FAQ: What Is Alzheimer’s Drug Leqembi, Where Is It Approved, and More

By The Editors | January 19th, 2024

As of July 2023, Alzheimer's drug Leqembi is fully approved for the treatment of early-stage Alzheimer's disease.

On July 6, 2023, the U.S. Food and Drug Administration fully approved the Alzheimer’s drug Leqembi (generic name lecanemab), a monoclonal antibody drug for people with Alzheimer’s disease. Leqembi got “conditional” approval from the FDA earlier this year, pending more trial data on its safety and efficacy. Last January, the drug received what’s known as accelerated approval from the FDA, based on promising results from the clinical trials that showed it was able to break down beta-amyloid protein build-ups — a hallmark of Alzheimer’s and other neurodegenerative diseases — in the brains of people in early stages of Alzheimer’s disease.

Leqembi is the first disease-modifying Alzheimer’s drug to get full, traditional FDA approval.

With this full approval, the FDA gave its stamp of approval on the claim that the drug also helps preserve memory and thinking in people with early Alzheimer’s. Now, it’s one of two disease-modifying Alzheimer’s drugs to receive any kind of FDA approval. Its predecessor, Aduhelm, still has only conditional approval pending more trial data on safety and efficacy. Patient advocates are celebrating this mark of progress.

(In February 2024, Biogen took Aduhelm off the market indefinitely.)

Leqembi’s drug label contains information about risk factors, like the genetic variant APOE4. (Eisai)

What is Leqembi?

Leqembi is a monoclonal antibody drug that takes a similar approach to its predecessor Aduhelm (aducanumab), targeting beta-amyloid protein clumps in the brain in order to stop and reverse Alzheimer’s-associated cognitive decline. Monoclonal antibodies like lecanemab are designed to target the disease itself by targeting beta-amyloid protein plaques that build up in the brain during Alzheimer’s.

While it has been in the research phase for decades, this “anti-amyloid” approach is a disruptor when it comes to therapies on the market; all other available Alzheimer’s drugs are designed to treat the symptoms of Alzheimer’s, like brain fog, confusion and memory problems.

Where else is Leqembi currently approved by regulatory entities and available to patients?

Leqembi is currently approved in two countries in addition to the US. On September 25th, 2023 the drug was officially approved in Japan. Then early this year on January 9th 2024, the Leqembi was approved in China. Eisai and Biogen are getting ready to launch the drug, and make it readily available in China by the second half of the year.

Health authorities in many other countries and regions are also currently reviewing the drug. 

In Canada, Leqembi has been under review since May 2023 — it can take the agency two years or longer to decide whether to approve a drug. The European Medicines Agency is set to decide whether or not to approve Leqembi by the end of March. It is also under review by the UK’s Medicines and Healthcare Products Regulatory Agency with a decision expected some time this year. It is aso under review in Australia, Switzerland, South Korea, and Israel.

How is Leqembi different from Aduhelm, the last disease-modifying drug to be approved by the FDA?

In principal, the drugs are similar and aim to dissolve or prevent beta-amyloid plaque from forming inside the brain. Lecanemab is targeting an earlier stage of the protein that contributes to the formation of these plaques.

Of note, Aduhelm’s journey has been a rocky one, and not two years after its approval, production and availability have been reduced. Experts and advocates hope for a better outcome for lecanemab.

Does Leqembi (lecanemab) work?

Leqembi is designed to clear amyloid plaque from the brain — an approach the drugmakers believe can actually stop or prevent the cognitive decline caused by Alzheimer’s disease. Scientists still don’t know definitively whether this amyloid protein plaque is the cause of Alzheimer’s, or just a symptom. However, data from the drug’s clinical trials shows Leqembi (lecanemab) was successful in helping to clear these toxic plaques from the brain, improving cognition by a small amount.

Data showed that leqembi’s approach did appear to improve cognitive function in patients by just under half a point (0.45 points) on an 18-point scale. (Some clinician experts have said this may not be enough of an improvement for family members to notice a difference.)

