Biogen : Annual Stockholder Presentation 2022

Business Overview

2022 Annual Meeting of Stockholders

Michel Vounatsos, Chief Executive Officer

June 15, 2022

Forward-looking statements

This presentation and the discussions during this Annual Meeting contain forward-looking statements, including statements made pursuant to the safe harbor provisions of the Private Securities Litigation Reform Act of 1995, relating to: our strategy and plans; potential of, and expectations for, our commercial business and pipeline programs; capital allocation and investment strategy; clinical development programs, clinical trials, and data readouts and presentations; risks and uncertainties associated with drug development and commercialization; regulatory discussions, submissions, filings, and approvals and the timing thereof; the potential benefits, safety, and efficacy of our and our collaboration partners' products and investigational therapies; the anticipated benefits and potential of investments, collaborations, and business development activities; our future financial and operating results; 2022 financial guidance; plans relating to share repurchases. These forward-looking statements may be accompanied by such words as "aim," "anticipate," "believe," "could," "estimate," "expect," "forecast," "goal," "intend," "may," "plan," "potential," "possible," "prospect," "will," "would," and other words and terms of similar meaning. 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. You should not place undue reliance on these statements or the scientific data presented.

These statements involve risks and uncertainties that could cause actual results to differ materially from those reflected in such statements, including: our dependence on sales from our products; the impact of the final NCD; uncertainty of long-term success in developing, licensing, or acquiring other product candidates or additional indications for existing products; risks and uncertainty as to whether the anticipated benefits of the transaction with Samsung Biologics can be achieved; uncertainty as to whether the anticipated benefits of the cost-reduction and productivity measures can be achieved; failure to compete effectively due to significant product competition in the markets for our products; failure to successfully execute or realize the anticipated benefits of our strategic and growth initiatives; difficulties in obtaining and maintaining adequate coverage, pricing, and reimbursement for our products; our dependence on collaborators, joint venture partners, and other third parties for the development, regulatory approval, and commercialization of products and other aspects of our business, which are outside of our full control; the potential impact of the conflict in Ukraine; risks associated with current and potential future healthcare reforms; risks related to commercialization of biosimilars; failure to obtain, protect, and enforce our data, intellectual property, and other proprietary rights and the risks and uncertainties relating to intellectual property claims and challenges; the risk that positive results in a clinical trial may not be replicated in subsequent or confirmatory trials or success in early stage clinical trials may not be predictive of results in later stage or large scale clinical trials or trials in other potential indications; risks associated with clinical trials, including our ability to adequately manage clinical activities, unexpected concerns that may arise from additional data or analysis obtained during clinical trials, regulatory authorities may require additional information or further studies, or may fail to approve or may delay approval of our drug candidates; the occurrence of adverse safety events, restrictions on use with our products, or product liability claims; risks relating to the distribution and sale by third parties of counterfeit or unfit versions of our products; risks relating to the use of social media for our business; risks relating to technology failures or breaches; risks relating to management and key personnel changes, including attracting and retaining key personnel; failure to comply with legal and regulatory requirements; the risks of doing business internationally, including currency exchange rate fluctuations; risks relating to investment in our manufacturing capacity; problems with our manufacturing processes; fluctuations in our effective tax rate; the direct and indirect impacts of the ongoing COVID-19 pandemic on our business, results of operations, and financial condition; fluctuations in our operating results; risks related to investment in properties; the market, interest, and credit risks associated with our investment portfolio; risks relating to share repurchase programs; risks relating to access to capital and credit markets; risks related to indebtedness; change in control provisions in certain of our collaboration agreements; environmental risks; and any other risks and uncertainties that are described in other reports we have filed with the U.S. Securities and Exchange Commission.

These statements are based on our current beliefs and expectations and speak only as of the date of this presentation. We do not undertake any obligation to publicly update any forward- looking statements.

2

Potential for renewed growth and value creation over time

Achieved or Expected 2022 Milestone

GENETIC

NEURODEVELOPMENTAL

PARKINSON'S DISEASE /

MOVEMENT DISORDERS

LUPUS

STROKE

DEPRESSIONNEUROPSYCHIATRY

ALZHEIMER'SALZHEIMER'S

	BIOSIMILARS	BIOSIMILAR LAUNCHES	BIOSIMILAR LAUNCHES
	SPINAL MUSCULAR ATROPHY	NEUROMUSCULAR	NEUROMUSCULAR
MULTIPLE SCLEROSIS	MULTIPLE SCLEROSIS	MULTIPLE SCLEROSIS	MULTIPLE SCLEROSIS
Pre - 2016	2016 - 2021	2022 - 2025	2026-2030
	BUSINESS DEVELOPMENT
		DIGITAL HEALTH

3

3

Continuing to lead and invest in multiple sclerosis

MS Patients

343k	346k	357k	342k	344k

2017	2018	2019	2020	2021
AVONEX		PLEGRIDY		TYSABRI		TECFIDERA		VUMERITY

2021 Highlights

• 2021 revenue of $7.1 billion, including OCREVUS royalties
• VUMERITY continued to grow in U.S. and E.U.
• Intramuscular PLEGRIDY launched in both the U.S. and E.U.
• Subcutaneous TYSABRI launched in the E.U.
• Continuing to pursue new treatment options
• • InnoCare collaboration for an oral BTK inhibitor

Note: Patient numbers represent estimated ending patient count as of December 31	st	4	4
	of each year.

Continued leadership position in SMA

SPINRAZA Patients1

11,150

10,000

6,220

3,230

11,720

2021 Highlights

• 2021 revenue of $1.9 billion

• Over 11,000 patients on therapy1

• Proven efficacy across all patient types and a

well characterized safety profile

• Obtained reimbursement for SPINRAZA in China

• Strengthening our competitive positioning in

SMA, pursuing:

- New ASO that may have the potential for

extended dosing intervals

- Additional analyses on real-world evidence

confirming efficacy in adults

- Higher dose for even greater efficacy

2017

2018

2019

2020

2021

- Potential benefit following sub-optimal response

to competitor's gene therapy and oral

treatments

1. Total patients across the post-marketing setting, the Expanded Access Program, and clinical trials.
ASO = antisense oligonucleotide	5	5