Attached as Exhibit 99.1 and Exhibit 99.2 to this Current Report
on Form 8-K are slides from presentations that Biogen Inc. made
on December 9, 2016 at the 9th Clinical Trials on Alzheimer’s
Disease (CTAD) meeting in San Diego, California.

Limitation on Incorporation by Reference. The information
furnished in this Item 7.01 shall not be deemed filed for
purposes of Section 18 of the Securities Exchange Act of 1934, as
amended (the Exchange Act), or otherwise subject to the
liabilities of that section, nor shall such information be deemed
incorporated by reference in any filing under the Securities Act
of 1933, as amended, or the Exchange Act except as expressly set
forth by specific reference in such a filing.

Cautionary Note Regarding Forward-Looking Statements.>The
presentations may contain forward-looking statements, including
statements about additional results from the Phase 1b study, and
the potential clinical effects and safety of aducanumab. These
statements may be identified by words such as “believe,”
“expect,” “may,” “plan,” “potential,” “will” and
similar expressions, and are based on our current beliefs and
expectations. Drug development and commercialization involve a
high degree of risk, and only a small number of research and
development programs result in commercialization of a product.
Results in early stage clinical trials may not be indicative of
full results or results from later stage or larger scale clinical
trials and do not ensure regulatory approval. Factors which could
cause actual results to differ materially from our current
expectations include the risk that we may not fully enroll our
clinical trials or enrollment will take longer than expected,
unexpected concerns may arise from additional data, analysis or
results obtained during our clinical trials, regulatory
authorities may require additional information or further
studies, or may fail or refuse to approve or may delay approval
of our drug candidates, or we may encounter other unexpected
hurdles. For more detailed information on the risks and
uncertainties associated with our drug development and
commercialization activities, please review the Risk Factors
section of our most recent annual or quarterly report filed with
the Securities and Exchange Commission. Any forward-looking
statements speak only as of the date of the presentations and we
assume no obligation to update any forward-looking statements.

Item 9.01 Financial Statements and Exhibits