BIIB US Equity☆

ITEM 1A. RISK FACTORS

Risks Related to Our Business

We are substantially dependent on revenue from our products.

Our revenue depends upon continued sales of our products as well as the financial rights we have in our anti-CD20 therapeutic programs. A significant portion of our revenue is concentrated on sales of our products in increasingly competitive markets and in markets affected directly and indirectly by the COVID-19 pandemic. Any of the following negative developments relating to any of our products or any of our anti-CD20 therapeutic programs may adversely affect our revenue and results of operations or could cause a decline in our stock price:

•the introduction or greater acceptance of competing products, including new originator therapies, generics, prodrugs and biosimilars of existing products and products approved under abbreviated regulatory pathways;

•safety or efficacy issues;

•limitations and additional pressures on product pricing or price increases, including those resulting from governmental or regulatory requirements; increased competition, including from generic or biosimilar versions of our products; or changes in, or implementation of, reimbursement policies and practices of payors and other third-parties;

•adverse legal, administrative, regulatory or legislative developments;

•our ability to maintain a positive reputation among patients, healthcare providers and others, which may be impacted by our pricing and reimbursement decisions; or

•the inability or reluctance of patients to receive a diagnosis, prescription or administration of our products or a decision to prescribe and administer competitive therapies as a direct or indirect result of the COVID-19 pandemic.

ADUHELM is in the early stages of commercial launch in the U.S. In addition to risks associated with new product launches and the other factors described in these Risk Factors, our ability to successfully commercialize ADUHELM may be adversely affected due to:

•the lack of readiness of healthcare providers to initiate treatment as well as our ability to successfully identify eligible patients based on the information included in ADUHELM’s label;

•concern regarding the accelerated approval of ADUHELM and its data;

•our ability to obtain and maintain reimbursement for ADUHELM;

•the lack of market acceptance of ADUHELM;

•the effectiveness of our commercial strategy for marketing ADUHELM;

•delays in the manufacturing, distribution and supply of ADUHELM;

•the approval of other new products for the same or similar indications; and

•our ability to maintain a positive reputation among patients, healthcare providers and others in the Alzheimer’s disease community, which may be impacted by pricing and reimbursement decisions relating to ADUHELM.

As part of the accelerated approval, we will conduct a confirmatory trial to verify the clinical benefit of ADUHELM in patients with Alzheimer's disease. The FDA may withdraw approval if, among other things, the confirmatory trial fails to verify clinical benefit, ADUHELM's benefit-risk is no longer positive or we fail to comply with the conditions of the accelerated approval.

Our long-term success depends upon the successful development of new products and additional indications for our existing products.

Our long-term success will depend upon the successful development of new products from our research and development activities or our licenses or acquisitions from third-parties, including our commercialization agreements with Samsung Bioepis, as well as additional indications for our existing products.

Product development is very expensive and involves a high degree of uncertainty and risk and may not be successful. Only a small number of research and development programs result in the commercialization of a product.

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It is difficult to predict the success and the time and cost of product development of novel approaches for the treatment of diseases. The development of novel approaches for the treatment of diseases, including development efforts in new modalities such as those based on the antisense oligonucleotide platform and gene therapy, may present additional challenges and risks, including obtaining approval from regulatory authorities that have limited experience with the development of such therapies.

Clinical trial data are subject to differing interpretations and even if we view data as sufficient to support the safety, effectiveness and/or approval of an investigational therapy, regulatory authorities may disagree and may require additional data, limit the scope of the approval or deny approval altogether. Furthermore, the approval of a product candidate by one regulatory agency does not mean that other regulatory agencies will also approve such product candidate.

Success in preclinical work or early stage clinical trials does not ensure that later stage or larger scale clinical trials will be successful. Clinical trials may indicate that our product candidates lack efficacy, have harmful side effects, result in unexpected adverse events or raise other concerns that may significantly reduce the likelihood of regulatory approval. This may result in terminated programs, significant restrictions on use and safety warnings in an approved label, adverse placement within the treatment paradigm or significant reduction in the commercial potential of the product candidate.

Even if we could successfully develop new products or indications, we may make a strategic decision to discontinue development of a product candidate or indication if, for example, we believe commercialization will be difficult relative to the standard of care or we prefer to pursue other opportunities in our pipeline.

Sales of new products or products with additional indications may not meet investor expectations.

If we fail to compete effectively, our business and market position would suffer.

The biopharmaceutical industry and the markets in which we operate are intensely competitive. We compete in the marketing and sale of our products, the development of new products and processes, the acquisition of rights to new products with commercial potential and the hiring and retention of personnel. We compete with biotechnology and pharmaceutical companies that have a greater number of products on the market and in the product pipeline, substantially greater financial, marketing, research and development and other resources and other technological or competitive advantages.

Our products continue to face increasing competition from the introduction of new originator therapies, generics, prodrugs and biosimilars of existing products and products approved under abbreviated regulatory pathways. Some of these products are likely to be sold at substantially lower prices than our branded products. The introduction of such products as well as other lower-priced competing products has reduced, and may in the future, significantly reduce both the price that we are able to charge for our products and the volume of products we sell, which will negatively impact our revenue. For instance, demand and price for TECFIDERA declined significantly as a result of multiple TECFIDERA generic entrants entering the U.S. market in 2020. In addition, in some markets, when a generic or biosimilar version of one of our products is commercialized, it may be automatically substituted for our product and significantly reduce our revenue in a short period of time.

Our ability to compete, maintain and grow our business may also be adversely affected due to a number of factors, including:

•the introduction of other products, including products that may be more efficacious, safer, less expensive or more convenient alternatives to our products, including our own products and products of our collaborators;

•the off-label use by physicians of therapies indicated for other conditions to treat patients;

•patient dynamics, including the size of the patient population and our ability to identify, attract and maintain new and current patients to our therapies;

•the reluctance of physicians to prescribe, and patients to use, our products without additional data on the efficacy and safety of such products;

•damage to physician and patient confidence in any of our products, generic or biosimilars of our products or any other product from the same class as one of our products, or to our sales and reputation as a result of label changes, pricing and reimbursement decisions or adverse experiences or events that may occur with patients treated with our products or generic or biosimilars of our products;

•inability to obtain appropriate pricing and reimbursement for our products compared to our competitors in key international markets; or

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•our ability to obtain and maintain patent, data or market exclusivity for our products.

Our business may be adversely affected if we do not successfully execute or realize the anticipated benefits of our strategic and growth initiatives.

The successful execution of our strategic and growth initiatives may depend upon internal development projects, commercial initiatives and external opportunities, which may include the acquisition and in-licensing of products, technologies and companies or the entry into strategic alliances and collaborations.

While we believe we have a number of promising programs in our pipeline, failure or delay of internal development projects to advance or difficulties in executing on our commercial initiatives could impact our current and future growth, resulting in additional reliance on external development opportunities for growth.

Supporting the further development of our existing products and potential new products in our pipeline will require significant capital expenditures and management resources, including investments in research and development, sales and marketing, manufacturing capabilities and other areas of our business. We have made, and may continue to make, significant operating and capital expenditures for potential new products prior to regulatory approval with no assurance that such investment will be recouped, which may adversely affect our financial condition, business and operations.

The availability of high quality, fairly valued external product development is limited and the opportunity for their acquisition is highly competitive. As such, we are not certain that we will be able to identify suitable candidates for acquisition or if we will be able to reach agreement.

We may fail to initiate or complete transactions for many reasons, including failure to obtain regulatory or other approvals as well as disputes or litigation. Furthermore, we may not be able to achieve the full strategic and financial benefits expected to result from transactions, or the benefits may be delayed or not occur at all. We may also face additional costs or liabilities in completed transactions that were not contemplated prior to completion.

Any failure in the execution of a transaction, in the integration of an acquired asset or business or in achieving expected synergies could result in slower growth, higher than expected costs, the recording of asset impairment charges and other actions which could adversely affect our business, financial condition and results of operations.

Sales of our products depend, to a significant extent, on adequate coverage, pricing and reimbursement from third-party payors, which are subject to increasing and intense pressure from political, social, competitive and other sources. Our inability to obtain and maintain adequate coverage, or a reduction in pricing or reimbursement, could have an adverse effect on our business, reputation, revenue and results of operations.

Sales of our products depend, to a significant extent, on adequate coverage, pricing and reimbursement from third-party payors. When a new pharmaceutical product is approved, the availability of government and private reimbursement for that product may be uncertain, as is the pricing and amount for which that product will be reimbursed.

Pricing and reimbursement for our products may be adversely affected by a number of factors, including:

•changes in, and implementation of, federal, state or foreign government regulations or private third-party payors’ reimbursement policies;

•pressure by employers on private health insurance plans to reduce costs;

•consolidation and increasing assertiveness of payors seeking price discounts or rebates in connection with the placement of our products on their formularies and, in some cases, the imposition of restrictions on access or coverage of particular drugs or pricing determined based on perceived value;

•our ability to recieve reimbursement for our products; and

•our value-based contracting program pursuant to which we aim to tie the pricing of our products to their clinical values by either aligning price to patient outcomes or adjusting price for patients who discontinue therapy for any reason, including efficacy or tolerability concerns.

Our ability to set the price for our products varies significantly from country to country and, as a result, so can the price of our products. Certain countries set prices by reference to the prices in other countries where our products are marketed. Our inability to obtain and maintain adequate prices in a particular country may not only limit the revenue from our products within that country but may also adversely affect our ability to secure acceptable prices in existing and potential new markets, which may limit market growth. This may create the opportunity for

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third-party cross-border trade or influence our decision to sell or not to sell a product, thus adversely affecting our geographic expansion plans and revenue.

Drug prices are under significant scrutiny in the markets in which our products are prescribed. We expect drug pricing and other health care costs to continue to be subject to intense political and societal pressures on a global basis. Competition from current and future competitors may negatively impact our ability to maintain pricing and our market share. New products marketed by our competitors could cause our revenue to decrease due to potential price reductions and lower sales volumes. Additionally, the introduction of generic or biosimilar versions of our products, follow-on products, prodrugs or products approved under abbreviated regulatory pathways may significantly reduce the price that we are able to charge for our products and the volume of products we sell.

Many payors continue to adopt benefit plan changes that shift a greater portion of prescription costs to patients, including more limited benefit plan designs, higher patient co-pay or co-insurance obligations and limitations on patients' use of commercial manufacturer co-pay payment assistance programs (including through co-pay accumulator adjustment or maximization programs). Significant consolidation in the health insurance industry has resulted in a few large insurers and pharmacy benefit managers exerting greater pressure in pricing and usage negotiations with drug manufacturers, significantly increasing discounts and rebates required of manufacturers and limiting patient access and usage. Further consolidation among insurers, pharmacy benefit managers and other payors would increase the negotiating leverage such entities have over us and other drug manufacturers. Additional discounts, rebates, coverage or plan changes, restrictions or exclusions as described above could have a material adverse effect on sales of our affected products.

Our failure to obtain or maintain adequate coverage, pricing or reimbursement for our products could have an adverse effect on our business, reputation, revenue and results of operations.

We depend on relationships with collaborators, joint venture partners and other third-parties for revenue, and for the development, regulatory approval, commercialization and marketing of certain of our products and product candidates, which are outside of our full control.

We rely on a number of collaborative, joint venture and other third-party relationships for revenue and the development, regulatory approval, commercialization and marketing of certain of our products and product candidates. We also outsource certain aspects of our regulatory affairs and clinical development relating to our products and product candidates to third-parties. Reliance on third-parties subjects us to a number of risks, including:

•we may be unable to control the resources our collaborators, joint venture partners or third-parties devote to our programs, products or product candidates;

•disputes may arise under an agreement, including with respect to the achievement and payment of milestones, payment of development or commercial costs, ownership of rights to technology developed, and the underlying agreement may fail to provide us with significant protection or may fail to be effectively enforced if the collaborators, joint ventures partners or third-parties fail to perform;

•the interests of our collaborators, joint venture partners or third-parties may not always be aligned with our interests, and such parties may not pursue regulatory approvals or market a product in the same manner or to the same extent that we would, which could adversely affect our revenue, or may adopt tax strategies that could have an adverse effect on our business, results of operations or financial condition;

•third-party relationships require the parties to cooperate, and failure to do so effectively could adversely affect product sales or the clinical development or regulatory approvals of product candidates under joint control, could result in termination of the research, development or commercialization of product candidates or could result in litigation or arbitration;

•any failure on the part of our collaborators, joint venture partners or third-parties to comply with applicable laws, including tax laws, regulatory requirements and/or applicable contractual obligations or to fulfill any responsibilities they may have to protect and enforce any intellectual property rights underlying our products could have an adverse effect on our revenue as well as involve us in possible legal proceedings; and

•any improper conduct or actions on the part of our collaborators, joint venture partners or third-parties could subject us to civil or criminal investigations and monetary and injunctive penalties, impact the accuracy and timing of our financial reporting and/or adversely impact our ability to conduct business, our operating results and our reputation.

