Leqembi Maintenance Dosing Approved in the U.S.

The U.S. Food and Drug Administration approved Eisai and Biogen’s application for IV maintenance dosing of lecanemab on January 27. Previously, the label called for biweekly IV dosing. The new decision allows physicians to consider transitioning patients to monthly dosing once they have completed 18 months of treatment.

  • IV maintenance dosing for lecanemab will halve the number of infusion center visits.
  • The FDA will decide on subcutaneous maintenance dosing of lecanemab by August.
  • Some patients are opting for donanemab because that treatment has a set end date.

Reaction from clinicians was varied, with some welcoming the news, and others telling Alzforum it will make little practical difference. At University of Texas Southwestern Medical Center, Dallas, Brendan Kelley said several patients there are approaching the 18-month mark. “All have expressed an interest in continuing [treatment], and the lower dosing schedule has been an attractive development for them,” Kelley wrote to Alzforum. Meanwhile, Russell Swerdlow at Kansas University Medical Center, Kansas City, thinks few patients will base their decision of whether to continue treatment on this dosing change. “I would be surprised if one infusion rather than two per month is going to be a game-changer for many people,” he wrote.

Lecanemab was first approved in the U.S. two years ago, and has been covered by insurance for a year and a half (Jan 2023 news; Jul 2023 news). Since then, its use has crept up slowly while clinics put new procedures in place to diagnose, infuse, and monitor AD patients (Jan 2024 news).

Eisai researchers believe continued treatment with lecanemab after plaque clearance will be necessary to maintain the drug’s benefits, with their modeling projecting that monthly maintenance dosing would keep biomarkers at the same level achieved after 18 months (Mar 2022 conference news; Aug 2024 conference news). Based on this, Eisai submitted its application for maintenance dosing to the FDA eight months ago (May 2024 news).

Several clinicians said the approval comes at the right time, with the first patients at their centers about to reach the 18-month mark. At Washington University in St. Louis, one of the first centers to administer lecanemab, that will happen at the end of February; at UT Southwestern, in April. James Noble at Columbia University in New York said most patients there want to continue treatment, and he expects they will appreciate the monthly dosing option. Joy Snider at WashU said the same.

At some centers, patients seem more ambivalent. Ian Grant at Northwestern University in Chicago said many patients there have “infusion fatigue” and do not want to continue indefinitely. Some of them have requested to switch to donanemab, because that treatment has a clear endpoint, he noted. Donanemab was approved six months ago, with its label indicating that treatment can be halted once plaque is gone (Jul 2024 news). “Since donanemab was approved, there have been very few patients who have expressed a preference to start lecanemab over donanemab,” Grant told Alzforum. Kelley agreed, noting that many patients at UT Southwestern are choosing donanemab over lecanemab now.

Some clinicians said they would want to evaluate plaque level via PET scan before deciding whether to transition to lecanemab maintenance dosing. Noble noted that in many cases there will not be a baseline scan to compare this with, because for most patients, clinicians determined initial amyloid positivity via cerebrospinal fluid markers. Nonetheless, he believes a scan would be informative. Snider said that the decision of whether to confirm amyloid clearance via PET may depend on a patient’s insurance coverage. Eventually, plasma biomarkers might offer a better and cheaper option, she noted. “We hope that in the not-too-distant future, we can use these biomarkers to assess treatment response and better predict who would benefit from continued treatment with these therapies,” Snider wrote.

Many clinicians expect that subcutaneous dosing will make a bigger difference to patients than will halving the number of infusions. Eisai completed its application for subcutaneous maintenance dosing in November, and the FDA formally accepted it two weeks ago, with a decision expected by August 31 (Eisai press release).

Meanwhile, overall use of lecanemab and donanemab continues to tick up steadily. At WashU, the number of patients on lecanemab has climbed from 186 six months ago to 287 now. At Yale-New Haven Health, which started administering the drug a year ago, there are now about 200 people on it, Chris van Dyck at Yale told Alzforum. At Kansas University, usage has gone from about 25 people to more than 100 over the last year. Donanemab treatment has only recently begun at most centers, with Snider noting that fewer than 10 patients at WashU are on it yet.

These specialty clinics continue to report few problems with administering anti-amyloid antibodies. Noble noted that one of the main hurdles is getting insurance coverage approved for patients who do not have Medicare. “The medical insurance landscape continues to present unpredictable challenges in coverage determinations for both amyloid PET scans and treatment,” he wrote.