According to Dr. Howard Fillit, co-founder and chief science officer of the Alzheimer’s Drug Discovery Foundation, Leqembi’s full approval confirms that clearing Alzheimer’s biomarker beta-amyloid from the brain does indeed abate Alzheimer’s symptoms to at least a small extent — a benefit that has been called into question as anti-amyloid drugs so far have such a modest impact on Alzheimer’s symptoms.

“This is encouraging news, and more importantly, the approval of Leqembi will serve as a catalyst for driving further developments and investments in the Alzheimer’s pipeline,” Fillit said in a statement at the time of the drug approval in 2023. “We finally have clarity around amyloid’s modest effect on cognitive decline. Now, it is more important than ever to double down and widen our focus to developing the next generation of drugs based on the biology of aging that can lead to a combination therapy and precision medicine approach.” However, he added, we are still in the “early days” of Alzheimer’s treatments.

Where can you get Leqembi?

While Aduhelm is administered by infusion, Leqembi takes a different approach. It is administered intravenously, and other delivery methods are in ongoing trials. Now that the drug has FDA approval, doctors will be able to prescribe Leqembi.

However, monoclonal antibody drugs, this one included, have only been tested among people with mild cognitive impairment or patients in a very early stage of Alzheimer’s. It is still unknown what the impact may be for people in the later stages of Alzheimer’s disease.

These therapies are also quite complicated to produce, and they must be administered by a specialist, which makes them more expensive and not as accessible to people who live far from major metropolitan areas or research universities.

How much does Leqembi cost?

At last check, the cost was approximately $26,500 per year.

Is Leqembi covered by U.S. health insurance?

Yes, with caveats. Private insurance will decide coverage case by case, but they should cover Leqembi because, with traditional FDA approval, it is no different than any other approved drug and there is no generic version available. Learn more about Medicare coverage here.

Does Leqembi (lecanemab) have side effects?

Like its predecessor — monoclonal antibody drug Aduhelm (generic name aducanumab) — lecanemab carries the risk of  side effects including ARIA — brain swelling or brain bleeds. ARIA is often asymptomatic. In rare cases it can be severe.

In the aducanumab trials leading up to Aduhelm’s FDA approval for Alzheimer’s treatment in the summer of 2021, ARIA occurred in more than one third of patients receiving the high dose of the drug. Comparatively, lecanemab appears safer: One in five people who received lecanemab experienced ARIA. Among these cases — only 3.5 percent were symptomatic.

Certain factors may increase a person’s likelihood of an adverse event while taking a monoclonal antibody drug for Alzheimer’s. These include, according to the drugmaker, carrying two copies of ApoE4, or the “Alzheimer’s Gene;” cerebral amyloid angiopathy; and blood thinners (anticoagulants).

The drugmakers have now clarified on the drug’s label who is at most risk of these side effects.

“The clarification in the label of which a segment of the Alzheimer’s population — about 15 percent — has an increased risk of side effects should allow patients and their doctors to have a better-informed conversation, tailored to the particular patient’s situation,” said Vradenburg at UsAgainstAlzheimer’s. “We applaud the company’s commitments to develop and report information about the experience of patients using Leqembi so that the community can continue to learn.”

Up to 80 percent of people with Alzheimer’s have a condition called cerebral amyloid angiopathy (CAA). In CAA, amyloid plaques crowd the brain’s blood vessels, replacing the muscles that normally surround them. Lecanemab and other anti-amyloid antibodies weaken the blood vessels by getting rid of these plaques. The blood vessels become weak and susceptible to hemorrhage. 

People living with Alzheimer’s and CAA might have a higher risk of brain bleeds if they opt for a monoclonal antibody treatment like lecanemab.

According to third-party experts who reviewed cases of lecanemab deaths during the open-label trial extension in 2022, anticoagulant use may have contributed to worsening of ARIA in the first two of three reported deaths from the open label-extension trial.

Is Leqembi safe?

At the time of full approval, Stephanie Monroe, UsAgainstAlzheimer’s Vice President and Senior Advisor for Health Equity, said the FDA approval does mean the drug is safe enough for the general public.