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Certain officers and affiliates of our joint venture partner, Samsung BioLogics, are currently subject to ongoing criminal proceedings that may impact its operations and business or divert the attention of the Samsung Bioepis management team from its ongoing operations. In addition, as Samsung Bioepis is a privately-held entity, our ability to liquidate our investment may be limited and we may realize significantly less than the value of such investment.

Given these risks, there is considerable uncertainty regarding the success of our current and future collaborative efforts. If these efforts fail, our product development or commercialization of new products could be delayed, revenue from products could decline and/or we may not realize the anticipated benefits of these arrangements.

Our results of operations may be adversely affected by current and potential future healthcare reforms.

In the U.S., federal and state legislatures, health agencies and third-party payors continue to focus on containing the cost of health care. Legislative and regulatory proposals, enactments to reform health care insurance programs and increasing pressure from social sources could significantly influence the manner in which our products are prescribed and purchased. For example, provisions of the Patient Protection and Affordable Care Act (PPACA) have resulted in changes in the way health care is paid for by both governmental and private insurers, including increased rebates owed by manufacturers under the Medicaid Drug Rebate Program, annual fees and taxes on manufacturers of certain branded prescription drugs, the requirement that manufacturers participate in a discount program for certain outpatient drugs under Medicare Part D and the expansion of the number of hospitals eligible for discounts under Section 340B of the Public Health Service Act. These changes have had and are expected to continue to have a significant impact on our business.

We may face uncertainties as a result of efforts to repeal, substantially modify or invalidate some or all of the provisions of the PPACA. There is no assurance that the PPACA, as currently enacted or as amended in the future, will not adversely affect our business and financial results, and we cannot predict how future federal or state legislative or administrative changes relating to healthcare reform will affect our business.

There is increasing public attention on the costs of prescription drugs and we expect drug pricing and other health care costs to continue to be subject to intense political and societal pressures on a global basis. For example, two committees of the U.S. House of Representatives are investigating the approval and price of ADUHELM. In addition, there have been, and are expected to continue to be, legislative proposals to address prescription drug pricing. Some of these proposals could have significant effects on our business, including an executive order issued in September 2020 to test a “most favored nation” model for Part B and Part D drugs that tie reimbursement rates to international drug pricing metrics. These actions and the uncertainty about the future of the PPACA and healthcare laws may put downward pressure on pharmaceutical pricing and increase our regulatory burdens and operating costs.

There is also significant economic pressure on state budgets, including as a result of the COVID-19 pandemic, that may result in states increasingly seeking to achieve budget savings through mechanisms that limit coverage or payment for our drugs. In recent years, some states have considered legislation and ballot initiatives that would control the prices of drugs, including laws to allow importation of pharmaceutical products from lower cost jurisdictions outside the U.S. and laws intended to impose price controls on state drug purchases. State Medicaid programs are increasingly requesting manufacturers to pay supplemental rebates and requiring prior authorization by the state program for use of any drug for which supplemental rebates are not being paid. Government efforts to reduce Medicaid expense may lead to increased use of managed care organizations by Medicaid programs. This may result in managed care organizations influencing prescription decisions for a larger segment of the population and a corresponding limitation on prices and reimbursement for our products.

In the E.U. and some other international markets, the government provides health care at low cost to consumers and regulates pharmaceutical prices, patient eligibility or reimbursement levels to control costs for the government-sponsored health care system. Many countries have announced or implemented measures, and may in the future implement new or additional measures, to reduce health care costs to limit the overall level of government expenditures. These measures vary by country and may include, among other things, patient access restrictions, suspensions on price increases, prospective and possible retroactive price reductions and other recoupments and increased mandatory discounts or rebates, recoveries of past price increases and greater importation of drugs from lower-cost countries. These measures have negatively impacted our revenue and may continue to adversely affect our revenue and results of operations in the future.

Our success in commercializing biosimilars is subject to risks and uncertainties inherent in the development, manufacture and commercialization of biosimilars. If we are unsuccessful in such activities, our business may be adversely affected.

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The development, manufacture and commercialization of biosimilar products require specialized expertise and are very costly and subject to complex regulation. Our success in commercializing biosimilars is subject to a number of risks, including:

•Reliance on Third-Parties. We are dependent, in part, on the efforts of Samsung Bioepis, collaboration partners and other third-parties over whom we have limited or no control in the development and manufacturing of biosimilars products. If these third-parties fail to perform successfully, our biosimilar product development or commercialization of biosimilar products could be delayed, revenue from biosimilar products could decline and/or we may not realize the anticipated benefits of these arrangements;

•Regulatory Compliance. Biosimilar products may face regulatory hurdles or delays due to the evolving and uncertain regulatory and commercial pathway of biosimilars products in certain jurisdictions;

•Intellectual Property and Regulatory Challenges. Biosimilar products may face extensive patent clearances, patent infringement litigation, injunctions or regulatory challenges, which could prevent the commercial launch of a product or delay it for many years or result in imposition of monetary damages, penalties or other civil sanctions and damage our reputation;

•Failure to Gain Market and Patient Acceptance. Market success of biosimilar products will be adversely affected if patients, physicians and/or payors do not accept biosimilar products as safe and efficacious products offering a more competitive price or other benefit over existing therapies;

•Ability to Provide Adequate Supply. Manufacturing biosimilars is complex. If we encounter any manufacturing or supply chain difficulties we may be unable to meet higher than anticipated demand. We are dependent on a third-party for the manufacture of our biosimilar products and such third-party may not perform its obligations in a timely and cost-effective manner or in compliance with applicable regulations and may be unable or unwilling to increase production capacity commensurate with demand for our existing or future biosimilar products; and

•Competitive Challenges. Biosimilar products face significant competition, including from innovator products and biosimilar products offered by other companies. Local tendering processes may restrict biosimilar products from being marketed and sold in some jurisdictions. The number of competitors in a jurisdiction, the timing of approval and the ability to market biosimilar products successfully in a timely and cost-effective manner are additional factors that may impact our success and/or the success of Samsung Bioepis in this business area.

Risks Related to Intellectual Property

If we are unable to obtain and maintain adequate protection for our data, intellectual property and other proprietary rights, our business may be harmed.

Our success, including our long-term viability and growth, depends, in part, on our ability to obtain and defend patent and other intellectual property rights, including certain regulatory forms of exclusivity, that are important to the commercialization of our products and product candidates. Patent protection and/or regulatory exclusivity in the U.S. and other important markets remains uncertain and depends, in part, upon decisions of the patent offices, courts, administrative bodies and lawmakers in these countries. We may fail to obtain or preserve patent and other intellectual property rights, including certain regulatory forms of exclusivity, or the protection we obtain may not be of sufficient breadth and degree to protect our commercial interests in all countries where we conduct business, which could result in financial, business or reputational harm to us or could cause a decline or volatility in our stock price. In addition, settlements of such proceedings often result in reducing the period of patent and other protections, resulting in a reduction in revenue from affected products.

In many markets, including the U.S., manufacturers may be allowed to rely on the safety and efficacy data of the innovator's product and do not need to conduct clinical trials before marketing a competing version of a product after there is no longer patent or regulatory exclusivity. In such cases, manufacturers often charge significantly lower prices and a major portion of the company's revenue may be reduced in a short period of time. In addition, manufacturers of generics and biosimilars may choose to launch or attempt to launch their products before the expiration of our patent or other intellectual property protections.

Furthermore, our products may be determined to infringe patents or other intellectual property rights held by third-parties. Legal proceedings, administrative challenges or other types of proceedings are and may in the future be necessary to determine the validity, scope or non-infringement of certain patent rights claimed by third-parties to be pertinent to the manufacture, use or sale of our products. Such proceedings are unpredictable and are often

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protracted and expensive. Negative outcomes of such proceedings could hinder or prevent us from manufacturing and marketing our products, require us to seek a license for the infringed product or technology or result in the assessment of significant monetary damages against us that may exceed amounts, if any, accrued in our financial statements. A failure to obtain necessary licenses for an infringed product or technology could prevent us from manufacturing or selling our products. Furthermore, payments under any licenses that we are able to obtain would reduce our profits from the covered products and services. Any of these circumstances could result in financial, business or reputational harm to us or could cause a decline or volatility in our stock price.

Risks Related to Development, Clinical Testing and Regulation of Our Products and Product Candidates

Successful preclinical work or early stage clinical trials does not ensure success in later stage trials, regulatory approval or commercial viability of a product.

Positive results in a clinical trial may not be replicated in subsequent or confirmatory trials. Additionally, success in preclinical work or early stage clinical trials does not ensure that later stage or larger scale clinical trials will be successful or that regulatory approval will be obtained. Even if later stage clinical trials are successful, regulatory authorities may delay or decline approval of our product candidates. Regulatory authorities may disagree with our view of the data, require additional studies or disagree with our trial design or endpoints. Regulatory authorities may also fail to approve the facilities or processes used to manufacture a product candidate, our dosing or delivery methods or companion devices. Regulatory authorities may grant marketing approval that is more restricted than anticipated, including limiting indications to narrow patient populations and the imposition of safety monitoring, educational requirements, requiring confirmatory trials and risk evaluation and mitigation strategies. For example, as part of the accelerated approval, we will conduct a confirmatory trial to verify the clinical benefit of ADUHELM in patients with Alzheimer's disease. The occurrence of any of these events could result in significant costs and expense, have an adverse effect on our business, financial condition and results of operations and/or cause our stock price to decline or experience periods of volatility.

Clinical trials and the development of biopharmaceutical products is a lengthy and complex process. If we fail to adequately manage our clinical activities, our clinical trials or potential regulatory approvals may be delayed or denied.

Conducting clinical trials is a complex, time-consuming and expensive process. Our ability to complete clinical trials in a timely fashion depends on a number of key factors, including protocol design, regulatory and institutional review board approval, patient enrollment rates and compliance with current Good Clinical Practices. If we or our third-party clinical trial providers or third-party CROs do not successfully carry out these clinical activities, our clinical trials or the potential regulatory approval of a product candidate may be delayed or denied.

We have opened clinical trial sites and are enrolling patients in a number of countries where our experience is limited. In most cases, we use the services of third-parties to carry out our clinical trial related activities and rely on such parties to accurately report their results. Our reliance on third-parties for these activities may impact our ability to control the timing, conduct, expense and quality of our clinical trials. One CRO has responsibility for a substantial portion of our activities and reporting related to our clinical trials and if such CRO does not adequately perform, many of our trials may be affected. We may need to replace our CROs, which may result in the delay of the affected trials or otherwise adversely affect our efforts to obtain regulatory approvals and commercialize our product candidates.

Adverse safety events or restrictions on use and safety warnings for our products can negatively affect our business, product sales and stock price.

Adverse safety events involving our marketed products, generic or biosimilar versions of our marketed products or products from the same class as one of our products may have a negative impact on our business. Discovery of safety issues with our products could create product liability and could cause additional regulatory scrutiny and requirements for additional labeling or safety monitoring, withdrawal of products from the market and/or the imposition of fines or criminal penalties. Adverse safety events may also damage physician, patient and/or investor confidence in our products and our reputation. Any of these could result in adverse impacts on our results of operations.

Regulatory authorities are making greater amounts of stand-alone safety information directly available to the public through periodic safety update reports, patient registries and other reporting requirements. The reporting of adverse safety events involving our products or products similar to ours and public rumors about such events may increase claims against us and may also cause our product sales to decline or our stock price to experience periods of volatility.

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Restrictions on use or safety warnings that may be required to be included in the label of our products may significantly reduce expected revenue for those products and require significant expense and management time.

The illegal distribution and sale by third-parties of counterfeit or unfit versions of our products or stolen products could have a negative impact on our reputation and business.

Third-parties might illegally distribute and sell counterfeit or unfit versions of our products, which do not meet our rigorous manufacturing, distribution and testing standards. A patient who receives a counterfeit or unfit drug may be at risk for a number of dangerous health consequences. Our reputation and business could suffer harm as a result of counterfeit or unfit drugs sold under our brand name. Inventory that is stolen from warehouses, plants or while in-transit, and that is subsequently improperly stored and sold through unauthorized channels, could adversely impact patient safety, our reputation and our business.

The increasing use of social media platforms presents new risks and challenges.

Social media is increasingly being used to communicate about our products and the diseases our therapies are designed to treat. Social media practices in the biopharmaceutical industry continue to evolve and regulations relating to such use are not always clear and creates uncertainty and risk of noncompliance with regulations applicable to our business. For example, patients may use social media channels to comment on the effectiveness of a product or to report an alleged adverse event. When such disclosures occur, there is a risk that we fail to monitor and comply with applicable adverse event reporting obligations or we may not be able to defend the company or the public's legitimate interests in the face of the political and market pressures generated by social media due to restrictions on what we may say about our products. There is also a risk of inappropriate disclosure of sensitive information or negative or inaccurate posts or comments about us on social media. We may also encounter criticism on social media regarding our company, management, product candidates or products. The immediacy of social media precludes us from having real-time control over postings made regarding us via social media, whether matters of fact or opinion. Our reputation could be damaged by negative publicity or if adverse information concerning us is posted on social media platforms or similar mediums, which we may not be able to reverse. If any of these events were to occur or we otherwise fail to comply with applicable regulations, we could incur liability, face restrictive regulatory actions or incur other harm to our business.

