March 2, 2023
Biogen Japan Ltd.
Eisai Co., Ltd.

BIOGEN JAPAN AND EISAI PROVIDE UPDATE ON CO-PROMOTION OF
MULTIPLE SCLEROSIS TREATMENTS IN JAPAN
Biogen Japan Ltd. (Headquarters: Tokyo, President and Representative Director: Takatsugu Den,“Biogen Japan”) and Eisai Co., Ltd. (Headquarters: Tokyo, CEO: Haruo Naito, “Eisai”) announced
today the termination of the co-promotion agreement that has been in place since January 2018
for Biogen Japan's multiple sclerosis (MS) treatments TECFIDERA® (dimethyl fumarate),TYSABRI® (natalizumab, genetic recombinant) and AVONEX® (interferon beta 1a, geneticrecombinant) in Japan as of March 31, 2023.
The two companies have been jointly engaged in promotional activities for MS treatments inJapan. However, since a certain objective has been achieved regarding penetration of theproducts into the Japanese market, the two companies decided to terminate this co-promotionagreement. As a result, Biogen Japan will have full responsibility for all operations related to theproducts after a transition period between the two companies. Upon termination of this agreement,
Biogen will pay Eisai 31 million USD.
The termination of this co-promotion agreement does not impact any of the other agreements
between Biogen and Eisai.

Contacts
MEDIA CONTACT:MEDIA CONTACT:Biogen Japan Ltd.

Eisai Co., Ltd.

Public Relations & CSR Department

Public Relations Department

MOB: +81-(0)70-1501-4315

TEL: +81-(0)3-3817-5120

TEL: +81-(0)3-3275-1745

[Notes to editors]

1.

About Multiple Sclerosis Treatments TECFIDERA, TYSABRI and AVONEXTECFIDERA (dimethyl fumarate) is an orally-administered medicine for the treatment of relapsing forms ofmultiple sclerosis, including relapse-remitting multiple sclerosis, the most common type of multiple sclerosis.
TECFIDERA was approved in Japan for the prevention of relapse and for delaying the accumulation ofphysical disability in multiple sclerosis in December 2016, and was launched in February 2017. First
approved in 2013 in the United States, TECFIDERA has been approved in over 54 countries. TECFIDERA
is widely used in the United States and countries in Europe as a first-line treatment, and the number ofpatients who have been treated with TECFIDERA worldwide to date reached 250,000.
TYSABRI (natalizumab, genetic recombinant) is a humanized monoclonal anti-α4 integrin antibody and adisease modifying drug. TYSABRI was approved in Japan for the prevention of relapse and delaying theaccumulation of physical disability in multiple sclerosis in March 2014, and was launched in June of thesame year. TYSABRI has been approved in over 77 countries worldwide including the United States andcountries in Europe, and the number of patients who have been treated with TYSABRI worldwide reached
167,000.
AVONEX (interferon beta 1a, genetic recombinant) was approved in Japan for relapse prevention of multiple
sclerosis in July 2006, and was launched in November of the same year. In December 2013 a pen
formulation was approved and subsequently launched in June 2014.
2.

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 focused on its
purpose of serving humanity through science while advancing a healthier, more sustainable and equitableworld.
The company routinely posts information that may be important to investors on its website athttps://www.biogen.com/. Follow Biogen on social media – Twitter, LinkedIn, Facebook, YouTube.
Biogen Japan is a subsidiary of Biogen in the U.S. Biogen Japan, as the Japanese affiliate of one of theoldest independent biotechnology companies, started its operation in Japan in 2000. To learn more about
Biogen Japan, please visit https://www.biogen.co.jp/.
3.

About Eisai

Eisai’s Corporate Concept is “to give first thought to patients and people in the daily living domain, and toincrease the benefits that health care provides.” Under this Concept (also known as human health care (hhc)Concept), we aim to effectively achieve social good in the form of relieving anxiety over health and reducing
health disparities. With a global network of R&D facilities, manufacturing sites and marketing subsidiaries,
we strive to create and deliver innovative products to target diseases with high unmet medical needs, with aparticular 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), with working on various
activities together with global partners.
For more information about Eisai, please visit www.eisai.com (for global headquarters: Eisai Co., Ltd.), andconnect with us on Twitter @Eisai_SDGsBiogen Safe Harbor
This news release contains forward-looking statements, including statements made pursuant to the safe
harbor provisions of the Private Securities Litigation Reform Act of 1995, about Biogen Japan’s
promotional activities in Japan with respect to MS products; the anticipated benefits and potential of
Biogen’s termination of the co-promotion; collaboration arrangements with Eisai; the potential of Biogen’scommercial business and pipeline programs; and risks and uncertainties associated with drug
development and commercialization. These statements may be identified by words such as “aim,”“anticipate,” “believe,” “could,” “estimate,” “expect,” “forecast,” “intend,” “may,” “plan,” “possible,” “potential,”“will,” “would” and other words and terms of similar meaning. Drug development and commercialization
involve a high degree of risk, and only a small number of research and development programs result incommercialization of a product. Results in early-stage clinical studies may not be indicative of full results or
results from later stage or larger scale clinical studies and do not ensure regulatory approval. You should
not place undue reliance on these statements or the scientific 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 arise fromtransition of co-promotion to Biogen Japan; risks of unexpected costs or delays; the risk of otherunexpected hurdles; regulatory submissions may take longer or be more difficult to complete thanexpected; 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; failure to protect and enforce Biogen’s
data, intellectual property and other proprietary rights and uncertainties relating to intellectual property
claims and challenges; product liability claims; third party collaboration risks; and the direct and indirect
impacts of the ongoing COVID-19 pandemic on Biogen’s business, results of operations and financialcondition. The foregoing sets forth many, but not all, of the factors that could cause actual results to differ
from Biogen’s expectations in any forward-looking statement. Investors should consider this cautionary
statement as well as the risk factors identified in Biogen’s most recent annual or quarterly report and inother 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 not undertake any obligation to publicly update any forward-looking statements, whether as aresult of new information, future developments or otherwise.