecanemab (brand name Leqembi; pronounced le-KEM-bee) was granted full approval by the Food and Drug Administration in July 2023 and is currently the only one in its class available for Alzheimer’s patients outside of clinical trials. The drug has been shown to slow the progression of the disease, but its benefits are quite modest. It is also a heavy therapy and has a high risk of disturbing side effects.

With lecanemab having been approved for nearly a year — and with a similar drug, donanemab, recommended for approval by an FDA advisory committee at a meeting Monday — the New York Times checked with experts at three major medical centers to see who gets lecanemab and how they are responding.

Who is lecanemab prescribed for?

There are strict requirements for patients to be eligible for lecanemab; by one estimate, less than 20 percent met the qualifications for the medication. Neurologists at the Mayo Clinic, Massachusetts General Hospital and the University of California, San Francisco all described a similar review process when deciding which patients are good candidates.

First, the patient must be diagnosed with mild cognitive impairment or mild dementia, the two earliest stages of Alzheimer’s disease. Second, because lecanemab works by removing the amyloid plaques that are a hallmark of the disease, patients undergo a PET scan or a lumbar puncture to make sure the plaques are actually present in the brain. Third, the patient needs an MRI to check for signs of other brain diseases.

“We want to make sure they don’t have another explanation for their cognitive problems,” said Dr. Ronald Petersen, director of the Mayo Clinic Alzheimer’s Disease Research Center.

Hospitals also require genetic testing for the APOE4 gene variant, because having two copies of it significantly increases the risk of serious side effects, especially brain swelling and bleeding. Some medical centers automatically exclude patients with two copies of the gene; others allow it but will advise the patient of the increased risks. Another reason not to give patients the drug is if they are taking a blood thinner, which also increases the risk of serious brain bleeding.

Even if a patient meets all these criteria, doctors still cannot prescribe lecanemab. The person may have other health problems or may live far from a hospital with an MRI, which is necessary to evaluate patients if they suddenly start experiencing severe side effects.

In each case, a panel of neurologists, radiologists, psychiatrists, geriatricians and other experts vote on whether they think the patient qualifies.

“It’s really a multidisciplinary approach,” said Dr. Gil Rabinovici, a professor of neurology at UCSF “We think very carefully about each patient and make decisions ideally by consensus about who is appropriate.” Since UCSF began administering lecanemab last fall, the hospital has treated several dozen patients with it, with roughly 60 percent of people meeting the screening criteria ultimately approved by the panel.

What does the treatment involve and what are the risks of the medication?

Eligible patients and their families also have a lot to weigh.

On a practical level, lecanemab can be time-consuming and expensive. Patients must come in for infusions every two weeks, plus regular MRI scans to monitor for side effects. And while the drug is 80 percent covered by Medicare, the treatment and multiple doctor visits it requires can still add up to $6,600 a year in out-of-pocket costs, according to one estimate.

“For them to travel, to take a day off every two weeks,” that’s a lot for patients and their family members, said Dr. Liliana Ramirez Gomez, clinical director of the Division of Memory Disorders at Massachusetts General Hospital.

People also need to consider the risks. The main concern with lecanemab is a condition known as ARIA, for amyloid-related imaging abnormalities, which can cause brain swelling or bleeding. During a clinical trial, these side effects occurred in anywhere from 5 percent to 39 percent of patients, depending on the person’s APOE4 status, although they often had no symptoms. Of the more than 1,600 patients who received a dose of lecanemab, four deaths were possibly related to the drug.

There have been cases of ARIA in all three medical centers, but so far none has been serious. “I don’t think the manifestation of side effects has been as troubling as some might have predicted,” said Dr. Petersen.

What are the benefits and how are initial patients responding?

Along with these risks and burdens, the potential benefit of taking lecanemab is, on average, a 27 percent slowing of the disease. The drug won’t improve people’s memory, but it delays the progression of Alzheimer’s by about five months.

It helps people stay “in their current early stage for longer,” said Dr. Rabinovic. “It’s delaying the time when they need help with basic activities of daily living.”

Most patients of Dr. Rabinovic who take lecanemab have only been taking it for a few months, so he said they are still in “wait and see” mode to gauge the benefits.

Despite their concerns, experts said many of their patients — and their doctors — were enthusiastic about the medication.

“Alzheimer’s disease is a devastating condition for patients, for their families, so people are actually very excited, eager to get this treatment,” said Dr. Ramirez Gomez. “On the physician side, I think there’s a sense of optimism, too, to a certain extent.”

This is how Helena and her husband, Jozef, feel. When Helene was diagnosed with mild cognitive impairment due to early-onset Alzheimer’s disease at age 61, she and Joseph immediately began researching potential treatments and clinical trials. (Both asked to use middle names to protect their privacy.)

After completing all the required tests, they learned that Helene was a good candidate for lecanemab and decided to pursue the treatment. While they’ve faced some obstacles — struggling to get Joseph’s insurance to cover him, a 90-minute round trip to the infusion center, a bad reaction after the first dose — the process has been worth it. Helene has had no problems with brain swelling or bleeding and has not progressed to the next stage of the disease.

“You have to take a leap of faith that the science is out there,” Joseph said. “There are risks, but we think we’re managing those risks pretty well.”

“From a selfish point of view,” he added, “I just want it longer.”