Risks Related to Our Operations

A breakdown or breach of our technology systems could subject us to liability or interrupt the operation of our business.

We are increasingly dependent upon technology systems and data to operate our business. The COVID-19 pandemic has caused us to modify our business practices in ways that heighten this dependence, including changing the requirement that most of our office-based employees in the U.S. and our other key markets work from the office. As a result, we are increasingly dependent upon our technology systems to operate our business and our ability to effectively manage our business depends on the security, reliability and adequacy of our technology systems and data, which includes use of cloud technologies, including Software as a Service (SaaS), Platform as a Service (PaaS) and Infrastructure as a Service (IaaS). Breakdowns, invasions, corruptions, destructions and/or breaches of our technology systems, including our cloud technologies, and/or unauthorized access to our data and information could subject us to liability, negatively impact our business operations, and/or require replacement of technology and/or ransom payments. Our technology systems, including our cloud technologies, continue to increase in multitude and complexity, increasing our vulnerability when breakdowns, malicious intrusions and random attacks occur. Data privacy or security breaches also pose a risk that sensitive data, including intellectual property, trade secrets or personal information belonging to us, patients, customers or other business partners, may be exposed to unauthorized persons or to the public.

Cyber-attacks are increasing in their frequency, sophistication and intensity, and are becoming increasingly difficult to detect, when they impact vendors, customers or companies, including vendors, suppliers and other companies in our supply chain. They are often carried out by motivated, well-resourced, skilled and persistent actors, including nation states, organized crime groups, “hacktivists” and employees or contractors acting with careless or malicious intent. Cyber-attacks include deployment of harmful malware and key loggers, ransomware, a denial-of-service attack, a malicious website, the use of social engineering and other means to affect the confidentiality, integrity and availability of our technology systems and data. Cyber-attacks also include manufacturing, hardware or software supply chain attacks, which could cause a delay in the manufacturing of products or products produced for contract manufacturing or lead to a data privacy or security breach. Our key business partners face similar risks and any security breach of their systems could adversely affect our security posture. In addition, our increased use of cloud technologies heightens these and other operational risks, and any failure by cloud or other technology service

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providers to adequately safeguard their systems and prevent cyber-attacks could disrupt our operations and result in misappropriation, corruption or loss of confidential or propriety information.

While we continue to build and improve our systems and infrastructure, including our business continuity plans, there can be no assurance that our efforts will prevent breakdowns or breaches in our systems that could adversely affect our business and operations and/or result in the loss of critical or sensitive information, which could result in financial, legal, operational or reputational harm to us, loss of competitive advantage or loss of consumer confidence. Our liability insurance may not be sufficient in type or amount to cover us against claims related to security breaches, cyber-attacks and other related breaches.

Regulators are imposing new data privacy and security requirements, including new and greater monetary fines for privacy violations. For example, the E.U.’s General Data Protection Regulation established regulations regarding the handling of personal data, and provides an enforcement authority and imposes large penalties for noncompliance. New U.S. data privacy and security laws, such as the California Consumer Privacy Act (CCPA), and others that may be passed, similarly introduce requirements with respect to personal information, and non-compliance with the CCPA may result in liability through private actions (subject to statutorily defined damages in the event of certain data breaches) and enforcement. Failure to comply with these current and future laws, policies, industry standards or legal obligations or any security incident resulting in the unauthorized access to, or acquisition, release or transfer of personal information may result in governmental enforcement actions, litigation, fines and penalties or adverse publicity and could cause our customers to lose trust in us, which could have a material adverse effect on our business and results of operations.

Management and other personnel changes may disrupt our operations, and we may have difficulty retaining personnel or attracting and retaining qualified replacements on a timely basis for the management and other personnel who may leave the Company.

Changes in management, other personnel and our overall retention rate may disrupt our business, and any such disruption could adversely affect our operations, programs, growth, financial condition or results of operations. New members of management may have different perspectives on programs and opportunities for our business, which may cause us to focus on new opportunities or reduce or change emphasis on our existing programs.

Our success is dependent upon our ability to attract and retain qualified management and key personnel in a highly competitive environment. Qualified individuals are in high demand, and we may incur significant costs to attract or retain them. We may face difficulty in attracting and retaining talent for a number of reasons, including management changes, the underperformance or discontinuation of one or more marketed or late stage programs, recruitment by competitors or changes in the overall labor market. In addition, changes in our organizational structure or in our flexible working arrangements could impact employees' productivity and morale as well as our ability to attract, retain and motivate employees. We cannot ensure that we will be able to hire or retain the personnel necessary for our operations or that the loss of any personnel will not have a material impact on our financial condition and results of operations.

If we fail to comply with the extensive legal and regulatory requirements affecting the health care industry, we could face increased costs, penalties and a loss of business.

Our activities, and the activities of our collaborators, distributors and other third-party providers, are subject to extensive government regulation and oversight in the U.S. and in foreign jurisdictions, and are subject to change and evolving interpretations, which could require us to incur substantial costs associated with compliance or to alter one or more of our business practices. The FDA and comparable foreign agencies directly regulate many of our most critical business activities, including the conduct of preclinical and clinical studies, product manufacturing, advertising and promotion, product distribution, adverse event reporting, product risk management and our compliance with good practice quality guidelines and regulations. Our interactions with physicians and other health care providers that prescribe or purchase our products are also subject to government regulation designed to prevent fraud and abuse in the sale and use of products and place significant restrictions on the marketing practices of health care companies. Health care companies are facing heightened scrutiny of their relationships with health care providers and have been the target of lawsuits and investigations alleging violations of government regulation, including claims asserting submission of incorrect pricing information, impermissible off-label promotion of pharmaceutical products, payments intended to influence the referral of health care business, submission of false claims for government reimbursement, antitrust violations or violations related to environmental matters. There is also enhanced scrutiny of company-sponsored patient assistance programs, including insurance premium and co-pay assistance programs and donations to third-party charities that provide such assistance. The U.S. government has challenged some of our donations to third-party charities that provide patient assistance. If we, or our vendors or

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donation recipients, are found to fail to comply with relevant laws, regulations or government guidance in the operation of these programs, we could be subject to significant fines or penalties. Risks relating to compliance with laws and regulations may be heightened as we continue to expand our global operations and enter new therapeutic areas with different patient populations, which may have different product distribution methods, marketing programs or patient assistance programs from those we currently utilize or support.

Conditions and regulations governing the health care industry are subject to change, with possible retroactive effect, including:

•new laws, regulations or judicial decisions, or new interpretations of existing laws, regulations or judicial decisions, related to health care availability, pricing or marketing practices, compliance with employment practices, method of delivery, payment for health care products and services, compliance with health information and data privacy and security laws and regulations, tracking and reporting payments and other transfers of value made to physicians and teaching hospitals, extensive anti-bribery and anti-corruption prohibitions, product serialization and labeling requirements and used product take-back requirements;

•changes in the FDA and foreign regulatory approval processes or perspectives that may delay or prevent the approval of new products and result in lost market opportunity;

•government shutdowns or relocations may result in delays to the review and approval process, slowing the time necessary for new drug candidates to be reviewed and/or approved, which may adversely affect our business;

•requirements that provide for increased transparency of clinical trial results and quality data, such as the EMA's clinical transparency policy, which could impact our ability to protect trade secrets and competitively-sensitive information contained in approval applications or could be misinterpreted leading to reputational damage, misperception or legal action, which could harm our business; and

•changes in FDA and foreign regulations that may require additional safety monitoring, labeling changes, restrictions on product distribution or use or other measures after the introduction of our products to market, which could increase our costs of doing business, adversely affect the future permitted uses of approved products or otherwise adversely affect the market for our products.

Violations of governmental regulation may be punishable by criminal and civil sanctions, including fines and civil monetary penalties and exclusion from participation in government programs, including Medicare and Medicaid, as well as against executives overseeing our business. We could also be required to repay amounts we received from government payors or pay additional rebates and interest if we are found to have miscalculated the pricing information we submitted to the government. In addition, legal proceedings and investigations are inherently unpredictable, and large judgments or settlements sometimes occur. While we believe that we have appropriate compliance controls, policies and procedures in place to comply with the laws or regulations of the jurisdictions in which we operate, there is a risk that acts committed by our employees, agents, distributors, collaborators or third-party providers might violate such laws or regulations. Whether or not we have complied with the law, an investigation or litigation related to alleged unlawful conduct could increase our expense, damage our reputation, divert management time and attention and adversely affect our business.

Our sales and operations are subject to the risks of doing business internationally.

We are increasing our presence in international markets, subjecting us to many risks that could adversely affect our business and revenue. There is no guarantee that our efforts and strategies to expand sales in international markets will succeed. Emerging market countries may be especially vulnerable to periods of global and local political, legal, regulatory and financial instability and may have a higher incidence of corruption and fraudulent business practices. Certain countries may require local clinical trial data as part of the drug registration process in addition to global clinical trials, which can add to overall drug development and registration timelines. We may also be required to increase our reliance on third-party agents and unfamiliar operations and arrangements previously utilized by companies we collaborate with or acquire in emerging markets.

Our sales and operations are subject to the risks of doing business internationally, including:

•the impact of public health epidemics, such as the COVID-19 pandemic, on the global economy and the delivery of healthcare treatments;

•less favorable intellectual property or other applicable laws;

•the inability to obtain necessary foreign regulatory approvals of products in a timely manner;

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•limitations and additional pressures on our ability to obtain and maintain product pricing or receive price increases, including those resulting from governmental or regulatory requirements;

•additional complexity in manufacturing internationally;

•the inability to successfully complete subsequent or confirmatory clinical trials in countries where our experience is limited;

•longer payment and reimbursement cycles and uncertainties regarding the collectability of accounts receivable;

•fluctuations in foreign currency exchange rates that may adversely impact our revenue, net income and value of certain of our investments;

•the imposition of governmental controls;

•diverse data privacy and protection requirements;

•increasingly complex standards for complying with foreign laws and regulations that may differ substantially from country to country and may conflict with corresponding U.S. laws and regulations;

•the far-reaching anti-bribery and anti-corruption legislation in the United Kingdom (U.K.), including the U.K. Bribery Act 2010, and elsewhere and escalation of investigations and prosecutions pursuant to such laws;

•compliance with complex import and export control laws;

•changes in tax laws; and

•the imposition of tariffs or embargoes and other trade restrictions.

In addition, our international operations are subject to regulation under U.S. law. For example, the U.S. Foreign Corrupt Practices Act (FCPA) prohibits U.S. companies and their representatives from paying, offering to pay, promising to pay or authorizing the payment of anything of value to any foreign government official, government staff member, political party or political candidate for the purpose of obtaining or retaining business or to otherwise obtain favorable treatment or influence a person working in an official capacity. In many countries, the health care professionals we regularly interact with may meet the FCPA's definition of a foreign government official. Failure to comply with domestic or foreign laws could result in various adverse consequences, including possible delay in approval or refusal to approve a product, recalls, seizures or withdrawal of an approved product from the market, disruption in the supply or availability of our products or suspension of export or import privileges, the imposition of civil or criminal sanctions, the prosecution of executives overseeing our international operations and damage to our reputation. Any significant impairment of our ability to sell products outside of the U.S. could adversely impact our business and financial results. In addition, while we believe that we have appropriate compliance controls, policies and procedures in place to comply with the FCPA, there is a risk that acts committed by our employees, agents, distributors, collaborators or third-party providers might violate the FCPA and we might be held responsible. If our employees, agents, distributors, collaborators or third-party providers are found to have engaged in such practices, we could suffer severe penalties and may be subject to other liabilities, which could negatively affect our business, operating results and financial condition.

We are building a large-scale biologics manufacturing facility, which will result in the incurrence of significant investment with no assurance that such investment will be recouped.

In order to support our future growth and drug development pipeline, we are expanding our large molecule production capacity by building a large-scale biologics manufacturing facility in Solothurn, Switzerland with no assurance that the additional capacity will be required or this investment will be recouped.

If we are unable to fully utilize our manufacturing facilities, our business may be harmed. Charges resulting from excess capacity may continue to occur and would have a negative effect on our financial condition and results of operations.

Although a portion of the Solothurn facility received a GMP multi-product license from SWISSMEDIC in May 2021, the manufacturing of a product or product candidate at the Solothurn facility must be approved by the applicable regulatory agencies, including the FDA. There can be no assurance that the regulatory authorities will approve the Solothurn facility for the manufacturing of a product or a product candidate. If we do not receive the necessary regulatory approvals of the Solothurn facility or if our future growth and drug development plans increase, we may not have sufficient large-scale manufacturing capacity to meet our long-term manufacturing requirements.

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Manufacturing issues could substantially increase our costs, limit supply of our products and/or reduce our revenue.

