U.S. Food and Drug Administration (FDA) Grants Accelerated Approval to Aducanumab for Alzheimer's Disease (2021)

Table of Contents

1. What the U.S. Food and Drug Administration Did on June 7, 2021
2. The Medicine and Why It Was Called a First
3. What Accelerated Approval Means
4. The Basis: A Reduction in Amyloid Beta Plaques
5. The Expedited Review Programs the Application Used
6. The Path to the Decision: Application and Advisory Committee
7. How Other Federal Bodies Took Up the Approval in 2021
8. What the Approval Did Not Do
9. Dates and Legal Status as of October 18, 2026
10. How It Fits Later U.S. Food and Drug Administration Alzheimer’s Actions
11. Primary Documents
12. Key Research Papers
13. Connections
14. Featured Videos

1. What the U.S. Food and Drug Administration Did on June 7, 2021

The U.S. Food and Drug Administration’s list “Novel Drug Approvals for 2021” records aducanumab-avwa as the 26th novel drug approval of the year, approved on June 7, 2021, with the U.S. Food and Drug Administration-approved use given as “To treat Alzheimer’s disease.” The approval was made by the U.S. Food and Drug Administration’s Center for Drug Evaluation and Research (CDER), and the year-end CDER report lists it as an injection.

The application was a biologics license application (BLA), the type of application used for biological products such as antibodies, numbered BLA 761178. A later U.S. Food and Drug Administration notice in the Federal Register (the U.S. government’s daily publication of rules and official notices) states that the U.S. Food and Drug Administration verified that this application “was initially submitted on July 7, 2020” and “was approved on June 7, 2021.”

CDER’s report on the year, “Advancing Health Through Innovation: New Drug Therapy Approvals 2021,” describes the decision in one sentence: “Using the accelerated approval pathway, CDER approved a new drug to treat Alzheimer’s disease.”

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2. The Medicine and Why It Was Called a First

Aducanumab is an antibody, a laboratory-made immune protein, approved as a biological product. It is a monoclonal antibody, designed to attach to one specific target. The U.S. Food and Drug Administration’s 2020 advisory committee notice describes it as “aducanumab solution for intravenous infusion,” and the U.S. Food and Drug Administration’s 2024 notice ties its approval to a reduction in amyloid beta plaques, the protein deposits at the centre of this approval (section 4).

CDER’s 2021 report makes two claims about it:

• “This drug is the first new treatment approved for Alzheimer’s disease since 2003 and the first therapy that targets the fundamental disease pathophysiology.” (Pathophysiology means the disease process itself, as opposed to its symptoms.)
• It was one of the 27 of the year’s 50 novel drugs (54%) that CDER identified as first-in-class, which the report explains as drugs that “have mechanisms of action different from those of existing therapies.” The report’s list entry reads: “This drug is the first therapy for Alzheimer’s that targets the fundamental disease pathophysiology.”

These are CDER’s own descriptions. Whether removing amyloid plaques changes the course of the illness for patients is the question that accelerated approval left to the confirmatory trials (sections 3 and 4).

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3. What Accelerated Approval Means

In its 2021 report, CDER explains accelerated approval this way: the program “aims to bring drugs that can provide important treatment advances sooner to market than with traditional approvals.” It gives the U.S. Food and Drug Administration “more flexibility in what endpoints can be used to approve a drug that offers a benefit over current treatments for a serious or life-threatening illness.”

The key difference lies in what has to be shown. In CDER’s words, accelerated approval endpoints “may include those that are reasonably likely to predict clinical benefit, which may enable the drug to show benefits over a shorter treatment duration (whereas longer-term demonstration of benefit is needed for traditional approval).” The report then states the condition that comes with it: “Subsequent confirmatory trials must be conducted to support traditional approval.”

An endpoint is the measurement a clinical trial uses to judge whether a treatment works. A clinical benefit is a change patients experience directly, such as slower memory loss or better daily functioning. A surrogate endpoint is a marker, such as a lab value or a brain scan, that is expected to predict that kind of benefit.

Aducanumab was one of 14 of the 50 novel drugs (28%) that CDER approved under accelerated approval in 2021.

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4. The Basis: A Reduction in Amyloid Beta Plaques

The U.S. Food and Drug Administration states the basis of the approval in a 2024 Federal Register notice: the Alzheimer’s disease indication “is approved under accelerated approval based on reduction in amyloid beta plaques observed in patients treated with” the product. The same notice adds: “Continued approval for this indication may be contingent upon verification of clinical benefit in confirmatory trial(s).”

