United states securities and exchange commission

Table of Contents
BIOGEN INC. AND SUBSIDIARIES
NOTES TO CONSOLIDATED FINANCIAL STATEMENTS — (Continued)
F- 63
A summary of activity related to the Eisai Collaboration Agreement is as follows:
 
For the Years Ended December 31,
(In millions)
2017
2016
2015
Total development expense incurred by the collaboration in
development of BAN2401 and E2609
$
146.2
$
95.1 $
84.1
Biogen's share of BAN2401 and E2609 development expense
reflected in our consolidated statements of income, excluding
upfront and milestone payments
$
74.3
$
50.5 $
40.4
During the fourth quarter of 2016 we recognized a $50.0 million milestone payment related to the initiation of 
a Phase 3 trial for E2609, which is included in research and development expense in our consolidated statements of 
income. We could pay Eisai up to an additional $625.0 million under the Eisai Collaboration Agreement based on the 
future achievement of certain development, regulatory and commercial milestones.
Aducanumab Collaboration Agreement
Under the Aducanumab Collaboration Agreement, we will continue to lead the ongoing Phase 3 development of 
aducanumab and will remain responsible for 100% of development costs for aducanumab incurred in support of this 
agreement until April 2018. Eisai will then reimburse us for 15% of aducanumab development expenses for the 
period April 2018 through December 2018, and 45% thereafter. Upon commercialization, both companies will co-
promote aducanumab with a region-based profit split. We will receive a 55% share of the potential profits (losses) in 
the U.S., a 68.5% share of the potential profits (losses) in the E.U. and a 20% share of the potential profits (losses) 
in Japan and Asia, excluding China and South Korea. The companies will continue to share equally in the potential 
profits (losses) in rest of world markets. 
We and Eisai also agreed to co-promote AVONEX, TYSABRI and TECFIDERA in Japan in certain settings and 
Eisai will distribute AVONEX, TYSABRI, TECFIDERA and PLEGRIDY in India and other Asia-Pacific markets, excluding 
China.  
During the year ended December 31, 2017, $263.4 million was reflected in research and development expense 
in our consolidated statements of income related to the advancement of our aducanumab program.
Anti-Tau Option
Eisai may exercise the Anti-Tau Option after completion of the Phase 1 clinical trial of such anti-tau monoclonal 
antibody. If Eisai exercises its Anti-Tau Option, we will receive an upfront payment from Eisai and will be entitled to 
additional development and commercial milestone payments.
Bristol-Myers Squibb Company
In June 2017 we completed an exclusive license agreement with Bristol-Myers Squibb Company (BMS) for 
BIIB092 (formerly known as BMS-986168), a Phase 2-ready experimental medicine with potential in AD and PSP. 
BIIB092 is an antibody targeting tau, the protein that forms the deposits, or tangles, in the brain associated with AD 
and other neurodegenerative tauopathies such as PSP. 
Under this agreement, we received worldwide rights to BIIB092 and are responsible for the full development 
and global commercialization of BIIB092 in AD and PSP. 
Upon entering into this agreement, we made an upfront payment of $300.0 million to BMS and we may pay 
BMS up to $410.0 million in additional milestone payments, and potential royalties. We also assumed all remaining 
obligations to the former shareholders of iPierian, Inc. (iPierian) related to BMS’s acquisition of iPierian in 2014. In 
June 2017 we recognized a $60.0 million developmental milestone payable to the former shareholders of iPierian 
upon dosing of the first patient in the Phase 2 PSP study for BIIB092 and we may pay the former shareholders of 
iPierian up to $490.0 million in remaining milestone payments, and potential royalties. 
Both the $300.0 million upfront payment and the $60.0 million developmental milestone payment were 
recognized as research and development expense in our consolidated statements of income for the year ended 
December 31, 2017. 