The process of manufacturing our products is complex, highly regulated and subject to numerous risks, including:

•Risks of Reliance on Third-Parties and Single Source Providers. We rely on third-party suppliers and manufacturers for many aspects of our manufacturing process for our products and product candidates. In some cases, due to the unique manner in which our products are manufactured, we rely on single source providers of raw materials and manufacturing supplies. These third-parties are independent entities subject to their own unique operational and financial risks that are outside of our control. These third-parties may not perform their obligations in a timely and cost-effective manner or in compliance with applicable regulations, and they may be unable or unwilling to increase production capacity commensurate with demand for our existing or future products. Finding alternative providers could take a significant amount of time and involve significant expense due to the specialized nature of the services and the need to obtain regulatory approval of any significant changes to our suppliers or manufacturing methods. We cannot be certain that we could reach agreement with alternative providers or that the FDA or other regulatory authorities would approve our use of such alternatives. Furthermore, factors such as the COVID-19 pandemic, weather events, labor or raw material shortages and other supply chain disruptions could result in difficulties and delays in manufacturing our products, which could have an adverse impact on our results in operations or result in product shortages.

•Global Bulk Supply Risks. We rely on our manufacturing facilities for the production of drug substance for our large molecule products and product candidates. Our global bulk supply of these products and product candidates depends on the uninterrupted and efficient operation of these facilities, which could be adversely affected by equipment failures, labor or raw material shortages, public health epidemics, natural disasters, power failures, cyber-attacks and many other factors.

•Risks Relating to Compliance with current GMP (cGMP). We and our third-party providers are generally required to maintain compliance with cGMP and other stringent requirements and are subject to inspections by the FDA and other regulatory authorities to confirm compliance. Any delay, interruption or other issues that arise in the manufacture, fill-finish, packaging or storage of our products as a result of a failure of our facilities or operations or those of third-parties to receive regulatory approval or pass any regulatory agency inspection could significantly impair our ability to develop and commercialize our products. Significant noncompliance could also result in the imposition of monetary penalties or other civil or criminal sanctions and damage our reputation.

•Risk of Product Loss. The manufacturing process for our products is extremely susceptible to product loss due to contamination, oxidation, equipment failure or improper installation or operation of equipment or vendor or operator error. Even minor deviations from normal manufacturing processes could result in reduced production yields, product defects and other supply disruptions. If microbial, viral or other contaminations are discovered in our products or manufacturing facilities, we may need to close our manufacturing facilities for an extended period of time to investigate and remediate the contaminant.

•Risk Relating to Government Actions. We and/or our third-party providers may be required by the U.S. federal government to manufacture medical supplies needed to treat COVID-19 patients under the Defense Production Act or other acts or orders of government entities, which may result in delays in the manufacturing and supply of our products.

Any adverse developments affecting our manufacturing operations or the operations of our third-party suppliers and manufacturers may result in shipment delays, inventory shortages, lot failures, product withdrawals or recalls or other interruptions in the commercial supply of our products. We may also have to take inventory write-offs and incur other charges and expense for products that fail to meet specifications, undertake costly remediation efforts or seek more costly manufacturing alternatives. Such developments could increase our manufacturing costs, cause us to lose revenue or market share as patients and physicians turn to competing therapeutics, diminish our profitability or damage our reputation.

In addition, although we have business continuity plans to reduce the potential for manufacturing disruptions or delays and reduce the severity of a disruptive event, there is no guarantee that these plans will be adequate, which could adversely affect our business and operations.

The ongoing COVID-19 pandemic may, directly or indirectly, adversely affect our business, results of operations and financial condition.

Our business has and could continue to be adversely affected, directly or indirectly, by the ongoing COVID-19 pandemic. National, state and local governments have implemented and may continue to implement safety

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precautions. These measures may disrupt normal business operations and may have significant negative impacts on businesses and financial markets worldwide.

We continue to monitor our operations and applicable government recommendations, and we have made modifications to our normal operations because of the COVID-19 pandemic, including limiting travel and working from home. We have also suspended the vast majority of our in-person interactions by our customer-facing professionals in healthcare settings. This limits our ability to market our products and educate physicians, which, in turn, could have an adverse effect on our ability to compete in the marketing and sales of our products.

Changes in flexible working arrangements could impact employee retention, employees' productivity and morale, strain our technology resources and introduce operational risks. Additionally, the risk of cyber-attacks or other privacy or data security incidents may be heightened as a result of our moving increasingly towards a remote working environment, which may be less secure and more susceptible to hacking attacks.

The COVID-19 pandemic could affect the health and availability of our workforce as well as those of the third-parties we rely on. Furthermore, delays and disruptions experienced by our collaborators, joint venture partners or other third-parties due to the COVID-19 pandemic could adversely impact the ability of such parties to fulfill their obligations, which could affect product sales or the clinical development or regulatory approvals of product candidates under joint control.

Our ability to continue our existing clinical trials or to initiate new clinical trials has been and may continue to be adversely affected, directly or indirectly, by the COVID-19 pandemic. Restrictions on travel and/or transport of clinical materials as well as diversion of hospital staff and resources to COVID-19 infected patients could disrupt trial operations and recruitment, possibly resulting in a slowdown in enrollment and/or deviations from or disruptions in key clinical trial activities, such as clinical trial site monitoring. These challenges may lead to difficulties in meeting protocol-specified procedures. We may need to make certain adjustments to the operation of clinical trials in an effort to minimize risks to trial data integrity during the COVID-19 pandemic. In addition, the impact of the COVID-19 pandemic on the operations of the FDA and other health authorities may delay potential approvals of our product candidates.

In response to the COVID-19 pandemic, legislation has been enacted aimed at providing emergency assistance and health care for individuals, families and businesses and broadly supporting the U.S. economy. Additional state and federal healthcare reform measures may be adopted in the future, any of which could limit the amounts that federal and state governments will pay for healthcare products and services, which could result in reduced demand for our products or additional pricing pressures and have a financial impact on our business that we cannot predict.

While it is not possible at this time to estimate the entirety of the impact that the COVID-19 pandemic will have on our business, operations, employees, customers, suppliers or collaboration partners, continued spread of COVID-19, measures taken by governments, actions taken to protect employees and the broad impact of the pandemic on all business activities may materially and adversely affect our business, supply chain and distribution systems, results of operations and financial condition.

Risks Related to Holding Our Common Stock

Our operating results are subject to significant fluctuations.

Our quarterly revenue, expense and net income (loss) have fluctuated in the past and are likely to fluctuate significantly in the future due to the risks described in these Risk Factors as well as the timing of charges and expense that we may take. We have recorded, or may be required to record, charges that include:

•the cost of restructurings or other initiatives to streamline our operations and reallocate resources;

•impairments with respect to investments, fixed assets and long-lived assets, including in-process research and development (IPR&D) and other intangible assets;

•inventory write-downs for failed quality specifications, recurring charges for excess or obsolete inventory and charges for inventory write-downs relating to product suspensions, expirations or recalls;

•changes in the fair value of contingent consideration or our equity investments;

•bad debt expense and increased bad debt reserves;

•outcomes of litigation and other legal or administrative proceedings, regulatory matters and tax matters;

•payments in connection with acquisitions, divestitures and other business development activities and under license and collaboration agreements;

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•failure to meet certain contractual commitments; and

•the impact of public health epidemics, such as the COVID-19 pandemic, on employees, the global economy and the delivery of healthcare treatments.

Our revenue and certain assets and liabilities are also subject to foreign currency exchange rate fluctuations due to the global nature of our operations. Our efforts to mitigate the impact of fluctuating currency exchange rates may not be successful. As a result, currency fluctuations among our reporting currency, the U.S. dollar, and other currencies in which we do business will affect our operating results, often in unpredictable ways. Our net income may also fluctuate due to the impact of charges we may be required to take with respect to foreign currency hedge transactions. In particular, we may incur higher than expected charges from early termination of a hedge relationship.

Our operating results during any one period do not necessarily suggest the anticipated results of future periods.

Our investments in properties may not be fully realized.

We own or lease real estate primarily consisting of buildings that contain research laboratories, office space and manufacturing operations. We may decide to consolidate or co-locate certain aspects of our business operations or dispose of one or more of our properties, some of which may be located in markets that are experiencing high vacancy rates and decreasing property values. If we determine that the fair value of any of our owned properties is lower than their book value, we may not realize the full investment in these properties and incur significant impairment charges or additional depreciation when the expected useful lives of certain assets have been shortened due to the anticipated closing of facilities. If we decide to fully or partially vacate a property, we may incur significant cost, including facility closing costs, employee separation and retention expense, lease termination fees, rent expense in excess of sublease income and impairment of leasehold improvements and accelerated depreciation of assets. Any of these events may have an adverse impact on our results of operations.

Our investment portfolio is subject to market, interest and credit risk that may reduce its value.

We maintain a portfolio of marketable securities for investment of our cash as well as investments in equity securities of certain biotechnology companies. Changes in the value of our investment portfolio could adversely affect our earnings. The value of our investments may decline due to, among other things, increases in interest rates, downgrades of the bonds and other securities in our portfolio, negative company-specific news, biotechnology market sentiment, instability in the global financial markets that reduces the liquidity of securities in our portfolio, declines in the value of collateral underlying the securities in our portfolio and other factors. Each of these events may cause us to record charges to reduce the carrying value of our investment portfolio or sell investments for less than our acquisition cost. Although we attempt to mitigate these risks through diversification of our investments and continuous monitoring of our portfolio's overall risk profile, the value of our investments may nevertheless decline.

There can be no assurance that we will continue to repurchase shares or that we will repurchase shares at favorable prices.

From time to time our Board of Directors authorizes share repurchase programs. The amount and timing of share repurchases are subject to capital availability and our determination that share repurchases are in the best interest of our shareholders and are in compliance with all respective laws and our applicable agreements. Our ability to repurchase shares will depend upon, among other factors, our cash balances and potential future capital requirements for strategic transactions, our results of operations, our financial condition and other factors beyond our control that we may deem relevant. A reduction in repurchases under, or the completion of, our share repurchase programs could have a negative effect on our stock price. We can provide no assurance that we will repurchase shares at favorable prices, if at all.

We may not be able to access the capital and credit markets on terms that are favorable to us.

We may seek access to the capital and credit markets to supplement our existing funds and cash generated from operations for working capital, capital expenditure and debt service requirements and other business initiatives. The capital and credit markets are experiencing, and have in the past experienced, extreme volatility and disruption, which leads to uncertainty and liquidity issues for both borrowers and investors. In the event of adverse market conditions, we may be unable to obtain capital or credit market financing on favorable terms. Changes in credit ratings issued by nationally recognized credit rating agencies could also adversely affect our cost of financing and the market price of our securities.

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Our indebtedness could adversely affect our business and limit our ability to plan for or respond to changes in our business.

Our indebtedness, together with our significant contingent liabilities, including milestone and royalty payment obligations, could have important consequences to our business; for example, such obligations could:

•increase our vulnerability to general adverse economic and industry conditions;

•limit our ability to access capital markets and incur additional debt in the future;

•require us to dedicate a substantial portion of our cash flow from operations to payments on our indebtedness, thereby reducing the availability of our cash flow for other purposes, including business development, research and development and mergers and acquisitions; and

•limit our flexibility in planning for, or reacting to, changes in our business and the industry in which we operate, thereby placing us at a disadvantage compared to our competitors that have less debt.

Some of our collaboration agreements contain change in control provisions that may discourage a third-party from attempting to acquire us.

Some of our collaboration agreements include change in control provisions that could reduce the potential acquisition price an acquirer is willing to pay or discourage a takeover attempt that could be viewed as beneficial to shareholders. Upon a change in control, some of these provisions could trigger reduced milestone, profit or royalty payments to us or give our collaboration partner rights to terminate our collaboration agreement, acquire operational control or force the purchase or sale of the programs that are the subject of the collaboration.

General Risk Factors

Our effective tax rate fluctuates, and we may incur obligations in tax jurisdictions in excess of accrued amounts.

As a global biopharmaceutical company, we are subject to taxation in numerous countries, states and other jurisdictions. As a result, our effective tax rate is derived from a combination of applicable tax rates, including withholding taxes, in the various places that we operate. In preparing our financial statements, we estimate the amount of tax that will become payable in each of such places. Our effective tax rate may be different than experienced in the past or our current expectations due to many factors, including changes in the mix of our profitability from country to country, the results of examinations and audits of our tax filings (including those related to the impact of the Tax Cuts and Jobs Act of 2017), adjustments to the value of our uncertain tax positions, interpretations by tax authorities or other bodies with jurisdiction, the result of tax cases, changes in accounting for income taxes and changes in tax laws and regulations either prospectively or retrospectively.

Our inability to secure or sustain acceptable arrangements with tax authorities and future changes in the tax laws, among other things, may result in tax obligations in excess of amounts accrued in our financial statements.

The enactment of some or all of the recommendations set forth or that may be forthcoming in the Organization for Economic Cooperation and Development’s project on “Base Erosion and Profit Shifting” (BEPS) by tax authorities and economic blocs in the countries in which we operate, could unfavorably impact our effective tax rate. These initiatives focus on common international principles for the entitlement to taxation of global corporate profits and minimum global tax rates.

Our business involves environmental risks, which include the cost of compliance and the risk of contamination or injury.