Put plainly, the U.S. Food and Drug Administration’s own wording ties the 2021 approval to a surrogate endpoint, the plaque reduction seen on testing, and leaves the question of benefit to patients to trials still to come. The history of the amyloid hypothesis behind this approach is told on the site’s Alzheimer’s Disease: History and Discovery page.

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5. The Expedited Review Programs the Application Used

The U.S. Food and Drug Administration has several programs meant to speed the development or review of medicines for serious conditions. CDER’s 2021 report lists aducanumab under the following:

• Fast Track. The report explains that Fast Track “speeds new drug development and review by increasing the level of communication between U.S. Food and Drug Administration and drug developers and by enabling CDER to review portions of a drug application on a rolling basis.” Aducanumab was one of 18 novel drugs of 2021 with this status.
• Priority Review. A drug receives Priority Review, the report says, “if CDER determines that the drug could potentially provide a significant advance in medical care,” and CDER then aims to act on the application within six months of filing, compared with 10 months under standard review. Aducanumab was one of 34 such drugs.
• Accelerated Approval (section 3).

It was not among the 14 drugs of 2021 designated Breakthrough Therapies. The same report also lists aducanumab among the 43 novel drugs approved on the “first cycle” of review, among the 49 approved on or before their goal date under the Prescription Drug User Fee Act (the law under which companies pay fees and the U.S. Food and Drug Administration commits to review deadlines), and among the 38 approved in the United States before any other country.

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6. The Path to the Decision: Application and Advisory Committee

• July 7, 2020. The biologics license application is first submitted, according to the U.S. Food and Drug Administration’s 2024 regulatory review period notice.
• September 29, 2020. The U.S. Food and Drug Administration announces in the Federal Register (85 FR 61013; Docket No. FDA-2018-N-0410) a meeting of its Peripheral and Central Nervous System Drugs Advisory Committee. The notice describes the committee’s general function as providing “advice and recommendations to U.S. Food and Drug Administration on regulatory issues,” and opens a public docket for comments.
• November 6, 2020. The committee meets virtually. The notice states that the committee “will discuss biologics license application (BLA) 761178, for aducanumab solution for intravenous infusion … for the treatment of Alzheimer’s disease.”
• June 7, 2021. The U.S. Food and Drug Administration approves the application.

A Federal Register docket is the public file for an action, where documents and public comments are kept on regulations.gov. The U.S. Food and Drug Administration documents read for this page do not record the committee’s votes or advice, so this page does not report them.

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7. How Other Federal Bodies Took Up the Approval in 2021

Two Federal Register notices from other parts of the U.S. Department of Health and Human Services (HHS) show the approval being discussed across government later in 2021:

• The Advisory Council on Alzheimer’s Research, Care, and Services (U.S. Department of Health and Human Services), which “provides advice on how to prevent or reduce the burden of Alzheimer’s disease and related dementias on people with the disease and their caregivers,” announced on June 29, 2021 (86 FR 34242) that at its July 19, 2021 meeting it would “discuss the implications of and opportunities presented by the approval of aducanumab.”
• The Centers for Medicare & Medicaid Services (CMS), in its November 17, 2021 notice of the 2022 Medicare Part B premium and deductible (86 FR 64205), listed among the most important factors in setting its reserve for 2022 “the impact on program spending of” aducanumab, which it called “the drug newly approved by the Food and Drug Administration (U.S. Food and Drug Administration) for treatment of Alzheimer’s disease.” The notice also refers to “the unusually high degree of uncertainty for program costs due to the drug” and the COVID-19 pandemic. The notice set the standard monthly Part B premium for 2022 at $170.10, up from $148.50 in 2021.

Medicare Part B is the part of the U.S. Medicare program that covers doctor-administered treatments, including drugs given by infusion in a clinic. The stated purpose of the CMS notice is to announce the 2022 Medicare Part B rates, premium and deductible; the passages above are CMS’s account of what it took into account in setting them.

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8. What the Approval Did Not Do

• It was not a traditional approval. CDER’s report states that confirmatory trials “must be conducted to support traditional approval,” and the U.S. Food and Drug Administration’s notice says continued approval “may be contingent upon verification of clinical benefit in confirmatory trial(s).”
• It did not rest on a demonstrated clinical benefit. The basis the U.S. Food and Drug Administration states is a reduction in amyloid beta plaques, a surrogate endpoint (section 4).
• It was not described as a cure. None of the U.S. Food and Drug Administration documents read for this page calls the drug a cure; CDER describes it as a treatment that targets the disease process.
• It did not settle Medicare coverage. The U.S. Food and Drug Administration approves medicines for marketing; the 2021 CMS notice concerns how CMS set the 2022 Part B premium, not a coverage decision.
• It did not last. The U.S. Food and Drug Administration now lists the indication as a withdrawn accelerated approval (section 9).

