United states securities and exchange commission

Table of Contents
BIOGEN INC. AND SUBSIDIARIES
NOTES TO CONSOLIDATED FINANCIAL STATEMENTS — (Continued)
F- 57
Canada
We and Genentech have assigned our rights under our collaboration agreement with respect to Canada to the 
Roche Group.
GAZYVA
We recognize our share of the development and commercialization expenses of GAZYVA as a reduction of our 
share of pre-tax profits in revenues from anti-CD20 therapeutic programs. 
Commercialization of GAZYVA impacts our percentage of the co-promotion profits for RITUXAN, as summarized 
in the table below.
OCREVUS
In March 2017 the FDA approved OCREVUS, a humanized anti-CD20 monoclonal antibody, for the treatment of 
RMS and PPMS. Under our agreement with Genentech, we will receive a tiered royalty on U.S. net sales from 13.5% 
and increasing up to 24% if annual net sales exceed $900.0 million. There will be a 50% reduction to these royalties 
if a biosimilar to OCREVUS is approved in the U.S. 
In addition, we will receive a 3% royalty on net sales of OCREVUS outside the U.S., with the royalty period 
lasting 11 years from the first commercial sale of OCREVUS on a country-by-country basis. OCREVUS was approved 
for the treatment of RMS and PPMS in Australia, Switzerland and the E.U. in July 2017, September 2017 and 
January 2018, respectively. 
The commercialization of OCREVUS does not impact the percentage of the co-promotion profits we receive for 
RITUXAN or GAZYVA. Genentech is solely responsible for development and commercialization of OCREVUS and 
funding future costs. Genentech cannot develop OCREVUS in CLL, non-Hodgkin's lymphoma or rheumatoid arthritis. 
OCREVUS royalty revenues were based on our estimates from third party and market research data of OCREVUS 
sales occurring during the corresponding period. Differences between actual and estimated royalty revenues will be 
adjusted for in the period in which they become known, which is expected to be the following quarter.
 
Profit-sharing Formulas
RITUXAN Profit Share
Our current pretax co-promotion profit-sharing formula for RITUXAN provides for a 30% share on the first $50.0 
million of co-promotion operating profits earned each calendar year. Our share of annual co-promotion profits in 
excess of $50.0 million varies, as summarized in the table below, upon the following events:
Until GAZYVA First Non-CLL FDA Approval
40.0%
After GAZYVA First Non-CLL FDA Approval until First GAZYVA Threshold Date
39.0%
After First GAZYVA Threshold Date until Second GAZYVA Threshold Date
37.5%
After Second GAZYVA Threshold Date
35.0%
First Non-CLL GAZYVA FDA Approval means the FDA’s first approval of GAZYVA in an indication other than CLL.
First GAZYVA Threshold Date means the earlier of (i) the date of the First Non-CLL GAZYVA FDA approval if U.S. 
gross sales of GAZYVA for the preceding consecutive 12-month period were at least $150.0 million or (ii) the 
first day of the calendar quarter after the date of the First Non-CLL GAZYVA FDA Approval that U.S. gross sales 
of GAZYVA within any consecutive 12-month period have reached $150.0 million.
Second GAZYVA Threshold Date means the first day of the calendar quarter after U.S. gross sales of GAZYVA 
within any consecutive 12-month period have reached $500.0 million. The Second GAZYVA Threshold Date can 
be achieved regardless of whether GAZYVA has been approved in a non-CLL indication.
Our share of RITUXAN pre-tax profits in the U.S. decreased to 39% from 40% in February 2016 when GAZYVA 
was approved by the FDA as a new treatment for follicular lymphoma and was further decreased to 37.5% in the 
third quarter of 2017 as gross sales of GAZYVA in the U.S. for the preceding 12 month period exceeded $150.0 
million.

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Table of Contents
BIOGEN INC. AND SUBSIDIARIES
NOTES TO CONSOLIDATED FINANCIAL STATEMENTS — (Continued)
F- 58
In addition, should the FDA approve an anti-CD20 product other than OCREVUS or GAZYVA that is acquired or 
developed by Genentech and subject to the collaboration agreement, our share of the co-promotion operating profits 
would be between 30% and 37.5% based on certain events.
In June 2017 the FDA approved RITUXAN HYCELA for subcutaneous injection for the treatment of adults with 
previously untreated and relapsed or refractory follicular lymphoma, previously untreated diffuse large B-cell 
lymphoma and CLL. This new treatment includes the same monoclonal antibody as intravenous RITUXAN in 
combination with hyaluronidase human, an enzyme that helps to deliver rituximab under the skin. 
GAZYVA Profit Share
Our current pretax profit-sharing formula for GAZYVA provides for a 35% share on the first $50.0 million of 
operating profits earned each calendar year. Our share of annual profits in excess of $50.0 million varies, as 
summarized in the table below, upon the following events:
Until First GAZYVA Threshold Date
39.0%
After First GAZYVA Threshold Date until Second GAZYVA Threshold Date
37.5%
After Second GAZYVA Threshold Date
35.0%
In 2017, 2016 and 2015 our share of operating profits on GAZYVA was 35%.
In November 2017 the FDA approved GAZYVA in combination with chemotherapy, followed by GAZYVA alone, for 
people with previously untreated advanced follicular lymphoma.
Revenues from Anti-CD20 Therapeutic Programs
Revenues from anti-CD20 therapeutic programs are summarized as follows:
 
For the Years Ended December 31,
(In millions)
2017
2016
2015
Biogen's share of pre-tax profits in the U.S. for RITUXAN and
GAZYVA, including the reimbursement of selling and
development expenses
$
1,316.4
$
1,249.5 $
1,269.8
Other revenues from anti-CD20 therapeutic programs
242.8
65.0
69.4
Total revenues from anti-CD20 therapeutic programs
$
1,559.2
$
1,314.5 $
1,339.2
In 2017 the 37.5% profit-sharing threshold was met during the third quarter and the 39% profit-sharing 
threshold was met during the first quarter. In 2016 the 39% profit-sharing threshold was met during the first quarter. 
In 2015, the 40% profit-sharing threshold was met during the first quarter.
Biogen's share of pre-tax profits in the U.S. for RITUXAN and GAZYVA, including the reimbursement of selling 
and development expenses for 2017, as depicted in the table above, excludes certain expenses charged to the 
collaboration by Genentech that we believe remain the responsibility of Genentech and that we are not obligated to 
pay under the terms of the collaboration agreement. Accordingly, we did not recognize the effect of those expenses 
in the determination of our share of pre-tax collaboration profits and Genentech has withheld approximately $120 
million from amounts due to us in relation to collaboration activity for 2017, representing Genentech’s estimate of 
our share of these expenses. We remain in discussions with Genentech about a resolution relating to these 
amounts.
Prior to regulatory approval, we record our share of the expenses incurred by the collaboration for the 
development of anti-CD20 products in research and development expense in our consolidated statements of 
income. After an anti-CD20 product is approved, we record our share of the development expenses related to that 
product as a reduction of our share of pre-tax profits in revenues from anti-CD20 therapeutic programs. 

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