Our business and the business of several of our strategic partners involve the controlled use of hazardous materials, chemicals, biologics and radioactive compounds. Although we believe that our safety procedures for handling and disposing of such materials comply with state, federal and foreign standards, there will always be the risk of accidental contamination or injury. If we were to become liable for an accident, or if we were to suffer an extended facility shutdown, we could incur significant costs, damages and penalties that could harm our business. Manufacturing of our products and product candidates also requires permits from government agencies for water supply and wastewater discharge. If we do not obtain appropriate permits, including permits for sufficient quantities of water and wastewater, we could incur significant costs and limits on our manufacturing volumes that could harm our business.

ITEM 1B. UNRESOLVED STAFF COMMENTS

None.

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ITEM 2. PROPERTIES

Below is a summary of our owned and leased properties as of December 31, 2021.

Massachusetts

In Cambridge, MA we own approximately 508,000 square feet of real estate space, consisting of a building that houses a research laboratory and a cogeneration plant totaling approximately 263,000 square feet and a building that contains research, development and quality laboratories totaling approximately 245,000 square feet.

In addition, we lease a total of approximately 1,157,000 square feet in Massachusetts, which is summarized as follows:

•800,000 square feet in Cambridge, MA, which is comprised of offices for our corporate headquarters and other administrative and development functions and laboratories, of which 289,000 square feet is subleased by multiple companies for general office space, laboratories and manufacturing facilities; and

•357,000 square feet of office space in Weston, MA, of which 174,000 square feet is subleased through the remaining term of our lease agreement.

Our Massachusetts lease agreements expire at various dates through the year 2028.

North Carolina

In RTP, NC we own approximately 1,040,000 square feet of real estate space, which is summarized as follows:

•357,000 square feet of laboratory and office space;

•206,000 square foot multi-purpose facility, including an ASO manufacturing suite and administrative space;

•175,000 square feet related to a large-scale biologics manufacturing facility;

•105,000 square feet related to a small-scale biologics manufacturing facility;

•84,000 square feet of warehouse space and utilities;

•70,000 square feet related to a parenteral fill-finish facility; and

•43,000 square feet related to a large-scale purification facility.

In addition, we lease approximately 65,000 square feet of warehouse space and 103,000 square feet of office space in Durham, NC. Our North Carolina lease agreements expire at various dates through the year 2031.

In March 2021 we announced our plans to build a new gene therapy manufacturing facility in RTP, NC to support our gene therapy pipeline across multiple therapeutic areas. The new facility will be 175,000 square feet and is expected to be operational by the end of 2023, with an estimated total investment of $200.0 million. Construction for this new facility began during the fourth quarter of 2021.

Switzerland

In order to support our future growth and drug development pipeline, we are building a large-scale biologics manufacturing facility in Solothurn, Switzerland. Upon completion, the facility will include 393,000 square feet related to a large-scale biologics manufacturing facility, 290,000 square feet of warehouse, utilities and support space and 51,000 square feet of administrative space. In the second quarter of 2021 a portion of the facility received a GMP multi-product license from SWISSMEDIC.

Other International

We lease office space in Baar, Switzerland, our international headquarters; the U.K.; Germany; France; Japan; Canada and numerous other countries. Our international lease agreements expire at various dates through the year 2031.

ITEM 3. LEGAL PROCEEDINGS

For a discussion of legal matters as of December 31, 2021, please read Note 20, Litigation, to our consolidated financial statements included in this report, which is incorporated into this item by reference.

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ITEM 4. MINE SAFETY DISCLOSURES

Not applicable.

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PART II

ITEM 5. MARKET FOR REGISTRANT'S COMMON EQUITY, RELATED STOCKHOLDER MATTERS AND ISSUER PURCHASES OF EQUITY SECURITIES

Market and Stockholder Information

Our common stock trades on The Nasdaq Global Select Market under the symbol “BIIB.” As of February 2, 2022, there were approximately 479 shareholders of record of our common stock.

Dividends

We have not paid cash dividends since our inception. While we historically have not paid cash dividends and do not have a current intention to pay cash dividends, we continually review our capital allocation strategies, including, among other things, payment of cash dividends, share repurchases and acquisitions.

Issuer Purchases of Equity Securities

The following table summarizes our common stock repurchase activity during the fourth quarter of 2021:

Total(1) — $ —

(1) There were no share repurchases during the fourth quarter of 2021.

In October 2020 our Board of Directors authorized a program to repurchase up to $5.0 billion of our common stock (2020 Share Repurchase Program). Our 2020 Share Repurchase Program does not have an expiration date. All share repurchases under our 2020 Share Repurchase Program will be retired. Under our 2020 Share Repurchase Program, we repurchased and retired approximately 6.0 million and 1.6 million shares of our common stock at a cost of approximately $1.8 billion and $400.0 million during the years ended December 31, 2021 and 2020, respectively. Approximately $2.8 billion remained available under our 2020 Share Repurchase Program as of December 31, 2021.

In December 2019 our Board of Directors authorized a program to repurchase up to $5.0 billion of our common stock (December 2019 Share Repurchase Program), which was completed as of September 30, 2020. All shares repurchased under our December 2019 Share Repurchase Program were retired. Under our December 2019 Share Repurchase Program, we repurchased and retired approximately 16.7 million shares of our common stock at a cost of approximately $5.0 billion during the year ended December 31, 2020.

In March 2019 our Board of Directors authorized a program to repurchase up to $5.0 billion of our common stock (March 2019 Share Repurchase Program), which was completed as of March 31, 2020. All shares repurchased under our March 2019 Share Repurchase Program were retired. Under our March 2019 Share Repurchase Program, we repurchased and retired approximately 4.1 million and 14.7 million shares of our common stock at a cost of approximately $1.3 billion and $3.7 billion during the years ended December 31, 2020 and 2019, respectively.

In August 2018 our Board of Directors authorized a program to repurchase up to $3.5 billion of our common stock (2018 Share Repurchase Program), which was completed as of June 30, 2019. All share repurchases under our 2018 Share Repurchase Program were retired. Under our 2018 Share Repurchase Program, we repurchased and retired approximately 8.9 million shares of our common stock at a cost of approximately $2.1 billion during the year ended December 31, 2019.

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Performance Graph

The performance graph below compares the five-year cumulative total stockholder return on our common stock, the Nasdaq Pharmaceutical Index, the S&P 500 Index and the Nasdaq Biotechnology Index.

On February 1, 2017, we completed the spin-off of our hemophilia business, Bioverativ Inc. (Bioverativ), as an independent, publicly traded company. In connection with the spin-off, each Biogen shareholder received one share of Bioverativ common stock for every two shares of Biogen common stock they owned. For additional information on the spin-off of our hemophilia business, please read Note 3, Hemophilia Spin-Off, to our consolidated financial statements included in our Annual Report on Form 10-K for the year ended December 31, 2018.

The performance graph below assumes the investment of $100.00 on December 31, 2016, in our common stock and each of the three indexes, with dividends being reinvested. Our stock prices have been adjusted for the effect of the spin-off of our hemophilia business. The five-year cumulative total stockholder return for Biogen does not reflect the reinvestment by Biogen shareholders of the distribution they received in connection with the spin-off of our hemophilia business or any subsequent increase or decrease in value of Bioverativ stock subsequent to the spin-off.

The stock price performance in the graph below is not necessarily indicative of future price performance.

The information included under the heading Performance Graph is “furnished” and not “filed” for purposes of Section 18 of the Securities Exchange Act, or otherwise subject to the liabilities of that section, nor shall it be deemed to be “soliciting material” subject to Regulation 14A or incorporated by reference in any filing under the Securities Act of 1933 or the Securities Exchange Act of 1934.

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ITEM 6. RESERVED

ITEM 7. MANAGEMENT'S DISCUSSION AND ANALYSIS OF FINANCIAL CONDITION AND RESULTS OF OPERATIONS

The following discussion should be read in conjunction with our consolidated financial statements and the accompanying notes beginning on page F-1 of this report.

For our discussion of the year ended December 31, 2020, compared to the year ended December 31, 2019, please read Item 7.Management's Discussion and Analysis of Financial Condition and Results of Operations located in our Annual Report on Form 10-K for the year ended December 31, 2020.

Executive Summary

Introduction

Biogen is a global biopharmaceutical company focused on discovering, developing and delivering worldwide innovative therapies for people living with serious neurological and neurodegenerative diseases as well as related therapeutic adjacencies. We have a leading portfolio of medicines to treat multiple sclerosis (MS), have introduced the first approved treatment for spinal muscular atrophy (SMA) and are providing the first and only approved treatment to address a defining pathology of Alzheimer’s disease. We also commercialize biosimilars of advanced biologics and focus on advancing our pipeline in neuroscience and specialized immunology. Lastly, we are focused on accelerating our efforts in digital health to support our commercial and pipeline programs while also creating opportunities for potential digital therapeutics. We support our drug discovery and development efforts through the commitment of significant resources to discovery, research and development programs and business development opportunities.

Our marketed products include TECFIDERA, VUMERITY, AVONEX, PLEGRIDY, TYSABRI and FAMPYRA for the treatment of MS; SPINRAZA for the treatment of SMA; ADUHELM for the treatment of Alzheimer's disease; and FUMADERM for the treatment of severe plaque psoriasis. We have certain business and financial rights with respect to RITUXAN for the treatment of non-Hodgkin's lymphoma, CLL and other conditions; RITUXAN HYCELA for the treatment of non-Hodgkin's lymphoma and CLL; GAZYVA for the treatment of CLL and follicular lymphoma; OCREVUS for the treatment of PPMS and RMS; and other potential anti-CD20 therapies, including mosunetuzumab, pursuant to our collaboration arrangements with Genentech, a wholly-

owned member of the Roche Group. For additional information on our collaboration arrangements with Genentech, please read Note 18, Collaborative and Other Relationships, to our consolidated financial statements included in this report.

Our innovative drug development and commercialization activities are complemented by our biosimilar business that expands access to medicines and reduces the cost burden for healthcare systems. Through our agreements with Samsung Bioepis, our joint venture with Samsung BioLogics, we market and sell BENEPALI, an etanercept biosimilar referencing ENBREL, IMRALDI, an adalimumab biosimilar referencing HUMIRA, and FLIXABI, an infliximab biosimilar referencing REMICADE, in certain countries in Europe. We have also secured the exclusive rights to commercialize BYOOVIZ, a ranibizumab biosimilar referencing LUCENTIS, which was approved in the U.S., the E.U. and the U.K. during the third quarter of 2021. For additional information on our collaboration arrangements with Samsung Bioepis, please read Note 18, Collaborative and Other Relationships, to our consolidated financial statements included in this report.

We seek to ensure an uninterrupted supply of medicines to patients around the world. To that end, we continually review our manufacturing capacity, capabilities, processes and facilities. In order to support our future growth and drug development pipeline, we are expanding our large molecule production capacity by building a large-scale biologics manufacturing facility in Solothurn, Switzerland. In the second quarter of 2021 a portion of the facility received a GMP multi-product license from SWISSMEDIC. We believe that the Solothurn facility will support our anticipated near-term needs for the manufacturing of ADUHELM and other biologic assets. In addition, we believe that the Solothurn site may provide us with the ability to further expand if we need additional large scale manufacturing capacity to support future clinical and commercial manufacturing requirements. If we are unable to fully utilize our manufacturing facilities, due to lower than forecasted demand for our products, we will incur excess capacity charges which will have a negative effect on our financial condition and results of operations.

Our revenue depends upon continued sales of our products as well as the financial rights we have in our anti-CD20 therapeutic programs, and, unless we develop, acquire rights to and/or commercialize new products and technologies, we will be substantially dependent on sales from our products and our financial rights in our anti-CD20 therapeutic programs for many years.

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In the longer term, our revenue growth will depend upon the successful clinical development, regulatory approval and launch of new commercial products as well as additional indications for our existing products, our ability to obtain and maintain patents and other rights related to our marketed products, assets originating from our research and development efforts and/or successful execution of external business development opportunities.

Business Environment

For a detailed discussion on our business environment, please read Item 1. Business, included in this report. For additional information on our competition and pricing risks that could negatively impact our product sales, please read Item 1A. Risk Factors, included in this report.

ADUHELM (aducanumab)

U.S.

In June 2021 the FDA granted accelerated approval of ADUHELM, which we are developing and commercializing in collaboration with Eisai, based on reduction in amyloid beta plaques observed in patients treated with ADUHELM. As part of the accelerated approval, we will conduct a confirmatory trial to verify the clinical benefit of ADUHELM in patients with Alzheimer’s disease. The FDA may withdraw approval if, among other things, the confirmatory trial fails to verify clinical benefit of ADUHELM, ADUHELM's benefit-risk is no longer positive or we fail to comply with the conditions of the accelerated approval.