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9. Dates and Legal Status as of October 18, 2026

• July 7, 2020: biologics license application 761178 first submitted.
• November 6, 2020: U.S. Food and Drug Administration advisory committee meeting on the application.
• June 7, 2021: accelerated approval “to treat Alzheimer’s disease.”
• July 19, 2021: the U.S. Department of Health and Human Services Advisory Council on Alzheimer’s Research, Care, and Services discusses the approval.
• November 17, 2021: CMS cites the drug among the factors in setting the 2022 Medicare Part B premium.
• February 29, 2024: the U.S. Food and Drug Administration publishes its determination of the product’s regulatory review period for a patent-term extension (89 FR 14869; Docket Nos. FDA-2022-E-0654 and FDA-2022-E-0655). Such a notice measures how long the product spent in testing and U.S. Food and Drug Administration review, which can be used to extend a patent; it is not a safety or effectiveness decision.
• November 1, 2024: the conversion–withdrawal date the U.S. Food and Drug Administration lists for the accelerated approval.

Status as of October 18, 2026: approval withdrawn. The U.S. Food and Drug Administration’s list “Withdrawn | Non-malignant Hematological, Neurological, and Other Disorder Indications Accelerated Approvals,” current as of February 25, 2026, shows aducanumab’s accelerated approval for “the treatment of alzheimer’s disease” (approved 6/7/2021) with a withdrawal date of 11/1/2024. The U.S. Food and Drug Administration explains that the list covers accelerated approvals whose postmarketing requirements “have been subsequently withdrawn, and are therefore, no longer U.S. Food and Drug Administration-approved,” and that withdrawn indications “are not listed until U.S. Food and Drug Administration publishes a Federal Register notice to that effect or updates product labeling.” The U.S. Food and Drug Administration documents read for this page do not state who initiated the withdrawal or why, so this page does not report a reason. A check of the Federal Register through October 18, 2026 found no other document on the product that changes this status.

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10. How It Fits Later U.S. Food and Drug Administration Alzheimer’s Actions

Two later anti-amyloid antibodies, and the end of aducanumab’s approval, are reported as follows:

• 2023. A second anti-amyloid antibody, lecanemab, received accelerated approval on January 6, 2023 and traditional approval on July 6, 2023; the U.S. Food and Drug Administration lists it among accelerated approvals with “verified clinical benefit.” See U.S. Food and Drug Administration Grants Lecanemab Full Approval for Early Alzheimer’s Disease (2023).
• 2024. A third, donanemab, was approved for early Alzheimer’s disease. See U.S. Food and Drug Administration Approves Donanemab for Early Alzheimer’s Disease (2024).
• 2024. Aducanumab’s accelerated approval is listed as withdrawn (November 1, 2024).

The two U.S. Food and Drug Administration lists side by side show the two ways an accelerated approval can end: converted to a traditional approval once confirmatory evidence verifies a clinical benefit (lecanemab), or withdrawn (aducanumab). Another withdrawn accelerated approval, for a medicine to reduce the risk of preterm birth, is reported on the 2023 preterm birth drug withdrawal page. Among the other 2021 drug actions, the JAK inhibitor boxed warnings and the removal of the statin pregnancy warning show the U.S. Food and Drug Administration changing the labeling of medicines already on the market.

Questions about any Alzheimer’s treatment belong with a clinician.

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11. Primary Documents

1. U.S. Food and Drug Administration. Novel Drug Approvals for 2021. Content current as of May 22, 2024 (entry 26, aducanumab-avwa, June 7, 2021) — fda.gov Novel Drug Approvals for 2021
2. U.S. Food and Drug Administration, Center for Drug Evaluation and Research. Advancing Health Through Innovation: New Drug Therapy Approvals 2021. Report (pp. 9, 12, 17–21 and Appendix A) — fda.gov CDER 2021 report (PDF)
3. U.S. Food and Drug Administration. Withdrawn | Non-malignant Hematological, Neurological, and Other Disorder Indications Accelerated Approvals. Content current as of February 25, 2026 — fda.gov withdrawn accelerated approvals list
4. U.S. Food and Drug Administration. Verified Clinical Benefit | Non-malignant Hematological, Neurological, and Other Disorder Indications. Content current as of November 19, 2024 (lecanemab entry) — fda.gov verified clinical benefit list
5. Food and Drug Administration, U.S. Department of Health and Human Services (2020). Peripheral and Central Nervous System Drugs Advisory Committee; Notice of Meeting; Establishment of a Public Docket; Request for Comments. Federal Register 85 FR 61013, September 29, 2020. Docket No. FDA-2018-N-0410 — FR Doc. 2020-21448
6. Department of Health and Human Services (2021). Advisory Council on Alzheimer’s Research, Care, and Services; Meeting. Federal Register 86 FR 34242, June 29, 2021 — FR Doc. 2021-13851
7. Centers for Medicare & Medicaid Services, U.S. Department of Health and Human Services (2021). Medicare Program; Medicare Part B Monthly Actuarial Rates, Premium Rates, and Annual Deductible Beginning January 1, 2022. Federal Register 86 FR 64205, November 17, 2021. CMS-8079-N — FR Doc. 2021-25050
8. Food and Drug Administration, U.S. Department of Health and Human Services (2024). Determination of Regulatory Review Period for Purposes of Patent Extension (aducanumab-avwa; title names the product). Federal Register 89 FR 14869, February 29, 2024. Docket Nos. FDA-2022-E-0654 and FDA-2022-E-0655 — FR Doc. 2024-04214