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Table of Contents
BIOGEN INC. AND SUBSIDIARIES
NOTES TO CONSOLIDATED FINANCIAL STATEMENTS — (Continued)
F- 64
Alkermes
In November 2017 we entered into an exclusive license and collaboration agreement with Alkermes Pharma 
Ireland Limited, a subsidiary of Alkermes plc (Alkermes), for BIIB098 (formerly known as ALKS 8700), an oral 
monomethyl fumarate prodrug in Phase 3 development for the treatment of relapsing forms of MS. 
Under this agreement, we received an exclusive, worldwide license to develop and commercialize BIIB098 and 
will pay Alkermes a mid-teens percentage royalty on potential worldwide net sales of BIIB098. Royalties payable on 
net sales of BIIB098 are subject to tiered minimum payment requirements for a period of five years following FDA 
approval. Alkermes is eligible to receive royalties in the mid-single digits to low-teen percentages of annual net sales 
upon successful development and commercialization of new product candidates other than BIIB098. Alkermes will 
maintain responsibility for regulatory interactions with the FDA through the potential approval of the NDA for BIIB098 
for the treatment of MS. 
Upon entering into this agreement, we made a $28.0 million upfront payment to Alkermes representing our 
share of BIIB098 development costs already incurred in 2017. Beginning in 2018 we are responsible for all 
development expenses related to BIIB098. In December 2017 we also recognized a $50.0 million expense, which is 
expected to be paid to Alkermes in early 2018, enabling the continuation of the agreement to develop BIIB098. Both 
the $28.0 million upfront payment and $50.0 million continuation payment were recognized as research and 
development expense in our consolidated financial statements for the year ended December 31, 2017. 
We may also pay Alkermes up to approximately $150.0 million in additional future milestone payments upon 
certain regulatory achievements related to BIIB098 under this collaboration. For the year ended December 31, 2017, 
we recorded $80.3 million in research and development expense in our consolidated statements of income related 
to this collaboration.
In connection with the license and collaboration agreement, we may also enter into a supply agreement with 
Alkermes for the commercial supply of BIIB098 and other products developed under the license and collaboration 
agreement.
Applied Genetic Technologies Corporation
In July 2015 we entered into a collaboration and license agreement to develop gene-based therapies for 
multiple ophthalmic diseases with Applied Genetic Technologies Corporation (AGTC). This collaboration is focused on 
the development of a portfolio of AGTC’s therapeutic programs, including both a clinical-stage candidate for X-linked 
Retinoschisis (XLRS) and a pre-clinical candidate for the treatment of X-Linked Retinitis Pigmentosa (XLRP). This 
agreement also provides us with options for early stage discovery programs in two ophthalmic diseases and one 
non-ophthalmic condition, as well as an equity investment in AGTC.
Under this agreement we received worldwide commercialization rights for the XLRS and XLRP programs. AGTC 
will lead the clinical development programs of XLRS through product approval and of XLRP through the completion of 
first-in-human trials and we will support the related clinical development costs, subject to certain conditions, 
following the first-in-human study for XLRS and IND-enabling studies for XLRP. AGTC has an option to share 
development costs and profits after the initial clinical trial data becomes available, and an option to co-promote the 
second of these products approved in the U.S.
Upon entering into this agreement we made an upfront payment of $124.0 million to AGTC. AGTC is also 
eligible to receive development, regulatory and commercial milestone payments aggregating in excess of $1.1 billion, 
which includes up to $467.5 million collectively for the two lead programs and up to $592.5 million across the 
discovery programs. AGTC is also eligible to receive royalties in the mid-single digit to mid-teen percentages of 
annual net sales upon successful development and commercialization of new product candidates. 
The $124.0 million upfront payment reflected a $30.0 million equity investment in AGTC, prepaid research and 
development expenditures of $58.4 million and total licensing and other fees of $35.6 million. The $35.6 million in 
total licensing and other fees were recognized as a charge to research and development expense in our consolidated 
statements of income for the year ended December 31, 2015. The $30.0 million equity investment and the $58.4 
million of prepaid research and development expenditures were recorded in investments and other assets in our 
consolidated balance sheets. These prepaid research and development amounts are being expensed as the 
services are provided, of which $11.1 million remains as a prepaid asset as of December 31, 2017. 

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