FDA Grants Traditional Approval for LEQEMBI® (lecanemab-irmb) for the Treatment of
Alzheimer’s Disease

The first and only approved treatment shown to reduce the rate of disease progression and to slow
cognitive and functional decline in adults with Alzheimer’s disease

The Centers for Medicare & Medicaid Services (CMS) announced broader Medicare coverage of
LEQEMBITOKYO and CAMBRIDGE, Mass., July 6, 2023 – Eisai Co., Ltd. (Headquarters: Tokyo, CEO: Haruo
Naito, “Eisai”) and Biogen Inc. (Nasdaq: BIIB, Corporate headquarters: Cambridge, Massachusetts,
CEO: Christopher A. Viehbacher, “Biogen”) announced today that the U.S. Food and Drug
Administration (FDA) has approved the supplemental Biologics License Application (sBLA) supporting
the traditional approval of LEQEMBI® (lecanemab-irmb) 100 mg/mL injection for intravenous use,making LEQEMBI the first and only approved treatment shown to reduce the rate of disease progression
and to slow cognitive and functional decline in adults with Alzheimer’s disease (AD). LEQEMBI
demonstrated clinically meaningful slowing of cognitive and functional decline in a patient group
generalizable to U.S. Medicare beneficiaries, which included a mix of racial and ethnic groups, patientswith common comorbid conditions, concomitant medications and patients with mild cognitive
impairment (MCI) due to AD or mild AD. Treatment with LEQEMBI should be initiated in patients with
MCI or mild dementia stage of disease, (collectively referred to as early AD) the population in which
treatment was initiated in clinical trials.
LEQEMBI’s traditional approval is based on Phase 3 data from Eisai’s large, global Clarity AD clinical
trial, in which LEQEMBI met its primary endpoint and all key secondary endpoints with statisticallysignificant results and confirmed the clinical benefit of LEQEMBI. The primary endpoint was the global
cognitive and functional scale, Clinical Dementia Rating Sum of Boxes (CDR-SB). LEQEMBI treatment
reduced clinical decline on CDR-SB by 27% at 18 months compared to placebo. Additionally, thesecondary endpoint of AD Cooperative Study-Activities of Daily Living Scale for Mild Cognitive
Impairment (ADCS MCI-ADL), as measured by people caring for patients with AD, noted a statisticallysignificant benefit of 37%. This measures the ability of patients to function independently, including
being able to dress, feed themselves and participate in community activities. Full results of the Clarity
AD study were presented at the Clinical Trials on Alzheimer's Disease (CTAD) 2022 conference andsimultaneously published in the peer-reviewed medical journal The New England Journal of Medicine
on November 29, 2022.
Importantly, following FDA’s traditional approval of LEQEMBI, CMS confirmed that broader coverageof LEQEMBI is now available and released more details on the registry, including the easy-to-use datasubmission process. The CMS-facilitated registry is now available for healthcare professionals to submit
required patient data to CMS. Eisai is pleased that Medicare will cover this important therapy for
appropriate patients. This will facilitate reimbursement for and access to LEQEMBI across a broad
range of healthcare settings in the United States.
“Today, the FDA approved LEQEMBI under the traditional approval pathway, making LEQEMBI thefirst and only approved anti-amyloid Alzheimer's disease treatment shown to reduce the rate of diseaseprogression and to slow cognitive impairment in the early and mild dementia stages of the disease. As
a research and development-focused company based on our hhc (human health care) concept, we areproud that the results of Eisai's AD research over the past 40 years have been recognized and delivered
to people living with this disease in the United States,” said Haruo Naito, Chief Executive Officer at Eisai.
“Alzheimer’s disease is a progressive, fatal disease that greatly impacts not only the people living withit, but also their loved ones, care partners and society. We continue to work to create broad and simple
access to LEQEMBI for patients and to support diagnosis and treatment at the early stage of the disease.