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Key Research Papers

1. Sevigny J, Chiao P, Bussière T, Weinreb PH, Williams L, Maier M, Dunstan R, Salloway S, et al. (2016). The antibody aducanumab reduces Aβ plaques in Alzheimer’s disease. Nature 537(7618):50-56 — PubMed PMID: 27582220
2. Budd Haeberlein S, Aisen PS, Barkhof F, Chalkias S, Chen T, Cohen S, Dent G, Hansson O, et al. (2022). Two Randomized Phase 3 Studies of Aducanumab in Early Alzheimer’s Disease. The Journal of Prevention of Alzheimer’s Disease 9(2):197-210 — PubMed PMID: 35542991
3. Mallinckrodt C, Tian Y, Aisen PS, Barkhof F, Cohen S, Dent G, Hansson O, Harrison K, et al. (2023). Investigating Partially Discordant Results in Phase 3 Studies of Aducanumab. The Journal of Prevention of Alzheimer’s Disease 10(2):171-177 — PubMed PMID: 36946443
4. Salloway S, Chalkias S, Barkhof F, Burkett P, Barakos J, Purcell D, Suhy J, Forrestal F, et al. (2022). Amyloid-Related Imaging Abnormalities in 2 Phase 3 Studies Evaluating Aducanumab in Patients With Early Alzheimer Disease. JAMA Neurology 79(1):13-21 — PubMed PMID: 34807243
5. Dunn B, Stein P, Cavazzoni P (2021). Approval of Aducanumab for Alzheimer Disease—The FDA’s Perspective. JAMA Internal Medicine 181(10):1276-1278 — PubMed PMID: 34254984
6. Alexander GC, Knopman DS, Emerson SS, Ovbiagele B, Kryscio RJ, Perlmutter JS, Kesselheim AS (2021). Revisiting FDA Approval of Aducanumab. The New England Journal of Medicine 385(9):769-771 — PubMed PMID: 34320282
7. Rabinovici GD (2021). Controversy and Progress in Alzheimer’s Disease — FDA Approval of Aducanumab. The New England Journal of Medicine 385(9):771-774 — PubMed PMID: 34320284
8. van Dyck CH, Swanson CJ, Aisen P, Bateman RJ, Chen C, Gee M, Kanekiyo M, Li D, et al. (2023). Lecanemab in Early Alzheimer’s Disease. The New England Journal of Medicine 388(1):9-21 — PubMed PMID: 36449413

The first paper reports the early study of the antibody’s effect on amyloid plaques. The next three report the two phase 3 trials, an analysis of why their results partly disagreed, and the brain-imaging changes (amyloid-related imaging abnormalities) recorded in those trials. The fifth sets out the approval from the point of view of U.S. Food and Drug Administration drug-center officials; the sixth and seventh are commentaries on the approval published in 2021. The last reports the phase 3 trial of lecanemab, a later anti-amyloid antibody.

PubMed Topic Searches

1. PubMed: aducanumab
2. PubMed: accelerated approval and surrogate endpoints
3. PubMed: anti-amyloid antibodies in Alzheimer’s disease

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Connections

• U.S. Food and Drug Administration Actions of 2021
• U.S. Food and Drug Administration and Regulation
• Alzheimer’s Disease
• Alzheimer’s Disease: History and Discovery
• Dementia
• Lecanemab Full Approval (2023)
• Donanemab Approval (2024)
• Preterm Birth Drug Withdrawal (2023)
• JAK Inhibitor Boxed Warnings (2021)
• Statin Pregnancy Warning Removed (2021)
• Varenicline Nitrosamine Recall and Limit (2021)

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