The U.S. ADUHELM product label states that treatment with ADUHELM should be initiated in patients with mild cognitive impairment or mild dementia stage of disease, the population which was studied in clinical trials. We expect patient uptake will be gradual and we do not expect all eligible patients will be treated with ADUHELM for a variety of reasons, including appropriate patient selection criteria, a complex diagnostic and care pathway, the lack of readiness of healthcare providers and institutions to initiate treatment, concern regarding the accelerated approval of ADUHELM and its data and the ability to obtain and maintain adequate reimbursement for ADUHELM. In January 2022 the Centers for Medicare and Medicaid Services (CMS) released a proposed NCD decision memorandum, stating the proposed NCD would cover FDA approved monoclonal antibodies that target amyloid for the treatment of Alzheimer's disease for people with Medicare only if they are enrolled in qualifying clinical trials. We expect a final Medicare NCD by the second quarter of 2022, which should clarify Medicare reimbursement for the class of antibodies directed against amyloid. If the final

NCD is not broader than the proposed NCD, our future operating results may be negatively impacted.

Under our collaboration agreement with Eisai (ADUHELM Collaboration Agreement), we and Eisai will co-promote ADUHELM with a region-based profit split, with Eisai reimbursing us for 45.0% of development and commercialization costs incurred by the collaboration for the advancement of ADUHELM in the U.S. Shipments of ADUHELM commenced during the second quarter of 2021.

We have made, and may continue to make, commercial, medical and infrastructure investments in support of activities associated with the launch of ADUHELM in the U.S.

Rest of World

In October 2020 the EMA accepted for review the Marketing Authorization Application for aducanumab and in December 2020 the MHLW accepted for review the Japanese NDA for aducanumab.

In December 2021 the CHMP of the EMA adopted a negative opinion on the MAA for aducanumab in Europe. We are seeking a re-examination of the opinion by the CHMP.

If we do not receive regulatory approval or are unable to successfully commercialize aducanumab in other jurisdictions, our financial condition, business and operations may be adversely affected.

TECFIDERA

In 2020 U.S. federal courts in West Virginia and Delaware entered judgments in favor of the defendants in patent infringement proceedings relating to TECFIDERA Orange-Book listed patents. We appealed both decisions. In late 2021 the U.S. Court of Appeals for the Federal Circuit (Federal Circuit) affirmed the judgment of the West Virginia federal court. The appeals in the Delaware cases were stayed and we expect will remain so until the decision in the West Virginia case becomes final.

Multiple TECFIDERA generic entrants are now in the U.S. market and have deeply discounted prices compared to TECFIDERA. The generic competition for TECFIDERA has significantly reduced our TECFIDERA revenue and is expected to continue to have a substantial and increasing negative impact on our U.S. TECFIDERA revenue in the future.

In May 2021 the European General Court annulled the EMA's decision not to validate applications for approval of TECFIDERA generics on the basis that the EMA conducted the wrong assessment when determining TECFIDERA's entitlement to regulatory data and marketing protection. Our Company, the EMA and the EC have each appealed the General Court’s decision as wrongly decided and the appeal is pending.

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In November 2021 the CHMP of the EMA issued an ad hoc opinion referencing the General Court’s decision which concluded that "the totality of the available data cannot establish that [monoethyl fumarate] exerts a clinically relevant therapeutic contribution within FUMADERM." The EC will decide TECFIDERA’s entitlement to regulatory data and market protection. If data and market protection is not upheld, we could face generic competition in the E.U. as early as the first half of 2022, which would have an adverse impact on our TECFIDERA sales in the E.U. and our results of operations.

For additional information, please read the discussion under Results of Operations - Product Revenue - Multiple Sclerosis (MS) - Fumarate below.

Business Update Regarding COVID-19

The COVID-19 pandemic continues to present a substantial public health and economic challenge around the world. The length of time and full extent to which the COVID-19 pandemic directly or indirectly impacts our business, results of operations and financial condition, including sales, expense, reserves and allowances, the supply chain, manufacturing, clinical trials, research and development costs and employee-related costs, depends on future developments that are highly uncertain, subject to change and are difficult to predict, including as a result of new information that may emerge concerning COVID-19 and the actions taken to contain or treat COVID-19 as well as the economic impact on local, regional, national and international customers and markets.

We are monitoring the demand for our products, including the duration and degree to which we may see delays in starting new patients on a product due to hospitals diverting the resources that are necessary to administer certain of our products to care for COVID-19 patients, including products, such as TYSABRI and SPINRAZA, that are administered in a physician's office or hospital setting. We may also see reduced demand for immunosuppressant therapies during the COVID-19 pandemic.

While we are currently continuing the clinical trials we have underway in sites across the globe, COVID-19 precautions have impacted the timeline for some of our clinical trials and these precautions may, directly or indirectly, have a further impact on timing in the future. To help mitigate the impact of the COVID-19 pandemic to our clinical trials, we are pursuing innovative approaches such as remote monitoring, remote patient visits and supporting home infusions. These alternative measures have resulted in an immaterial increase to the cost of the clinical trials underway.

Factors such as the COVID-19 pandemic, adverse weather events, labor or raw material shortages and other supply chain disruptions could result in product shortages or other difficulties and delays in manufacturing our products.

For additional information on the various risks posed by the COVID-19 pandemic, please read Item 1A.Risk Factors included in this report.

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Financial Highlights

Diluted earnings per share attributable to Biogen Inc. were $10.40 for 2021, representing a decrease of 58.1% as compared to $24.80 in the same period in 2020.

As described below under Results of Operations, our net income and diluted earnings per share attributable to Biogen Inc. for the year ended December 31, 2021, compared to the year ended December 31, 2020, reflects the following:

Revenue

•Total revenue was $10,981.7 million for 2021, representing a $2,462.9 million, or 18.3%, decrease compared to $13,444.6 million in 2020.

•Product revenue, net totaled $8,846.9 million for 2021, representing a $1,845.3 million, or 17.3%, decrease compared to $10,692.2 million in 2020. This decrease was primarily due to a $1,735.4 million, or 22.2%, decrease in MS product revenue and a $147.0 million, or 7.2%, decrease in SPINRAZA product revenue, partially offset by a $35.3 million, or 4.4%, increase in revenue from our biosimilar business.

◦The decrease in MS product revenue was primarily due to a decrease in U.S. TECFIDERA demand as a result of multiple TECFIDERA generic entrants in the U.S. market.

◦The decrease in SPINRAZA revenue was primarily due to a decrease in demand as a result of increased competition in the U.S. and Germany as well as a decrease in pricing in the U.S. and rest of world markets, partially offset by an increase in sales volumes in Latin America and certain distributor markets.

•Revenue from anti-CD20 therapeutic programs totaled $1,658.5 million for 2021, representing a $319.3 million, or 16.1%, decrease compared to $1,977.8 million in 2020. This decrease was primarily due to a $480.2 million, or 45.5%, decrease in RITUXAN revenue, partially offset by a $146.3 million, or 17.3%, increase in royalty revenue on sales of OCREVUS. Sales of RITUXAN have been adversely affected by the onset of biosimilar competition.

•Other revenue totaled $476.3 million for 2021, representing a $298.3 million, or 38.5%, decrease from $774.6 million in 2020.

◦The decrease in other revenue was primarily due to higher contract manufacturing revenue in 2020, resulting from $346.2 million in revenue related to the delivery of the license for certain of our manufacturing-related intellectual property to a contract manufacturing customer.

Expense

•Total cost and expense was $8,141.0 million for 2021, representing a $753.5 million, or 8.5%, decrease compared to $8,894.5 million in 2020. This decrease was primarily due to a $1,489.7 million, or 37.3%, decrease in research and development expense.

◦The decrease in research and development expense was primarily due to $1,893.3 million in upfront payments recognized in 2020 in connection with our collaborations with Sangamo, Denali and Sage, partially offset by a $125.0 million upfront payment recognized in connection with our collaboration with InnoCare in 2021.

◦The decrease was partially offset by a $304.5 million, or 16.9%, increase in cost of sales, which was primarily driven by $164.0 million of charges associated with inventory and purchase commitments in excess of forecasted demand related to ADUHELM during 2021 as well as higher impairment charges recorded during 2021 as compared to 2020.

As described below under Financial Condition, Liquidity and Capital Resources:

•We generated $3,639.9 million of net cash flow from operations for 2021.

•Cash, cash equivalents and marketable securities totaled approximately $4,694.5 million as of December 31, 2021.

•We repurchased and retired approximately 6.0 million shares of our common stock at a cost of approximately $1.8 billion during 2021 under our 2020 Share Repurchase Program. Approximately $2.8 billion remained available under our 2020 Share Repurchase Program as of December 31, 2021.

Acquisitions, Collaborative and Other Relationships

For additional information on our acquisitions, collaborative and other relationships discussed below,

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please read Note 2, Acquisitions, Note 18, Collaborative and Other Relationships, and Note 19, Investments in Variable Interest Entities, to our consolidated financial statements included in this report.

Bio-Thera Solutions

In April 2021 we entered into a commercialization and license agreement to develop, manufacture and commercialize BAT1806, a Phase 3 clinical stage anti-interleukin-6 (IL-6) receptor monoclonal antibody that is a proposed biosimilar referencing ACTEMRA. In connection with this agreement, we made an upfront payment of $30.0 million to Bio-Thera Solutions.

InnoCare Pharma Limited

In July 2021 we entered into a collaboration and license agreement with InnoCare for orelabrutinib, an oral small molecule Bruton's tyrosine kinase inhibitor for the potential treatment of MS. In connection with this agreement, we made an upfront payment of $125.0 million to InnoCare.

For additional information on our collaboration arrangement with InnoCare, please read Note 18, Collaborative and Other Relationships, to our consolidated financial statements included in this report.

Mosunetuzumab

In January 2022 we exercised our option with Genentech to participate in the joint development and commercialization of mosunetuzumab, a late-stage bispecific antibody in development for B-cell non-Hodgkin’s lymphoma and other therapeutic areas. In connection with this exercise, we recorded a $30.0 million option exercise fee payable to Genentech in December 2021.

BIIB115 Option Exercise

In December 2021 we exercised our option with Ionis and obtained a worldwide, exclusive, royalty-bearing license to develop and commercialize BIIB115, a preclinical investigational ASO in development for SMA. In connection with this option exercise, we made an opt-in payment of $60.0 million to Ionis.

Samsung Bioepis - Biogen's Joint Venture with Samsung BioLogics

In January 2022 we entered into an agreement to sell to Samsung Biologics our equity in Samsung Bioepis. Under the terms of the proposed transaction, we would receive $1.0 billion in cash at closing and $1.3 billion to be deferred over two payments of $812.5 million due at the first anniversary and $437.5 million due at the second anniversary of the closing of the transaction. We would also be eligible

to receive up to an additional $50.0 million upon the achievement of certain commercial milestones.

Closing of the transaction is currently anticipated in mid-2022, contingent on the effectiveness of a securities registration statement filed by Samsung Biologics and satisfaction of certain regulatory and other customary closing conditions.

For additional information on the proposed transaction and our collaboration arrangements with Samsung Bioepis, please read Note 18, Collaborative and Other Relationships, to our consolidated financial statements included in this report.

Other Key Developments

Exchange Offer

In February 2021 we completed our Exchange Offer of our tendered 2045 Senior Notes for our 2051 Senior Notes and cash, and an offer to purchase our tendered 2045 Senior Notes for cash.

For additional information on our Exchange Offer, please read Note 12, Indebtedness, to our consolidated financial statements included in this report.

North Carolina Gene Therapy Manufacturing Facility

In March 2021 we announced our plans to build a new gene therapy manufacturing facility in RTP, NC to support our gene therapy pipeline across multiple therapeutic areas. The new facility will be 175,000 square feet and is expected to be operational by the end of 2023, with an estimated total investment of approximately $200.0 million. Construction for this new facility began during the fourth quarter of 2021.

Solothurn, Switzerland Manufacturing Facility

In May 2021 we announced that a portion of our Solothurn manufacturing facility received a GMP multi-product license from SWISSMEDIC.

For additional information on our Solothurn manufacturing facility, please read Note 10, Property, Plant and Equipment, to our consolidated financial statements included in this report.

BIIB125 (zuranolone)

In June 2021 we and Sage announced positive Phase 3 results for BIIB125 (zuranolone) for the potential treatment of MDD and PPD. In October 2021 we and Sage announced our plan to submit an NDA to the FDA for zuranolone in the second half of 2022, with rolling submission expected to start in early 2022. The planned initial submission package will seek approval of zuranolone for MDD, and an additional filing for PPD is anticipated in the first half of 2023.

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For additional information on our collaboration arrangement with Sage, please read Note 18, Collaborative and Other Relationships, to our consolidated financial statements included in this report.

Lecanemab (BAN2401)

In June 2021 the FDA granted Breakthrough Therapy designation for lecanemab, an anti-amyloid antibody for the potential treatment of Alzheimer's disease, which we are developing in collaboration with Eisai. In September 2021 Eisai initiated a rolling submission to the FDA of a BLA for lecanemab. The BLA is being submitted under the accelerated approval pathway and is primarily based on clinical, biomarker and safety data from the Phase 2b clinical trial in people with early Alzheimer's disease and confirmed amyloid pathology.

BYOOVIZ (ranibizumab-nuna)

In September 2021 we and Samsung Bioepis announced that the FDA has approved BYOOVIZ (ranibizumab-nuna), a biosimilar referencing LUCENTIS for the treatment of neovascular (wet) age-related macular degeneration, macular edema following retinal vein occlusion, and myopic choroidal neovascularization. In addition to the U.S. approval, BYOOVIZ was approved in the E.U. and the U.K. during the third quarter of 2021.