ARIA rates remain similar to those in trials. Kelley said that because UT Southwestern does not treat APOE4 homozygotes, patients there have had less ARIA overall than in trials, with relatively few discontinuations due to ARIA, and no deaths. Recently, researchers in China analyzed data from the FDA’s Adverse Event Reporting System to gather a more global view of lecanemab side effects. As expected, the most common adverse events were ARIA and headache, occurring at a median of 33 days after starting treatment, with an increase in nervous system disorders such as migraines occurring at 42 days (Ge et al., 2025; Xing et al., 2025). Meanwhile, recent case studies of non-fatal hemorrhages in people on the immunotherapy point to possible new risk factors, including subdural hygroma—a buildup of CSF under the dura, often occurring after brain injury—and carrying an APOE2 allele (Watanabe et al., 2025; Ji and Rosenbloom, 2024).

Lecanemab is slowly entering clinics worldwide as well. Ten countries or regions now approve it: China, Great Britain, Hong Kong, Israel, Japan, Macau, Mexico, South Korea, the United Arab Emirates, and the U.S. Meanwhile, the first four countries to approve it—U.S., Japan, China, and South Korea—have started administering the drug. The European Union is expected to approve lecanemab soon, based on a positive recommendation two months ago from the European Medicines Agency's Committee for Medicinal Products for Human Use (Nov 2024 conference news). Australia turned down lecanemab three months ago; Eisai has submitted a request for reconsideration. In addition, Eisai has pending applications in several other jurisdictions, including Saudi Arabia, Brazil, Canada, India, Russia, Singapore, Switzerland, and Taiwan.—Madolyn Bowman Rogers

Comments

  1. None of our patients has completed 18 months of lecanemab treatment, so we do not know how many might express interest in continuing after 18 months of treatment. We think that the reduced dose frequency could make that more attractive for patients. We are discussing this among the MassGeneral Brigham Alzheimer Therapeutic Program team.

    The number of patients continues to grow at MGB. As of today, 406 patients have been prescribed lecanemab and 350 of those have already received at least one infusion. 

    I share this information on behalf of the MassGeneral Brigham Alzheimer Therapeutic Program (MGB-ATP) team

    View all comments by Teresa Gomez-Isla

  2. While we don’t have clear evidence of how long amyloid-lowering treatments, such as lecanemab, should be continued, it makes sense that there would be an induction phase with more frequent dosing and a maintenance phase with a longer interval between doses.

    It is reasonable to talk with patients and families about FDA’s recent approval of moving dosing from bi-weekly to monthly after 18 months of lecanemab treatment. Another strategy is to obtain a follow-up amyloid PET scan at 18 months and talk with patients who have become amyloid-negative about moving toward maintenance treatment.

    View all comments by Stephen Salloway

  3. As a practical matter, this is wonderful news for our practice. We currently have about 10 people who will adopt this dose and many to follow. This frees us up to accommodate new doses, help more people, and provides a goal which is sure to help discussions.

    Having evidence-driven guidance about de-escalating therapy is welcome in other ways. Now that we can get centiloid values at baseline, one could consider a personalized induction approach. Get a PET scan at a year in someone with, say, baseline CL of 40-60s. If negative (and if covered!), then go to monthly dosing. Conversely, for those with high CLs, consider delaying the de-escalation.

    View all comments by David Weisman

  4. The maintenance dose is hugely welcome, but we need FDA approval of the epipen.

    View all comments by Franklin Tseng

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References

News Citations

  1. U.S. FDA Gives Green Light to Leqembi, aka Lecanemab
  2. FDA Grants Traditional Approval to Leqembi
  3. Rising Leqembi Prescriptions Are Straining Clinic Capacity
  4. Using Lecanemab Trial Data to Determine Maintenance Dose
  5. Leqembi: The Case for Long-Term Dosing
  6. Gaining a Foothold: Amyloid Immunotherapy in Clinical Practice
  7. Donanemab Approved in the U.S.
  8. Leqembi: Side Effects No Worse in Clinical Use Than They Were in Trial

Therapeutics Citations

  1. Kisunla

Paper Citations

  1. Ge W, Yan Y, Hu Y, Lin S, Mao P. Unveiling the safety profile of lecanemab: A comprehensive analysis of adverse events using FDA adverse event reporting system data. J Alzheimers Dis. 2025 Jan 12;:13872877241307246. Epub 2025 Jan 12 PubMed.
  2. Xing X, Zhang X, Wang K, Wang Z, Feng Y, Li X, Hua Y, Zhang L, Dong X. Post-marketing safety concerns with lecanemab: a pharmacovigilance study based on the FDA Adverse Event Reporting System database. Alzheimers Res Ther. 2025 Jan 8;17(1):15. PubMed.
  3. Watanabe M, Okochi R, Tezuka T, Ito D. Spontaneous haemorrhage in subdural hygroma in an Alzheimer's patient on lecanemab. BMJ Case Rep. 2025 Jan 8;18(1) PubMed.
  4. Ji S, Rosenbloom M. Intracerebral hemorrhage following mild ARIA-H in an APOE ε2 carrier receiving lecanemab. Alzheimers Res Ther. 2024 Dec 19;16(1):265. PubMed.

External Citations

  1. Eisai press release

Further Reading

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