1Eisai will diligently work to educate physicians on the safe and appropriate use of LEQEMBI to maximize
its benefit to people living with early AD and their families.”“Today marks a breakthrough in the treatment of Alzheimer’s disease, and we are proud to be at theforefront of ushering in a new era of advances for a disease that was previously considered untreatable.
We would like to express our sincere appreciation to those who have worked tirelessly to find atreatment for this unrelenting disease, without whom this progress would not be possible,” said
Christopher A. Viehbacher, President and Chief Executive Officer of Biogen. "Our focus is now on thepath forward, working alongside Eisai with the goal of making LEQEMBI accessible to eligible patientsas soon as possible.”
LEQEMBI is a humanized immunoglobulin gamma 1 (IgG1) monoclonal antibody directed against
aggregated soluble (protofibril*) and insoluble forms of amyloid beta (Aβ). Critically, LEQEMBI targets
and clears the most neurotoxic form of Aβ that continuously accumulates as well as removes theexisting plaques to treat this progressive, chronic disease. In June 2023, the FDA’s Peripheral andCentral Nervous System Drugs (PCNS) advisory committee voted unanimously that the data from
Eisai’s Clarity AD clinical trial confirmed the clinical benefit of LEQEMBI for the treatment of AD.
Committee members also confirmed the overall risk-benefit of LEQEMBI. On January 6, 2023,
LEQEMBI was approved by the FDA under the accelerated approval pathway.
Eisai has developed and deployed Understanding ARIA™, a multi-faceted educational initiative tofurther advance understanding in the AD healthcare community of the real-world management andmonitoring of amyloid-related imaging abnormalities (ARIA). In collaboration with experts in the field of
medical imaging as well as major professional societies, Understanding ARIA™ offers resources andprograms that include peer-to-peer education, individual and group educational sessions and subjectmatter-expert evaluation of historical case studies.
Eisai is committed to ensuring that appropriate patients have access to LEQEMBI and has establisheda Patient Assistance Program to provide LEQEMBI at no cost, for eligible uninsured and underinsured
patients, including Medicare beneficiaries, who meet financial need and other program criteria.
Additionally, Eisai offers patient support for improving access through LEQEMBI Patient Navigators,
who will provide information about accessing LEQEMBI, help patients and their families understandtheir insurance coverage and options, and identify financial support programs for eligible patients.
People in the U.S. can learn more about these services by visiting LEQEMBI.com, calling 1-833-4LEQEMBI (1-833-453-7362), Monday-Friday, 8 a.m. to 8 p.m. Eastern Time or faxing an enrollment
form to 1-833-770-7017.
Eisai serves as the lead of LEQEMBI development and regulatory submissions globally with both Eisai
and Biogen co-commercializing and co-promoting the product and Eisai having final decision-making
authority.
*Protofibrils are large Aβ aggregated soluble species of 75-5000 Kd.2,3.4

INDICATIONLEQEMBI is indicated for the treatment of Alzheimer’s disease. Treatment with LEQEMBI should beinitiated in patients with mild cognitive impairment or mild dementia stage of disease, the population inwhich treatment was initiated in clinical trials.