BIIB067 (tofersen)

In October 2021 we announced topline results from our pivotal Phase 3 VALOR study of BIIB067 (tofersen), an investigational antisense drug being evaluated for people with SOD1 ALS, indicating that the primary endpoint was not met. We are engaging with regulators and other key stakeholders to determine potential next steps.

RESULTS OF OPERATIONS

Revenue

Revenue is summarized as follows:

For the Years Ended December 31, % Change $ Change

Product revenue, net:

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Product Revenue

Product revenue is summarized as follows:

For the Years Ended December 31, % Change $ Change

Multiple Sclerosis (MS):

Spinal Muscular Atrophy:

Alzheimer's disease:

ADUHELM(3) 3.0 — — nm — 3.0 —

Biosimilars:

Other:

(1)Fumarate includes TECFIDERA and VUMERITY. VUMERITY became commercially available in the E.U. during the fourth quarter of 2021.

(2) Interferon includes AVONEX and PLEGRIDY.

(3) In June 2021 the FDA granted accelerated approval of ADUHELM, which became commercially available in the U.S. during the second quarter of 2021. For additional information, please read Note 18, Collaborative and Other Relationships - Eisai Co., Ltd. - ADUHELM Collaboration Agreement, to our consolidated financial statements included in this report.

nm Not meaningful

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Multiple Sclerosis (MS)

Fumarate

Fumarate revenue includes sales from TECFIDERA and VUMERITY. During the fourth quarter of 2021 VUMERITY was approved for the treatment of RRMS in the E.U., Switzerland and the U.K.

For 2021 compared to 2020, the 60.3% decrease in U.S. Fumarate revenue was primarily due to a decrease in TECFIDERA demand as a result of multiple TECFIDERA generic entrants entering the U.S. market. The decrease was partially offset by an increase in VUMERITY sales volumes in the U.S.

For 2021 compared to 2020, the 9.4% increase in rest of world Fumarate revenue was primarily due to an increase in TECFIDERA sales volumes of 6.2%.

In 2020 U.S. federal courts in West Virginia and Delaware entered judgments in favor of the defendants in patent infringement proceedings relating to TECFIDERA Orange-Book listed patents. We appealed both decisions. In late 2021 the Federal Circuit affirmed the judgment of the West Virginia federal court. The appeals in the Delaware cases were stayed and we expect will remain so until the decision in the West Virginia case becomes final.

Multiple TECFIDERA generic entrants are now in the U.S. market and have deeply discounted prices compared to TECFIDERA. The generic competition for TECFIDERA has significantly reduced our TECFIDERA revenue and is expected to continue to have a substantial and increasing negative impact on our U.S. TECFIDERA revenue in the future.

In May 2021 the European General Court annulled the EMA's decision not to validate applications for approval of TECFIDERA generics on the basis that the EMA conducted the wrong

assessment when determining TECFIDERA's entitlement to regulatory data and marketing protection. Our Company, the EMA and the EC have each appealed the General Court’s decision as wrongly decided and the appeal is pending.

In November 2021 the CHMP of the EMA issued an ad hoc opinion referencing the General Court’s decision which concluded that "the totality of the available data cannot establish that [monoethyl fumarate] exerts a clinically relevant therapeutic contribution within FUMADERM." The EC will decide TECFIDERA’s entitlement to regulatory data and market protection. If data and market protection is not upheld, we could face generic competition in the E.U. as early as the first half of 2022, which would have an adverse impact on our TECFIDERA sales in the E.U. and our results of operations.

For additional information, please read Note 20, Litigation, to our consolidated financial statements included in this report.

We expect that TECFIDERA revenue will continue to decline in 2022, compared to 2021, as a result of increasing generic competition.

We expect an increase in VUMERITY sales volumes in 2022, compared to 2021, mostly driven by demand growth, including the continued launch of VUMERITY in the E.U.

Interferon

For 2021 compared to 2020, the 22.8% decrease in U.S. Interferon revenue was primarily due to a decrease in Interferon sales volumes of 18.7%. The net decline in sales volumes reflects the continued decline of the Interferon market as patients transition to other higher efficacy and oral MS therapies.

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For 2021 compared to 2020, the 3.5% decrease in rest of world Interferon revenue was primarily due to a decrease in Interferon sales volumes of 3.8%.

We expect that Interferon revenue will continue to decline in both the U.S. and rest of world markets in 2022, compared to 2021, as a result of increasing competition from other MS products, including biosimilars, and further pricing reductions in certain European markets.

TYSABRI

For 2021 compared to 2020, the 4.1% increase in U.S. TYSABRI revenue was primarily due to an increase in pricing, partially offset by a decrease in sales volumes.

For 2021 compared to 2020, the 8.4% increase in rest of world TYSABRI revenue was primarily due to favorable volume impacts, partially offset by decreases in pricing.

We anticipate TYSABRI revenue to be relatively flat on a global basis in 2022, compared to 2021, despite increasing competition from additional treatments for MS. We expect to continue to face price reductions in certain European markets.

Spinal Muscular Atrophy

SPINRAZA

For 2021 compared to 2020, the 25.4% decrease in U.S. SPINRAZA revenue was primarily due to a decrease in sales volumes of 24.2%, resulting from increased competition.

For 2021 compared to 2020, the 4.2% increase in rest of world SPINRAZA revenue was primarily due to an increase in sales volumes, particularly in Latin America and certain distributor markets. These increases were offset by lower volumes resulting from increased competition in certain established markets, particularly Germany.

We face competition from a gene therapy product and an oral product. In 2022 we expect that SPINRAZA revenue will be subject to increased competition, likely resulting in continued patient discontinuations and a lower rate of new patient starts, combined with the impact of loading dose dynamics, as patients transition to dosing once every four months, and lower prices in certain rest of world countries.

For additional information on our collaboration arrangements with Ionis, please read Note 18, Collaborative and Other Relationships, to our consolidated financial statements included in this report.

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Alzheimer's Disease

ADUHELM

In June 2021 the FDA granted accelerated approval of ADUHELM, which became commercially available in the U.S. during the second quarter of 2021.

We expect minimal sales of ADUHELM in 2022.

For additional information on our collaboration arrangements with Eisai, please read Note 18, Collaborative and Other Relationships, to our consolidated financial statements included in this report.

Biosimilars

BENEPALI, IMRALDI and FLIXABI

During the third quarter of 2021 BYOOVIZ, a biosimilar referencing LUCENTIS, was approved in the U.S., the E.U and the U.K.

For 2021 compared to 2020, the 4.4% increase in biosimilar revenue was primarily due to the

favorable impact of higher volumes and foreign currency exchange, partially offset by decreases in pricing in certain markets.

We anticipate a slight decline in revenue from our biosimilars business in 2022 compared to 2021, despite the launch of BYOOVIZ in the U.S. and an anticipated modest increase in sales volume in 2022, as we continue to face price reductions in certain markets.

For additional information on our collaboration arrangements with Samsung Bioepis, please read Note 18, Collaborative and Other Relationships, to our consolidated financial statements included in this report.

Revenue from Anti-CD20 Therapeutic Programs

Genentech (Roche Group)

Our share of RITUXAN, including RITUXAN HYCELA, and GAZYVA collaboration operating profits in the U.S. and other revenue from anti-CD20 therapeutic programs are summarized in the table below. For purposes of this discussion, we refer to RITUXAN and RITUXAN HYCELA collectively as RITUXAN.

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Biogen’s Share of Pre-tax Profits in the U.S. for RITUXAN and GAZYVA

The following table provides a summary of amounts comprising our share of pre-tax profits in the U.S. for RITUXAN and GAZYVA:

For the Years Ended December 31,

For 2021 compared to 2020, the decrease in U.S. product revenue, net was primarily due to a decrease in sales volumes of RITUXAN in the U.S. of 38.8%, primarily due to the onset of competition from multiple biosimilar products.

For 2021 compared to 2020, product revenue, net also reflects an increase in GAZYVA sales volumes of 8.5%.

For 2021 compared to 2020, the decrease in collaboration cost and expense was primarily due to lower cost of sales, distribution costs and selling and marketing expense related to RITUXAN.

We are aware of several other anti-CD20 molecules, including biosimilar products, that have been approved and are competing with RITUXAN and GAZYVA in the oncology and other markets. In November 2019, January 2020 and January 2021 biosimilar products referencing RITUXAN were launched in the U.S. and are being offered at lower prices. This competition has had a significant adverse impact on the pre-tax profits of our collaboration

arrangements with Genentech, as the sales of RITUXAN have decreased substantially compared to prior periods. We expect that biosimilar competition will continue to increase as these products capture additional market share and that this will have a significant adverse impact on our co-promotion profits in the U.S. in future years.

Other Revenue from Anti-CD20 Therapeutic Programs

Other revenue from anti-CD20 therapeutic programs consist of royalty revenue on sales of OCREVUS and our share of pre-tax co-promotion profits from RITUXAN in Canada.

For 2021 compared to 2020, the increase in other revenue from anti-CD20 therapeutic programs was primarily due to sales growth of OCREVUS. Royalty revenue recognized on sales of OCREVUS for the years ended December 31, 2021, 2020 and 2019, totaled $991.7 million, $845.4 million and $687.5 million, respectively.

OCREVUS royalty revenue is 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 revenue will be adjusted for in the period in which they become known, which is generally expected to be the following quarter.

For additional information on our collaboration arrangements with Genentech, including information regarding the pre-tax profit-sharing formula and its impact on future revenue from anti-CD20 therapeutic programs, please read Note 18, Collaborative and Other Relationships, to our consolidated financial statements included in this report.

Other Revenue

Other revenue is summarized as follows:

For the Years Ended December 31, % Change $ Change

Revenue from Collaborative and Other Relationships

Revenue from collaborative and other relationships primarily includes royalty revenue on biosimilar products from Samsung Bioepis.

For additional information on our collaborative arrangements with Samsung Bioepis, please read Note 18, Collaborative and Other Relationships, to our

consolidated financial statements included in this report.

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Other Royalty and Corporate Revenue

We receive royalties from net sales on products related to patents that we have out-licensed and we record other corporate revenue primarily from amounts earned under contract manufacturing agreements.

For 2021 compared to 2020, the decrease in other corporate revenue was primarily due to higher contract manufacturing revenue during the year ended December 31, 2020, resulting from $346.2 million in revenue related to the delivery of the license for certain of our manufacturing-related intellectual property to a contract manufacturing customer. For additional information, please read Note 4, Revenue, to our consolidated financial statements included in this report.

Reserves for Discounts and Allowances

Revenue from product sales is recorded net of reserves established for applicable discounts and allowances, including those associated with the implementation of pricing actions in certain international markets where we operate.

These reserves are based on estimates of the amounts earned or to be claimed on the related sales and are classified as reductions of accounts receivable (if the amount is payable to our customer) or a liability (if the amount is payable to a party other than our customer). These estimates reflect our historical experience, current contractual and statutory requirements, specific known market events and trends, industry data and forecasted customer buying and payment patterns. Actual amounts may ultimately differ from our estimates. If actual results vary, we adjust these estimates, which could have an effect on earnings in the period of adjustment.

Reserves for discounts, contractual adjustments and returns that reduced gross product revenue are summarized as follows:

For the years ended December 31, 2021, 2020 and 2019, reserves for discounts and allowances as a percentage of gross product revenue were 28.6%, 27.1% and 24.3%, respectively.

Discounts

Discounts include trade term discounts and wholesaler incentives.

For 2021 compared to 2020, the decrease in discounts was primarily driven by a decrease in gross sales.

Contractual Adjustments

Contractual adjustments primarily relate to Medicaid and managed care rebates in the U.S., pharmacy rebates, co-payment (copay) assistance, Veterans Administration, 340B discounts, specialty pharmacy program fees and other government rebates or applicable allowances.

For 2021 compared to 2020, the decrease in contractual adjustments was primarily driven by lower TECFIDERA sales in the U.S., resulting in lower Medicaid, managed care and government rebates, partially offset by managed care rebates in the U.S. from VUMERITY sales.

Returns

Product return reserves are established for returns made by wholesalers. In accordance with contractual terms, wholesalers are permitted to return product for reasons such as damaged or expired product. The majority of wholesaler returns are due to product expiration. Provisions for product returns are

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recognized in the period the related revenue is recognized, resulting in a reduction to product sales.

For 2021 compared to 2020, return reserves were relatively consistent.

For additional information on our revenue reserves, please read Note 4, Revenue, to our consolidated financial statements included in this report.

Cost and Expense

A summary of total cost and expense is as follows:

For the Years Ended December 31, % Change $ Change

Acquired in-process research and development 18.0 75.0 — (76.0) nm (57.0) 75.0

Restructuring charges — — 1.5 nm nm — (1.5)

nm Not meaningful

Cost of Sales, Excluding Amortization and Impairment of Acquired Intangible Assets

Cost of sales, as a percentage of total revenue, were 19.2%, 13.4% and 13.6% for the years ended December 31, 2021, 2020 and 2019, respectively.

