United states securities and exchange commission

Table of Contents
NOTE REGARDING FORWARD-LOOKING STATEMENTS 
This report contains forward-looking statements that are being made pursuant to the provisions of the Private 
Securities Litigation Reform Act of 1995 (the Act) with the intention of obtaining the benefits of the “Safe Harbor” 
provisions of the Act. These forward-looking statements may be accompanied by such words as “aim,” “anticipate,” 
“believe,” “could,” “estimate,” “expect,” “forecast,” “intend,” “may,” “plan,” “potential,” “possible,” “will” and other 
words and terms of similar meaning. Reference is made in particular to forward-looking statements regarding:
•  the anticipated amount, timing and accounting of revenues, contingent payments, milestone, royalty and other 
payments under licensing, collaboration or acquisition agreements, tax positions and contingencies, 
collectability of receivables, pre-approval inventory, cost of sales, research and development costs, 
compensation and other selling, general and administrative expenses, amortization of intangible assets, foreign 
currency exchange risk, estimated fair value of assets and liabilities and impairment assessments;
•  expectations, plans and prospects relating to sales, pricing, growth and launch of our marketed and pipeline 
products;
•  our plans to invest in emerging growth areas such as pain, ophthalmology, neuropsychiatry and acute 
neurology;
•  the potential impact of increased product competition in the markets in which we compete;
•  patent terms, patent term extensions, patent office actions and expected availability and period of regulatory 
exclusivity;
•  the costs and timing of potential clinical trials, filings and approvals, and the potential therapeutic scope of the 
development and commercialization of our and our collaborators’ pipeline products;
•  the drivers for growing our business, including our plans and intent to commit resources relating to business 
development opportunities and research and development programs;
•  the anticipated benefits and the potential costs and expenses related to our current or future initiatives to 
streamline our operations and reallocate resources; 
•  our manufacturing capacity, use of third-party contract manufacturing organizations and plans and timing 
relating to the expansion of our manufacturing capabilities, including anticipated investments and activities in 
new manufacturing facilities;
•  the potential impact on our results of operations and liquidity of the United Kingdom's (U.K.) intent to 
voluntarily depart from the European Union (E.U.);
•  the impact of the continued uncertainty of the credit and economic conditions in certain countries in Europe 
and our collection of accounts receivable in such countries;
•  the potential impact of healthcare reform in the United States (U.S.) and measures being taken worldwide 
designed to reduce healthcare costs to constrain the overall level of government expenditures, including the 
impact of pricing actions and reduced reimbursement for our products;
•  the timing, outcome and impact of administrative, regulatory, legal and other proceedings related to our patents 
and other proprietary and intellectual property rights, tax audits, assessments and settlements, pricing matters, 
sales and promotional practices, product liability and other matters;
•  lease commitments, purchase obligations and the timing and satisfaction of other contractual obligations;
•  our ability to finance our operations and business initiatives and obtain funding for such activities;
•  the anticipated benefits, costs and tax treatment of the spin-off of our hemophilia business; and
•  the impact of new laws, including the Tax Cuts and Jobs Act of 2017, and accounting standards.
These forward-looking statements involve risks and uncertainties, including those that are described in Item 
1A. Risk Factors included in this report and elsewhere in this report that could cause actual results to differ 
materially from those reflected in such statements. You should not place undue reliance on these statements. 
Forward-looking statements speak only as of the date of this report. Except as required by law, we do not undertake 
any obligation to publicly update any forward-looking statements, whether as a result of new information, future 
developments or otherwise.

---

Table of Contents
NOTE REGARDING COMPANY AND PRODUCT REFERENCES
References in this report to:
•  “Biogen,” the “company,” “we,” “us” and “our” refer to Biogen Inc. and its consolidated subsidiaries;
•  “RITUXAN” refers to both RITUXAN (the trade name for rituximab in the U.S., Canada and Japan) and MabThera 
(the trade name for rituximab outside the U.S., Canada and Japan); and
•  "ELOCTATE" refers to both ELOCTATE (the trade name for Antihemophilic Factor (recombinant), Fc Fusion Protein 
in the U.S., Canada and Japan) and ELOCTA (the trade name for Antihemophilic Factor (recombinant), Fc Fusion 
Protein in the E.U.).
NOTE REGARDING TRADEMARKS
AVONEX®, PLEGRIDY®, RITUXAN®, RITUXAN HYCELA®, SPINRAZA®, TECFIDERA®, TYSABRI® and ZINBRYTA® 
are registered trademarks of Biogen. BENEPALI
TM
, FLIXABI
TM
, FUMADERM
TM 
and IMRALDI
TM 
are trademarks of Biogen. 
ALPROLIX®, ELOCTATE®, ENBREL®, FAMPYRA
TM
, GAZYVA®, HUMIRA®, OCREVUS®, REMICADE® and other 
trademarks referenced in this report are the property of their respective owners.

---

Table of Contents
1
PART I
Item 1.  
Business
Overview
Biogen is a global biopharmaceutical company focused on discovering, developing and delivering worldwide 
innovative therapies for people living with serious neurological and neurodegenerative diseases, including in our core 
growth areas of multiple sclerosis (MS) and neuroimmunology, Alzheimer’s disease (AD) and dementia, movement 
disorders and neuromuscular disorders, including spinal muscular atrophy (SMA) and amyotrophic lateral sclerosis 
(ALS). We also plan to invest in emerging growth areas such as pain, ophthalmology, neuropsychiatry and acute 
neurology. In addition, we are employing innovative technologies to discover potential treatments for rare and genetic 
disorders, including new ways of treating diseases through gene therapy in the previously mentioned areas. We also 
manufacture and commercialize biosimilars of advanced biologics.
Our marketed products include TECFIDERA, AVONEX, PLEGRIDY, TYSABRI, ZINBRYTA and FAMPYRA for the 
treatment of MS, SPINRAZA for the treatment of SMA and FUMADERM for the treatment of severe plaque psoriasis. 
We also have certain business and financial rights with respect to RITUXAN for the treatment of non-Hodgkin's 
lymphoma, chronic lymphocytic leukemia (CLL) and other conditions, GAZYVA for the treatment of CLL and follicular 
lymphoma, OCREVUS for the treatment of primary progressive MS and relapsing MS and other potential anti-CD20 
therapies under a collaboration agreement with Genentech, Inc. (Genentech), a wholly-owned member of the Roche 
Group. 
We support our drug discovery and development efforts through the commitment of significant resources to 
discovery, research and development programs and business development opportunities, particularly within our core 
and emerging growth areas. For nearly two decades we have led in the research and development of new therapies 
to treat MS, resulting in our leading portfolio of MS treatments. Now our research is focused on additional 
improvements in the treatment of MS, such as the development of next generation therapies for MS, with a goal to 
reverse or possibly repair damage caused by the disease. We are also applying our scientific expertise to solve 
some of the most challenging and complex diseases, including AD, progressive supranuclear palsy (PSP), a rare 
condition that affects movement, speech, vision and cognitive function, Parkinson's disease and ALS.
Our innovative drug development and commercialization activities are complemented by our biosimilar therapies 
that expand access to medicines and reduce the cost burden for healthcare systems. We are leveraging our 
manufacturing capabilities and know-how to develop, manufacture and market biosimilars through Samsung Bioepis, 
our joint venture with Samsung BioLogics Co. Ltd. (Samsung Biologics). Under our commercial agreement, we market 
and sell BENEPALI, an etanercept biosimilar referencing ENBREL, and FLIXABI, an infliximab biosimilar referencing 
REMICADE, in the E.U.

---