2

IMPORTANT SAFETY INFORMATIONWARNING: AMYLOID RELATED IMAGING ABNORMALITIES (ARIA)• Monoclonal antibodies directed against aggregated forms of amyloid beta, including LEQEMBI,
can cause amyloid related imaging abnormalities (ARIA), characterized as ARIA with edema(ARIA-E) and ARIA with hemosiderin deposition (ARIA-H). Incidence and timing of ARIA vary
among treatments. ARIA usually occurs early in treatment and is usually asymptomatic,
although serious and life-threatening events rarely can occur. Serious intracerebral
hemorrhages>1 cm, some of which have been fatal, have been observed in patients treatedwith this class of medications.
o Apolipoprotein E ε4 (ApoE ε4) Homozygotes: Patients who are ApoE ε4homozygotes (approximately 15% of Alzheimer’s disease patients) treated with thisclass of medications, including LEQEMBI, have a higher incidence of ARIA, including
symptomatic, serious, and severe radiographic ARIA, compared to heterozygotes
and noncarriers. Testing for ApoE ε4 status should be performed prior to initiation oftreatment to inform the risk of developing ARIA. Prior to testing, prescribers should
discuss with patients the risk of ARIA across genotypes and the implications ofgenetic testing results. Prescribers should inform patients that if genotype testing is
not performed they can still be treated with LEQEMBI; however, it cannot be
determined if they are ApoE ε4 homozygotes and at higher risk for ARIA.
• Consider the benefit of LEQEMBI for the treatment of Alzheimer’s disease and potential risk ofserious adverse events associated with ARIA when deciding to initiate treatment with
LEQEMBICONTRAINDICATIONLEQEMBI is contraindicated in patients with serious hypersensitivity to lecanemab-irmb or to any of theexcipients of LEQEMBI. Reactions have included angioedema and anaphylaxis.
WARNINGS AND PRECAUTIONSAMYLOID RELATED IMAGING ABNORMALITIES• LEQEMBI can cause ARIA-E and ARIA-H. ARIA-E can be observed on MRI as brain edema or sulcal
effusions, and ARIA-H as microhemorrhage and superficial siderosis. ARIA can occur spontaneously
in patients with Alzheimer’s disease. ARIA-H associated with monoclonal antibodies directed against
aggregated forms of beta amyloid generally occurs in association with an occurrence of ARIA-E.
ARIA-H and ARIA-E can occur together.
• ARIA usually occurs early in treatment and is usually asymptomatic, although serious and lifethreatening events, including seizure and status epilepticus, rarely can occur. Reported symptoms
associated with ARIA may include headache, confusion, visual changes, dizziness, nausea, and gaitdifficulty. Focal neurologic deficits may also occur. Symptoms associated with ARIA usually resolve
over time.
ARIA Monitoring and Dose Management Guidelines• Obtain recent baseline brain magnetic resonance imaging (MRI) prior to initiating treatment with
LEQEMBI. Obtain an MRI prior to the 5th, 7th and 14th infusions.
• Recommendations for dosing in patients with ARIA-E and ARIA-H depend on clinical symptoms andradiographic severity. Depending on ARIA severity, use clinical judgment in considering whether tocontinue dosing, temporarily discontinue treatment, or permanently discontinue LEQEMBI.
• Enhanced clinical vigilance for ARIA is recommended during the first 14 weeks of treatment with
LEQEMBI. If a patient experiences symptoms suggestive of ARIA, clinical evaluation should be
performed, including MRI if indicated. If ARIA is observed on MRI, careful clinical evaluation shouldbe performed prior to continuing treatment.
• There is no experience in patients who continued dosing through symptomatic ARIA-E or throughasymptomatic, but radiographically severe, ARIA-E. There is limited experience in patients who
continued dosing through asymptomatic but radiographically mild to moderate ARIA-E. There arelimited data in dosing patients who experienced recurrent ARIA-E.