Product Cost of Sales

For 2021 compared to 2020, the increase in product cost of sales was primarily due to product mix and higher cost of sales associated with contract manufacturing agreements. The increase was also

due to the write-off of ADUHELM inventory during the year ended December 31, 2021, as discussed below.

Inventory amounts written down as a result of excess, obsolescence or unmarketability totaled $167.6 million, $26.6 million and $52.2 million for the years ended December 31, 2021, 2020 and 2019, respectively.

During the fourth quarter of 2021 we recorded approximately $164.0 million of charges associated with inventory and purchase commitments in excess of forecasted demand related to ADUHELM, which was recognized in cost of sales within our consolidated statements of income. In addition, we recognized the expected share of these charges from Eisai's 45.0% share in collaboration profit (loss) sharing within our consolidated statements of income. As of December 31, 2021, we had approximately $223.0 million of inventory related to ADUHELM. We may record additional write-downs of ADUHELM inventory if the final NCD is not broader than the proposed NCD.

For additional information, please read Note 18, Collaborative and Other Relationships, to our consolidated financial statements included in this report.

Royalty Cost of Sales

For 2021 compared to 2020, the increase in royalty cost of sales was primarily due to higher

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royalties payable on higher sales of TYSABRI and VUMERITY.

Research and Development

We support our drug discovery and development efforts through the commitment of significant resources to discovery, research and development programs and business development opportunities.

A significant amount of our research and development costs consist of indirect costs incurred in support of overall research and development activities and non-specific programs, including activities that benefit multiple programs, such as management costs, as well as depreciation, information technology and facility-based expenses. These costs are considered other research and

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development costs in the table above and are not allocated to a specific program or stage.

Research and development expense incurred in support of our marketed products includes costs associated with product lifecycle management activities including, if applicable, costs associated with the development of new indications for existing products. Late stage programs are programs in Phase 3 development or in registration stage. Early stage programs are programs in Phase 1 or Phase 2 development. Research and discovery represents costs incurred to support our discovery research and translational science efforts. Costs are reflected in the development stage based upon the program status when incurred. Therefore, the same program could be reflected in different development stages in the same year. For several of our programs, the research and development activities are part of our collaborative and other relationships. Our costs reflect our share of the total costs incurred.

For 2021 compared to 2020, the decrease in research and development expense was primarily due to approximately $1,084.0 million, $601.3 million and $208.0 million in upfront payments recognized upon the closing of our collaborations with Sage, Denali and Sangamo, respectively, in 2020. This decrease was partially offset by approximately $125.0 million in an upfront payment recognized upon the closing of our collaboration with InnoCare in the third quarter of 2021, the development of zuranolone for the potential treatment of MDD and PPD, the development of BIIB124 (SAGE-324) for the potential treatment of essential tremor, which we are developing in collaboration with Sage, and closeout costs associated with BIIB111 (timrepigene emparvovec) and BIIB112 (cotoretigene).

In 2021 we recorded upfront payments related to our new collaborations as part of research and development expense. Excluding upfront payments, we expect our core research and development expense to increase in 2022, driven by continued investment in our pipeline. We intend to continue committing significant resources to targeted research and development opportunities where there is a significant unmet need and where a drug candidate has the potential to be highly differentiated.

Milestone and Upfront Expense

Research and development expense for 2021 includes:

•$125.0 million charge to research and development expense in connection with the upfront payment associated with entering into our collaboration with InnoCare in the third quarter of 2021;

•$60.0 million charge to research and development expense upon the exercise of our option under our collaboration agreement with Ionis to develop and commercialize BIIB115, a preclinical investigational ASO in development for SMA;

•$30.0 million charge to research and development expense related to the option exercise fee payable to Genentech to jointly develop and commercialize mosunetuzumab, a late-stage bispecific antibody in development for B-cell non-Hodgkin's lymphoma and other therapeutic areas; and

•$30.0 million charge to research and development expense in connection with the upfront payment associated with entering into a commercialization and license agreement with Bio-Thera to develop, manufacture and commercialize BAT1806, a proposed biosimilar referencing ACTEMRA.

Research and development expense for 2020 includes:

•$1,084.0 million charge to research and development expense in connection with the upfront payment associated with entering into our collaboration with Sage in the fourth quarter of 2020;

•$601.3 million charge to research and development expense in connection with the upfront payment associated with entering into our collaboration with Denali in the third quarter of 2020; and

•$208.0 million charge to research and development expense in connection with the upfront payment associated with entering into our collaboration with Sangamo in the second quarter of 2020.

The upfront payments associated with these collaborations are classified as research and development expense as the programs they relate to had not achieved regulatory approval as of the payment date.

For additional information about these collaboration arrangements, please read Note 18, Collaborative and Other Relationships, to our consolidated financial statements included in this report.

Early Stage Programs

For 2021 compared to 2020, the decrease in spending related to our early stage programs was primarily due to a decrease in costs associated with:

•the discontinuation of opicinumab (anti-LINGO) in MS;

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•the discontinuation of BIIB054 (cinpanemab) in Parkinson's disease and the discontinuation of gosuranemab (BIIB092) in Alzheimer's disease;

•the advancement of dapirolizumab pego, an anti-CD40L pegylated Fab that we are developing in collaboration with UCB, for the potential treatment of SLE into late stage; and

•the advancement of BIIB059 (anti-BDCA2) for the potential treatment of SLE into late stage.

These decreases were partially offset by an increase in costs associated with:

•an increase in spending in the development of BIIB124 for the potential treatment of essential tremor;

•an increase in spending in the development of BIIB122 (DNL151) for the potential treatment of Parkinson's disease, which we are developing in collaboration with Denali; and

•an increase in spending in the development of BIIB135 (orelabrutinib) for the potential treatment of MS.

Late Stage Programs

For 2021 compared to 2020, the increase in spending associated with our late stage programs was primarily due to:

•an increase in spending in the development of zuranolone for the potential treatment of MDD and PPD;

•the advancement of dapirolizumab pegol for the potential treatment of SLE into late stage;

•the advancement of BIIB059 for the potential treatment of SLE into late stage;

•an increase in spending related to our option exercise with Genentech to jointly develop and commercialize mosunetuzumab, a late-stage bispecific antibody in development for B-cell non-Hodgkin's lymphoma and other therapeutic areas;

•an increase in spending related to lecanemab; and

•close out costs related to BIIB111.

These increases were partially offset by a decrease in costs associated with the advancement of ADUHELM from late stage to marketed.

Marketed Programs

For 2021 compared to 2020, the increase in spending associated with our marketed programs was primarily due to an increase in costs associated with:

•the advancement of ADUHELM from late stage to marketed upon the accelerated approval of ADUHELM in the U.S.

In March 2019 Eisai initiated a global Phase 3 trial for the development of lecanemab in early Alzheimer's disease. Under our collaboration arrangement, Eisai serves as the global operational and regulatory lead for lecanemab and all costs, including research, development, sales and marketing expense, are shared equally between us and Eisai.

For additional information on our collaboration arrangements with Eisai, please read Note 18, Collaborative and Other Relationships, to our consolidated financial statements included in this report.

Selling, General and Administrative

For 2021 compared to 2020, the increase in selling, general and administrative expense was primarily due to an increase in personnel in support of the launch of ADUHELM in the U.S. Beginning in the second quarter of 2021, reimbursement from Eisai for its share of U.S. ADUHELM selling, general and administrative expense is recognized in collaboration profit (loss) sharing in our consolidated statements of income.

In 2022 we expect selling, general and administrative costs to decrease as we plan to implement cost-reduction measures with a significant portion expected to be realized in 2022.

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Amortization and Impairment of Acquired Intangible Assets

Our amortization expense is based on the economic consumption and impairment of intangible assets. Our most significant amortizable intangible assets are related to our TYSABRI, AVONEX, SPINRAZA, VUMERITY and TECFIDERA (rest of world) products and other programs acquired through business combinations.

For the year ended December 31, 2021, amortization and impairment of acquired intangible assets reflects the impact of a $365.0 million impairment charge related to BIIB111, a $220.0 million impairment charge related to BIIB112 and a $44.3 million impairment charge related to vixotrigine (BIIB074) for the potential treatment of trigeminal neuralgia (TGN).

For the year ended December 31, 2020, amortization and impairment of acquired intangible assets reflects the impact of a $115.0 million impairment charge related to BIIB111, a $75.4 million impairment charge related to BIIB054 and a $19.3 million impairment charge related to one of our other IPR&D intangible assets.

Amortization of acquired intangible assets, excluding impairment charges, totaled $252.0 million, $255.1 million and $274.0 million for the years ended December 31, 2021, 2020 and 2019, respectively.

We monitor events and expectations regarding product performance. If new information indicates that the assumptions underlying our most recent analysis are substantially different than those utilized in our current estimates, our analysis would be updated and may result in a significant change in the anticipated lifetime revenue of the relevant products. The occurrence of an adverse event could substantially increase the amount of amortization expense related to our acquired intangible assets as compared to previous periods or our current expectations, which

may result in a significant negative impact on our future results of operations.

IPR&D Related to Business Combinations

IPR&D represents the fair value assigned to research and development assets that we acquired as part of a business combination and had not yet reached technological feasibility at the date of acquisition. We review amounts capitalized as acquired IPR&D for impairment annually, as of October 31, and whenever events or changes in circumstances indicate to us that the carrying value of the assets might not be recoverable.

Overall, the value of our acquired IPR&D assets is dependent upon several variables, including estimates of future revenue and the effects of competition, our ability to secure sufficient pricing in a competitive market, our ability to confirm safety and efficacy based on data from clinical trials and regulatory feedback, the level of anticipated development costs and the probability and timing of successfully advancing a particular research program from one clinical trial phase to the next. We are continually reevaluating our estimates concerning these and other variables, including our life cycle management strategies, research and development priorities and development risk, changes in program and portfolio economics and related impact of foreign currency exchange rates and economic trends and evaluating industry and company data regarding the productivity of clinical research and the development process. Changes in our estimates may result in a significant change to our valuation of our IPR&D assets.

Vixotrigine

In the periods since we acquired vixotrigine, there have been numerous delays in the initiation of Phase 3 studies for the potential treatment of TGN and for the potential treatment of diabetic painful neuropathy (DPN), another form of neuropathic pain. We have engaged with the FDA regarding the design of the Phase 3 studies of vixotrigine for the potential treatment of TGN and DPN and are now performing an additional clinical trial of vixotrigine.

The performance of this additional clinical trial delayed the initiation of the Phase 3 studies of vixotrigine for the potential treatment of TGN, and, as a result, we recognized an impairment charge of $44.3 million related to vixotrigine for the potential treatment of TGN during the first quarter of 2021. As of December 31, 2021, the carrying value associated with the remaining IPR&D asset for DPN was $132.7 million and the fair value of this asset was not significantly in excess of its carrying value.

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BIIB111 and BIIB112

During the fourth quarter of 2020 we recognized an impairment charge of $115.0 million related to BIIB111 as a result of third-party manufacturing delays that impacted the timing and increased the costs associated with advancing BIIB111 through Phase 3 development.

During the second quarter of 2021 we announced that our Phase 3 STAR study of BIIB111 and our Phase 2/3 XIRIUS study of BIIB112 did not meet their primary endpoints. In the third quarter of 2021 we suspended further development on these programs based on the decision by management as part of its strategic review process. For the year ended December 31, 2021, we recognized an impairment charge of $365.0 million related to BIIB111 and an impairment charge of $220.0 million related to BIIB112, reducing the remaining book values of these IPR&D intangible assets to zero.

In addition, for the year ended December 31, 2021, as a result of our decision to suspend further development of BIIB111 and BIIB112, we recognized charges of approximately $39.1 million related to our manufacturing arrangements and other costs that we expect to incur as a result of suspending these programs, which were recorded as research and development expense in our consolidated statements of income.

For additional information on the amortization and impairment of our acquired intangible assets, please read Note 6, Intangible Assets and Goodwill, to our consolidated financial statements included in this report.

Collaboration Profit (Loss) Sharing

Collaboration profit (loss) sharing primarily includes Samsung Bioepis' 50.0% share of the profit or loss related to our biosimilars commercial agreement with Samsung Bioepis and, beginning in the second quarter of 2021, Eisai's 45.0% share of

income and expense in the U.S. related to the ADUHELM Collaboration Agreement.

For the years ended December 31, 2021, 2020 and 2019 we recognized net profit-sharing expense of $285.4 million, $266.5 million and $241.6 million, respectively, to reflect Samsung Bioepis’ 50.0% sharing of the net collaboration profits.

For the year ended December 31, 2021, we recognized net profit-sharing income of $233.2 million to reflect Eisai's 45.0% share of loss related to the ADUHELM Collaboration Agreement. We also recognized net profit-sharing income of $45.0 million to reflect Eisai's 45.0% share of the $100.0 million milestone payment made to Neurimmune related to the launch of ADUHELM in the U.S.

For the year ended December 31, 2020, we recognized net profit-sharing income of $33.8 million to reflect Eisai's 45.0% share of the $75.0 million milestone payment made to Neurimmune related to the completed submission of the BLA for the approval of ADUHELM to the FDA.