The first Alzheimer’s drug with a proven impact on the degenerative disease was recently granted accelerated approval by the FDA.
The drug, lecanemab, is currently undergoing clinical trials around the country, including under the supervision of the Glenn Biggs Institute for Alzheimer’s and Neurodegenerative Diseases at UT Health San Antonio.
With some caveats, Klesse Foundation Distinguished Chair in Alzheimer’s and Neurodegenerative Diseases at UT Health San Antonio Dr. Arash Salardini said the FDA's accelerated approval represented a major step forward for Alzheimer’s research.
“This is a new era, honestly. For 100 years we’ve been hitting our heads against the wall, not moving this thing,” Salardini said. “And this is the first sort of demonstration that we can slow it down.”
Salardini said the FDA accelerated approval was expected because lecanemab had much more data supporting its impact on Alzheimer’s than another drug that had received accelerated approval.
“[It’s] a way of FDA saying that, you know, we don’t have a lot that works on Alzheimer’s and we’ve been trying very hard for a very long time, so make this available to as many people as possible because it looks like it is doing something, and we’ll gather data to see how effective it is,” he said.
The FDA will continue collecting data and testing the drug before a potential full approval of lecanemab, which may take months.
The drug works by targeting amyloid, a protein associated with Alzheimer’s.
The drug does have its limitations, explained Dr. Jeremy Tanner, assistant professor of neurology at the Biggs Institute.
“It was really tested in people with mild stages of the disease,” Tanner said. “The evidence is that it might help to slow progression in early stages, but not in the late stages of the disease.”
Tanner also explained its limited effect on Alzheimer’s.
“It didn’t stop decline, and it didn’t stop the disease,” he said. “It just slowed the decline compared to people who didn’t receive the medication. And there’s a debate on how important that slowing is.”
Because the drug is still being tested, Salardini said it’s not yet known how patients will fare once they stop using lecanemab.
“What we don’t know is, once they stop the medication, whether there’s a tail-end effect, where those people continue to do better because they have less amyloid now, or that the effect is just during the time that they’re receiving the medication,” he said.
Then there are the side effects.
“Over 10% of patients, on brain imaging, were shown to have some swelling in the brain and some small hemorrhages in the brain in those who received this infusion,” Tanner said. “The most common side effect was an infusion reaction — most of the time it was mild, but it’s something to know as well.”
According to the research data, 12.6% of patients who received lecanemab had signs of brain inflammation — compared to 1.7% of patients on the placebo — and 20% had signs of some type of hemorrhaging — compared to 9% of patients on the placebo.
Tanner said that even for those who showed brain swelling or small hemorrhages in the brain, the vast majority did not exhibit symptoms, though continued monitoring was necessary.
Salardini added that two patients in the clinical trial died — one during the trial and one after — representing 0.2% of all patients in the trial using the drug.
In addition to questions about the science and side effects of lecanemab, there’s also the question of cost that must be addressed. Currently, the price is so prohibitive that only patients in clinical trials have access.
“The company still has to decide pricing, it has to be evaluated by Medicare and insurance companies to see whether they will support it and cover it, so there’s still many steps involved before even lecanemab would be available for clinical use,” Tanner noted.
Salardini made clear that despite the breakthrough lecanemab represents for Alzheimer’s research, it wasn’t the end.
“You know Churchill’s speech about, ‘this is not the end, this is not the beginning of the end, this is maybe the end of the beginning,’ well that’s where we are at,” he said.
The Biggs Institute continues to seek volunteers to participate in their clinical trial of the drug, in which they are testing the drug’s effects on participants who have the biomarker for Alzheimer’s, but who have not yet begun experiencing symptoms.
Both researchers cautioned that because of the clinical trial design, participants wouldn’t know if they were receiving the real drug or a placebo, and that anyone interested should consult with their doctor before signing up.
CORRECTION: A previous version of this story misspelled the name of the Klesse Foundation. It also misstated the percentage of patients who experienced some type of brain hemorrhaging after receiving lecanemab, according to the research data. It was 20%.