3

Incidence of ARIA
• In Study 2, symptomatic ARIA occurred in 3% (29/898) of LEQEMBI-treated patients. Serious
symptoms associated with ARIA were reported in 0.7% (6/898) of patients treated with LEQEMBI.
Clinical symptoms associated with ARIA resolved in 79% (23/29) of patients during the period of
observation.
• Including asymptomatic radiographic events, ARIA was observed in LEQEMBI: 21% (191/898);
placebo: 9% (84/897). ARIA-E was observed in LEQEMBI: 13% (113/898) placebo: 2% (15/897).
ARIA-H was observed in LEQEMBI: 17% (152/898); placebo: 9% (80/897). There was no increase
in isolated ARIA-H for LEQEMBI vs placebo.
ApoE ε4 Carrier Status and Risk of ARIA
• In Study 2, 16% (141/898) of patients in the LEQEMBI arm were ApoE ε4 homozygotes, 53%(479/898) were heterozygotes, and 31% (278/898) were noncarriers.
• The incidence of ARIA was higher in ApoE ε4 homozygotes (LEQEMBI: 45%; placebo: 22%) thanin heterozygotes (LEQEMBI: 19%; placebo: 9%) and noncarriers (LEQEMBI: 13%; placebo: 4%).
Among patients treated with LEQEMBI symptomatic ARIA-E occurred in 9% of ApoE ε4homozygotes compared with 2% of heterozygotes and 1% noncarriers. Serious events of ARIA
occurred in 3% of ApoE ε4 homozygotes, and approximately 1% of heterozygotes and noncarriers.
• The recommendations on management of ARIA do not differ between ApoE ε4 carriers andnoncarriers.
Radiographic Findings• The majority of ARIA-E radiographic events occurred early in treatment (within the first 7 doses),although ARIA can occur at any time and patients can have more than 1 episode. The maximum
radiographic severity of ARIA-E in patients treated with LEQEMBI was mild in 4% (37/898), moderate
in 7% (66/898), and severe in 1% (9/898). Resolution on MRI occurred in 52% of ARIA-E patientsby 12 weeks, 81% by 17 weeks, and 100% overall after detection. The maximum radiographic
severity of ARIA-H microhemorrhage in LEQEMBI-treated patients was mild in 9% (79/898),
moderate in 2% (19/898), and severe in 3% (28/898) of patients; superficial siderosis was mild in
4% (38/898), moderate in 1% (8/898), and severe in 0.4% (4/898). Among LEQEMBI-treatedpatients, the rate of severe radiographic ARIA-E was highest in ApoE ε4 homozygotes 5% (7/141),
compared to heterozygotes 0.4% (2/479) or noncarriers 0% (0/278). Among LEQEMBI-treatedpatients, the rate of severe radiographic ARIA H was highest in ApoE ε4 homozygotes 13.5%(19/141), compared to heterozygotes 2.1% (10/479) or noncarriers 1.1% (3/278).
Intracerebral Hemorrhage• Intracerebral hemorrhage >1 cm in diameter was reported in 0.7% (6/898) of patients in Study 2 after
treatment with LEQEMBI compared to 0.1% (1/897) on placebo. Fatal events of intracerebral
hemorrhage in patients taking LEQEMBI have been reported.
Concomitant Antithrombotic Medication:• In Study 2, baseline use of antithrombotic medication (aspirin, other antiplatelets, or
anticoagulants) was allowed if the patient was on a stable dose. The majority of exposures toantithrombotic medications were to aspirin. Antithrombotic medications did not increase the riskof ARIA with LEQEMBI. The incidence of intracerebral hemorrhage was 0.9% (3/328 patients)
in patients taking LEQEMBI with a concomitant antithrombotic medication at the time of theevent compared to 0.6% (3/545 patients) in those who did not receive an antithrombotic.
Patients taking LEQEMBI with an anticoagulant alone or combined with an antiplatelet
medication or aspirin had an incidence of intracerebral hemorrhage of 2.5% (2/79 patients)
compared to none in patients who received placebo.
• Because intracerebral hemorrhages >1 cm in diameter have been observed in patients taking
LEQEMBI, additional caution should be exercised when considering the administration of
anticoagulants or a thrombolytic agent (e.g., tissue plasminogen activator) to a patient alreadybeing treated with LEQEMBI.