“The scientists at FDA are in the best position to determine whether a drug is safe and effective. Now that FDA has made their decision, it is not appropriate for CMS to second-guess that decision,” Monroe said. “We urge them to keep their word and provide coverage for Leqembi for all populations, including those in the black and brown community disproportionally impacted by Alzheimer’s. Timely and comprehensive access to this therapy is essential for all individuals in need.”

This said, as mentioned, there are a number of factors that increase a person’s risk, and it is the patient’s and their prescriber’s doctor’s responsibility now to understand those factors and that heightened risk, and weigh it against the drug’s potential benefits. It will be up to patients and their doctors to be vigilant for signs of side effects and stay one step ahead.

“Assessment of an individual patient’s risk versus benefit profile is a crucial part of clinical decision making and I hope that the prescribing label for the drug, if approved, will provide detailed guidance on this issue,” Madhav Thambisetty, neurologist and senior clinical investigator at the National Institute of Aging, told Being Patient.

According to Eric Smith, a neurologist at the University of Calgary, patients who receive the drug will need to be monitored through several annual MRI scans and education may be needed to ensure that doctors outside of specialized clinics recognize the signs of ARIA.  

Lecanemab’s trial protocol outlined that safety MRIs should be conducted at nine and 13 weeks of treatment, then every three months for the first six months, and every six months afterward. Lon Schneider, physician and professor of psychiatry at Keck School of Medicine tweeted that a Risk Evaluation and Mitigation Strategy (REMS) may need to be implemented. 

This means that the FDA could also require Eisai and Biogen to develop strategies, like increased monitoring or physician education, to ensure the safety of the patients taking Leqembi (lecanemab).

Additional reporting by Simon Spichack

UPDATE: 3 March 2024, 8:02 P.M. ET: In February 2024, Biogen took Aduhelm off the market, citing financial concerns. Although the drug did receive accelerated, conditional FDA approval for the treatment of early Alzheimer’s disease in 2021, it is no longer available to new patients. The company announced it would sunset trials in May 2024 and cease supplying the drug to current patients in November 2024.
UPDATE, 18 January 2024, 7:05 P.M. ET: This article was updated to include information on where beyond the US. is Leqembi currently approved by regulatory entities and available to patients.
CORRECTION: 3 August 10:25 a.m. ET: This article previously stated in error that the drug was administered by spinal infusion. It is administered by IV infusion.

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9 thoughts on “FAQ: What Is Alzheimer’s Drug Leqembi, Where Is It Approved, and More

  1. The article states the following:
    “The positive data was only announced in a press release issued by the drug companies and has yet to be assessed and published in an independent, peer-reviewed journal.” But “data” is the plural of “datum”. Thus the article should be edited to read as follows:
    “The positive data were only announced in a press release issued by the drug companies and have yet to be assessed and published in an independent, peer-reviewed journal.

  2. It is so unfair,that Medicare,and Medicaid will not support and help your loveone.Why is it always this way. Money,Money Money! This is so sad.😢😰😢🥲😂😅😭

  3. My mother, luckily, got into a trial with Aduhelm so she is getting monthly infusions for no cost. She is about to get #14. She barely made the Cognitive test requirement because she was in later stages than the typical candidate. We know that it has slowed her decline and are so very thankful for any extra time we can get with her still able to recognize us.

  4. plaque is most likely due to incomplete metabolism. We need to address incomplete metabolism and stopping the formation of plaque.

  5. This article is factually incorrect, in that Aduhelm (aducanumab) is NOT administered by “spinal infusion.” It is given by IV, same as Leqembi (lecanemab) with the only difference being monthly infusions vs every two weeks. Important error that you should fix!!!

    1. Hi Patricia, thank you for reaching out. Leqembi was submitted to Health Canada for review in May 2023. According to The Drug Review and Approval Process in Canada, Canada’s drug approval process may take anywhere from six months to two years. In the meantime, access to Leqembi is only available through ongoing clinical trials in Canada. We’ll report on the news as it comes! Thanks for reading.

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