United states securities and exchange commission

Table of Contents
BIOGEN INC. AND SUBSIDIARIES
NOTES TO CONSOLIDATED FINANCIAL STATEMENTS — (Continued)
F- 55
beginning in mid-February 2009.
In July 2013 we negotiated an agreement in principle with AIFA's Price and Reimbursement Committee that 
would have resolved all of AIFA's claims relating to sales of TYSABRI in excess of the reimbursement limit for the 
periods from February 2009 through January 2013 for an aggregate repayment of EUR33.3 million. As a result of 
this agreement in principle, we recorded a liability and reduction to revenue of EUR15.4 million at June 30, 2013, 
which approximated 50% of the claim related to the period from mid-February 2009 through mid-February 2011. 
In June 2014 AIFA approved a resolution affirming that there is no reimbursement limit from and after February 
2013. As a result, we recognized $53.5 million of TYSABRI revenues related to the periods February 2013 through 
June 2014 that were previously deferred.
In the first quarter of 2017 we reached an agreement with AIFA's Price and Reimbursement Committee 
resolving all of AIFA's claims relating to sales of TYSABRI in excess of the reimbursement limit for prior periods. As a 
result, in the first quarter of 2017, we recognized EUR41.8 million (approximately $45.0 million) in revenues for 
sales that were previously deferred. These amounts were previously accrued for and included in the table above in 
Other as of December 31, 2016.
19.   Investments in Variable Interest Entities
Consolidated Variable Interest Entities
Our consolidated financial statements include the financial results of variable interest entities in which we are 
the primary beneficiary. The following are our significant variable interest entities.
Neurimmune
In November 2007 we entered into a collaboration and license agreement with Neurimmune Subone AG 
(Neurimmune) for the development and commercialization of antibodies for the treatment of AD. We are responsible 
for the development, manufacturing and commercialization of all collaboration products. This agreement is effective 
for the longer of the duration of certain patents relating to a licensed product, or 12 years from the first commercial 
sale of any product using such a licensed compound. Our anti-amyloid beta antibody, aducanumab, for the treatment 
of AD resulted from this collaboration. 
We consolidate the results of Neurimmune as we determined that we are the primary beneficiary of 
Neurimmune because we have the power through the collaboration to direct the activities that most significantly 
impact the entity’s economic performance and we are required to fund 100% of the research and development costs 
incurred in support of the collaboration. Under this agreement, we are also required to pay royalties on sales of any 
resulting commercial products and make payments upon the achievement of certain milestone events. 
In October 2017 we amended the terms of our collaboration and license agreement with Neurimmune. Under 
the amended agreement, we made a $150.0 million payment to Neurimmune in exchange for a 15% reduction in 
royalty rates payable on products developed under the agreement, including on potential commercial sales of 
aducanumab. Our royalty rates payable on products developed under the agreement, including on potential 
commercial sales of aducanumab, will now range from the high single digits to low teens. As we consolidate the 
results of Neurimmune, we recognized this payment as a charge to noncontrolling interest in the fourth quarter of 
2017 and treated it as a distribution. Under the amended agreement, we also have an option that will expire in April 
2018 to further reduce our royalty rates payable on products developed under the agreement, including on potential 
commercial sales of aducanumab, by an additional 5% in exchange for a $50.0 million payment to Neurimmune. 
Research and development costs for which we reimburse Neurimmune are reflected in research and 
development expense in our consolidated statements of income. During the years ending December 31, 2017, 2016 
and 2015 amounts reimbursed were immaterial.
In September 2015 we recognized a $60.0 million milestone payable to Neurimmune upon enrollment of the 
first patient in a Phase 3 trial for aducanumab. We recognized this payment as a charge to noncontrolling interest. 
Based upon our current development plans for aducanumab, we may pay Neurimmune up to $275.0 million in 
remaining milestone payments. Future milestone payments and royalties, if any, will be reflected in our consolidated 
statements of income as a charge to noncontrolling interest, net of tax when such milestones are achieved.

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Table of Contents
BIOGEN INC. AND SUBSIDIARIES
NOTES TO CONSOLIDATED FINANCIAL STATEMENTS — (Continued)
F- 56
The assets and liabilities of Neurimmune are not significant to our consolidated financial position or results of 
operations as it is a research and development organization. We have provided no financing to Neurimmune other 
than previously contractually required amounts.
Under the terms of our October 2017 collaboration agreement with Eisai for the joint development and 
commercialization of aducanumab, Eisai may elect to share in the benefit and cost associated with the royalty 
reductions discussed above. Eisai has elected to not share in the benefit and cost of the October 2017 royalty 
reduction. For additional information on our collaboration arrangement with Eisai, please read Note 20, Collaborative 
and Other Relationships, to these consolidated financial statements.
Unconsolidated Variable Interest Entities
We have relationships with other variable interest entities that we do not consolidate as we lack the power to 
direct the activities that significantly impact the economic success of these entities. These relationships include 
investments in certain biotechnology companies and research collaboration agreements. 
As of December 31, 2017 and 2016, the carrying value of our investments in biotechnology companies totaled 
$48.3 million and $47.4 million, respectively. Our maximum exposure to loss related to these variable interest 
entities is limited to the carrying value of our investments.
We have also entered into research collaboration agreements with certain variable interest entities where we 
are required to fund certain development activities. These development activities are included in research and 
development expense in our consolidated statements of income, as they are incurred. We have provided no financing 
to these variable interest entities other than previously contractually required amounts. 
20.    Collaborative and Other Relationships
In connection with our business strategy, we have entered into various collaboration agreements that provide 
us with rights to develop, produce and market products using certain know-how, technology and patent rights 
maintained by our collaborative partners. Terms of the various collaboration agreements may require us to make 
milestone payments upon the achievement of certain product research and development objectives and pay royalties 
on future sales, if any, of commercial products resulting from the collaboration.
Depending on the collaborative arrangement, we may record funding receivable or payable balances with our 
partners, based on the nature of the cost-sharing mechanism and activity within the collaboration. Our significant 
collaboration arrangements are discussed below.
Genentech (Roche Group)
We have certain business and financial rights with respect to RITUXAN for the treatment of non-Hodgkin's 
lymphoma, CLL and other conditions, GAZYVA for the treatment of CLL and follicular lymphoma, OCREVUS for the 
treatment of primary progressive MS (PPMS) and relapsing MS (RMS) and other potential anti-CD20 therapies under 
a collaboration agreement with Genentech, a wholly-owned member of the Roche Group. The Roche Group and its 
sub-licensees maintain sole responsibility for the development, manufacturing and commercialization of GAZYVA in 
the U.S. 
Our collaboration agreement will continue in effect until we mutually agree to terminate the collaboration, 
except that if we undergo a change in control, as defined in our collaboration agreement, Genentech has the right to 
present an offer to buy the rights to RITUXAN and we must either accept Genentech’s offer or purchase Genentech’s 
rights on the same terms as its offer. Genentech will also be deemed concurrently to have purchased our rights to 
any other anti-CD20 products in development in exchange for a royalty and our rights to GAZYVA in exchange for the 
compensation described in the table below. Our collaboration with Genentech was created through a contractual 
arrangement and not through a joint venture or other legal entity.
RITUXAN
Genentech is responsible for the worldwide manufacturing of RITUXAN. Development and commercialization 
rights and responsibilities under this collaboration are divided as follows:
U.S.
We share with Genentech co-exclusive rights to develop, commercialize and market RITUXAN in the U.S.

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