4Other Risk Factors for Intracerebral Hemorrhage:• Patients were excluded from enrollment in Study 2 for findings on neuroimaging that indicatedan increased risk for intracerebral hemorrhage. These included findings suggestive of cerebral
amyloid angiopathy (prior cerebral hemorrhage >1 cm in greatest diameter, >4
microhemorrhages, superficial siderosis, vasogenic edema) or other lesions (aneurysm,
vascular malformation) that could potentially increase the risk of intracerebral hemorrhage. The
presence of an ApoE ε4 allele is also associated with cerebral amyloid angiopathy, which has
an increased risk for intracerebral hemorrhage. Caution should be exercised when considering
the use of LEQEMBI in patients with factors that indicate an increased risk for intracerebral
hemorrhage and in particular for patients who need to be on anticoagulant therapy.
HYPERSENSITIVITY REACTIONSHypersensitivity reactions, including angioedema, bronchospasm, and anaphylaxis, have occurred in
LEQEMBI-treated patients. Promptly discontinue the infusion upon the first observation of any signs or
symptoms consistent with a hypersensitivity reaction, and initiate appropriate therapy.
INFUSION-RELATED REACTIONS• In Study 2, infusion-related reactions were observed in LEQEMBI: 26% (237/898); placebo: 7%(66/897), and the majority of cases in LEQEMBI-treated patients (75%, 178/237) occurred with thefirst infusion. Infusion-related reactions were mostly mild (69%) or moderate (28%) in severity.
Infusion-related reactions resulted in discontinuations in 1% (12/898) of LEQEMBI-treated patients.
Symptoms of infusion-related reactions included fever and flu-like symptoms (chills, generalized
aches, feeling shaky, and joint pain), nausea, vomiting, hypotension, hypertension, and oxygen
desaturation.
• In the event of an infusion-related reaction, the infusion rate may be reduced, or the infusion may bediscontinued, and appropriate therapy initiated as clinically indicated. Prophylactic treatment withantihistamines, acetaminophen, nonsteroidal anti-inflammatory drugs, or corticosteroids prior to
future infusions may be considered.
ADVERSE REACTIONS• In Study 2, the most common adverse reactions leading to discontinuation of LEQEMBI was ARIAH microhemorrhages that led to discontinuation in 2% (15/898) of patients treated with LEQEMBI
compared to <1% (1/897) of patients on placebo.
• In Study 2, the most common adverse reactions reported in ≥5% of patients treated with LEQEMBI(N=898) and ≥2% higher than placebo (N=897) were infusion-related reactions (LEQEMBI: 26%;
placebo: 7%), ARIA-H (LEQEMBI: 14%; placebo: 8%), ARIA-E (LEQEMBI: 13%; placebo: 2%),
headache (LEQEMBI: 11%; placebo: 8%), superficial siderosis of central nervous system(LEQEMBI: 6%; placebo: 3%), rash (LEQEMBI: 6%; placebo: 4%), and nausea/vomiting (LEQEMBI:
6%; placebo: 4%).
Please see full Prescribing Information for LEQEMBI, including Boxed WARNING.

5

Media Contacts:
Eisai Co., Ltd.
Public Relations Department
TEL: +81 (0)3-3817-5120

Biogen Inc.
Jack Cox+ 1 781-464-3260
public.affairs@biogen.com

Eisai Inc. (U.S.)
Libby Holman+ 1-201-753-1945
Libby_Holman@eisai.com
Eisai Europe, Ltd.
(UK, Europe, Australia, New Zealand and Russia)
EMEA Communications Department+44 (0) 786 601 1272
EMEA-comms@eisai.net

Investor Contacts:
Biogen Inc.
Chuck Triano+ 1-781-464-2442
IR@biogen.com

Eisai Co., Ltd.
Investor Relations Department
TEL: +81 (0) 3-3817-5122
Notes to Editors

1. About LEQEMBI® (lecanemab-irmb)
LEQEMBI® (lecanemab-irmb) is the result of a strategic research alliance between Eisai and BioArctic.
LEQEMBI is a humanized immunoglobulin gamma 1 (IgG1) monoclonal antibody directed against
aggregated soluble (protofibril) and insoluble forms of amyloid-beta (Aβ). LEQEMBI is an amyloid betadirected antibody indicated as a disease-modifying treatment for Alzheimer’s disease (AD) in the U.S.
The U.S. Food and Drug Administration (FDA) granted LEQEMBI accelerated approval on January 6,
2023, and Traditional Approval on July 6, 2023. Treatment with LEQEMBI should be initiated in patientswith mild cognitive impairment or mild dementia stage of disease, the population in which treatment
was initiated in clinical trials. There are no safety or effectiveness data on initiating treatment at earlier
or later stages of the disease than were studied.
Eisai has also submitted applications for approval of lecanemab in Japan, EU, China, Canada, GreatBritain and South Korea. In Japan and China, the applications have been designated for priority review,
and in Great Britain, lecanemab has been designated for the Innovative Licensing and Access Pathway(ILAP), which aims to reduce the time to market for innovative medicines.
Eisai has completed a lecanemab subcutaneous bioavailability study, and subcutaneous dosing iscurrently being evaluated in the Clarity AD (Study 301) open-label extension (OLE). A maintenancedosing regimen has been evaluated as part of Study 201 as well as the Clarity AD (Study 301) OLE.
Separate supplemental Biologics License Applications for subcutaneous dosing and a maintenancedosing regimen will be submitted to the FDA at the end of Eisai's fiscal year.
Since July 2020 the Phase 3 clinical study (AHEAD 3-45) for individuals with preclinical AD, meaning
they are clinically normal and have intermediate or elevated levels of amyloid in their brains, is ongoing.
AHEAD 3-45 is conducted as a public-private partnership between the Alzheimer's Clinical Trial
Consortium that provides the infrastructure for academic clinical trials in AD and related dementias in
the U.S, funded by the National Institute on Aging, part of the National Institutes of Health, Eisai and
Biogen.
Since January 2022, the Tau NexGen clinical study for Dominantly Inherited AD (DIAD), that is
conducted by Dominantly Inherited Alzheimer Network Trials Unit (DIAN-TU), led by Washington
University School of Medicine in St. Louis, is ongoing.

62. About the Collaboration between Eisai and Biogen for AD
Eisai and Biogen have been collaborating on the joint development and commercialization of AD
treatments since 2014. Eisai serves as the lead of LEQEMBI development and regulatory submissions
globally with both companies co-commercializing and co-promoting the product and Eisai having final
decision-making authority.
3. About the Collaboration between Eisai and BioArctic for AD
Since 2005, Eisai and BioArctic have had a long-term collaboration regarding the development andcommercialization of AD treatments. Eisai obtained the global rights to study, develop, manufacture
and market LEQEMBI for the treatment of AD pursuant to an agreement with BioArctic in December
2007. The development and commercialization agreement on the antibody LEQEMBI back-up was
signed in May 2015.
4. About Eisai Co., Ltd.
Eisai's Corporate Concept is "to give first thought to patients and people in the daily living domain, andto increase the benefits that health care provides." Under this Concept (also known as human healthcare (hhc) Concept), we aim to effectively achieve social good in the form of relieving anxiety overhealth and reducing health disparities. With a global network of R&D facilities, manufacturing sites andmarketing subsidiaries, we strive to create and deliver innovative products to target diseases with highunmet medical needs, with a particular focus in our strategic areas of Neurology and Oncology.
In addition, we demonstrate our commitment to the elimination of neglected tropical diseases (NTDs),
which is a target (3.3) of the United Nations Sustainable Development Goals (SDGs), by working on
various activities together with global partners.
For more information about Eisai, please visit www.eisai.com (for global headquarters: Eisai Co., Ltd.),
and connect with us on Twitter, LinkedIn and Facebook.
5. About Biogen
Founded in 1978, Biogen is a leading global biotechnology company that has pioneered multiple
breakthrough innovations including a broad portfolio of medicines to treat multiple sclerosis, the first
approved treatment for spinal muscular atrophy, and two co-developed treatments to address a defining
pathology of Alzheimer’s disease. Biogen is advancing a pipeline of potential novel therapies acrossneurology, neuropsychiatry, specialized immunology and rare diseases and remains acutely focusedon its purpose of serving humanity through science while advancing a healthier, more sustainable andequitable world.
The company routinely posts information that may be important to investors on its website
at www.biogen.com. Follow Biogen on social media – Twitter, LinkedIn, Facebook, YouTube.
Biogen Safe Harbor
This news release contains forward-looking statements, including statements made pursuant to thesafe harbor provisions of the Private Securities Litigation Reform Act of 1995, about the potential clinicaleffects of lecanemab; the potential benefits, safety and efficacy of lecanemab; potential regulatory
discussions, submissions and approvals and the timing thereof; the treatment of Alzheimer's disease;
the anticipated benefits and potential of Biogen's collaboration arrangements with Eisai; the potential of
Biogen's commercial business and pipeline programs, including lecanemab; and risks and uncertainties
associated with drug development and commercialization. These statements may be identified bywords such as "aim," "anticipate," "believe," "could," "estimate," "expect," "forecast," "intend," "may,""plan," "possible," "potential," "will," "would" and other words and terms of similar meaning. Drugdevelopment and commercialization involve a high degree of risk, and only a small number of researchand development programs result in commercialization of a product. Results in early-stage clinicalstudies may not be indicative of full results or results from later stage or larger scale clinical studies anddo not ensure regulatory approval. You should not place undue reliance on these statements or thescientific data presented.
These statements involve risks and uncertainties that could cause actual results to differ materially fromthose reflected in such statements, including without limitation unexpected concerns that may arise7

from additional data, analysis or results obtained during clinical studies, including the Clarity AD clinical
trial and AHEAD 3-45 study; the occurrence of adverse safety events; risks of unexpected costs ordelays; the risk of other unexpected hurdles; regulatory submissions may take longer or be more difficult
to complete than expected; regulatory authorities may require additional information or further studies,or may fail or refuse to approve or may delay approval of Biogen's drug candidates, including
lecanemab; actual timing and content of submissions to and decisions made by the regulatory
authorities regarding lecanemab; uncertainty of success in the development and potentialcommercialization of lecanemab; failure to protect and enforce Biogen's data, intellectual property andother proprietary rights and uncertainties relating to intellectual property claims and challenges; productliability claims; third party collaboration risks; and the direct and indirect impacts of the ongoing COVID19 pandemic on Biogen's business, results of operations and financial condition. The foregoing sets
forth many, but not all, of the factors that could cause actual results to differ from Biogen's expectationsin any forward-looking statement. Investors should consider this cautionary statement as well as therisk factors identified in Biogen's most recent annual or quarterly report and in other reports Biogen has
filed with the U.S. Securities and Exchange Commission. These statements are based on Biogen's
current beliefs and expectations and speak only as of the date of this news release. Biogen does notundertake any obligation to publicly update any forward-looking statements, whether as a result of new
information, future developments or otherwise.

References
1. The Centers for Medicare and Medicaid Fact Sheet: CMS announces new details of plan tocover new Alzheimer’s drugs. CMS announces new details of plan to cover new Alzheimer’s
drugs | CMS. Accessed June 26, 2023.
2. https://www.alzforum.org/news/conference-coverage/lecanemab-sweeps-toxic-av-protofibrilscatches-eyes-trialists
3. Sehlin D, Englund H, Simu B, Karlsson M, Ingelsson M, Nikolajeff F, Lannfelt L, Pettersson
FE. Large aggregates are the major soluble Aβ species in AD brain fractionated with density
gradient ultracentrifugation. PLoS One. 2012;7(2):e32014.
https://doi.org/10.1371/journal.pone.0032014 Epub 2012 Feb 15. PMID: 22355408; PMCID:
PMC3280222.
4. Söderberg, L., Johannesson, M., Nygren, P. et al. Lecanemab, Aducanumab, andGantenerumab — Binding Profiles to Different Forms of Amyloid-Beta Might Explain Efficacy
and Side Effects in Clinical Trials for Alzheimer’s Disease. Neurotherapeutics. 2023;20:195206. https://doi.org/10.1007/s13311-022-01308-6

8