BIOGEN INC.

Previous wording

LEQEMBI is in the early stages of commercial launch in the U.S. and certain international markets and SKYCLARYS is in the early stages of commercial launch in certain European markets. In addition to risks associated with new product launches and the other factors described in these Risk Factors, Biogen’s and Eisai’s ability to successfully commercialize LEQEMBI and our ability to successfully commercialize SKYCLARYS may be adversely affected due to:

Current wording

We have many products in the stages of ongoing commercial launch in the U.S. and certain international markets. LEQEMBI continues to expand its commercial presence in the U.S. and certain international markets and SKYCLARYS is in the early stages of commercial launch in certain European markets. In addition to risks associated with new product launches and the other factors described in these Risk Factors, Biogen’s and Eisai’s ability to successfully commercialize LEQEMBI and our ability to successfully commercialize SKYCLARYS may be adversely affected due to:

Previous wording

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. For example, we recently announced that we have entered into a definitive agreement to acquire Apellis. Our ability to realize the anticipated benefits of the potential acquisition depends on, among other things, our ability to complete the transaction in a timely manner or at all, and how efficiently and effectively we are able to integrate Apellis’ operations into ours and to commercialize EMPAVELI and SYFOVRE.

Current wording

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. For example, in May 2026, we completed our acquisition of Apellis, which became a wholly-owned subsidiary. Our ability to realize the anticipated benefits of the acquisition depends on, among other things, how efficiently and effectively we are able to integrate Apellis’ operations into ours and to commercialize EMPAVELI and SYFOVRE.

Previous wording

There is also significant economic pressure on state budgets, that may result in states increasingly seeking to achieve budget savings through mechanisms that limit coverage or payment for our drugs. 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 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.

Current wording

There is also significant economic pressure on state budgets, and certain states are increasingly seeking to achieve budget savings through mechanisms that limit coverage or payment for our drugs. Some states have adopted or 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 also 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 which may adversely affect our business and financial condition.

Previous wording

Cybersecurity threats and incidents are increasing in their frequency, sophistication and intensity, and are becoming increasingly difficult to detect, particularly when they impact vendors, customers or suppliers, and other companies in our supply chain. Cybersecurity threats and incidents are often carried out by motivated, well-resourced, skilled and persistent threat actors, including nation states, organized crime groups, “hacktivists” and may include or target employees or contractors acting with careless or malicious intent. Recent developments in the threat landscape include use of adversarial AI techniques, including generative AI models and machine learning, as well as an increased number of cyber extortion attacks, with higher financial ransom demand amounts and increasing sophistication and variety of ransomware techniques and methodology. AI technologies, including generative AI models and machine learning, develop rapidly and threat actors use them to identify currently unknown vulnerabilities and create new sophisticated attack methods that are increasingly automated, targeted, coordinated and more difficult to defend against. This may necessitate ongoing enhancements to our cybersecurity systems and infrastructure. Geopolitical instability may increase the risk of cybersecurity threats. Cybersecurity threats or incidents may 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 information systems and data. Cybersecurity threats and incidents 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 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.

Current wording

Cybersecurity threats and incidents are increasing in their frequency, sophistication and intensity, and are becoming increasingly difficult to detect, particularly when they impact employees, vendors, customers or suppliers, and other companies in our supply chain. Cybersecurity threats and incidents are often carried out by motivated, well-resourced, skilled and persistent threat actors, including nation states, organized crime groups, “hacktivists” and may include or target employees or contractors acting with careless or malicious intent. Recent developments in the threat landscape include use of adversarial AI techniques, including generative AI models and machine learning, as well as an increased number of cyber extortion attacks, with higher financial ransom demand amounts and increasing sophistication and variety of ransomware techniques and methodology. AI technologies, including generative AI models and machine learning, develop rapidly and threat actors use them to identify currently unknown vulnerabilities and create new sophisticated attack methods that are increasingly automated, targeted, coordinated and more difficult to defend against. This may necessitate ongoing enhancements to our cybersecurity systems and infrastructure. Geopolitical instability may increase the risk of cybersecurity threats. Cybersecurity threats or incidents may 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 information systems and data. Cybersecurity threats and incidents 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 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.

Previous wording

Our success is dependent upon our ability to attract and retain qualified management and other 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, integration related to the pending acquisition of Apellis, the underperformance or discontinuation of one or more marketed, preclinical or clinical programs, recruitment by competitors or changes in the overall labor market. Changes in our organizational structure or in our flexible working arrangements could also impact 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.

Current wording

Our success is dependent upon our ability to attract and retain qualified management and other 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, integration of acquired businesses, assets or operations, the underperformance or discontinuation of one or more marketed, preclinical or clinical programs, recruitment by competitors or changes in the overall labor market. Changes in our organizational structure or in our flexible working arrangements could also impact 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.

Previous wording

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, debt refinancing, 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 which could significantly increase our financing costs. 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.

Current wording

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, debt refinancing, 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 lead to uncertainty and liquidity issues for both borrowers and investors. Recent and potential disruptions, including those related to tariff announcements and trade policy uncertainty, may exacerbate these conditions. In the event of adverse conditions, we may be unable to obtain capital or credit market financing on favorable terms which could significantly increase our financing costs. 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.

Previous wording

As a global 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, 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, especially in the U.S. (including the OBBBA) and Switzerland, and regulations either prospectively or retrospectively and the effects of the integrations of Reata and HI-Bio. Our estimates concerning the impact of the OBBBA remain subject to developing interpretations of the provisions of the OBBBA, which may require further adjustments and changes in our estimates, and could have a material adverse effect on our business.

Current wording

As a global 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, 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, especially in the U.S. (including the OBBBA) and Switzerland, and regulations either prospectively or retrospectively and the effects of the integrations of acquired businesses. Our estimates concerning the impact of the OBBBA remain subject to developing interpretations of the provisions of the OBBBA, which may require further adjustments and changes in our estimates, and could have a material adverse effect on our business.

Previous wording

The following table summarizes our common stock repurchase activity under our 2020 Share Repurchase Program during the first quarter of 2026:

Current wording

The following table summarizes our common stock repurchase activity under our 2020 Share Repurchase Program during the second quarter of 2026:

Previous wording

(1)There were no share repurchases during the first quarter of 2026.

Current wording

(1)There were no share repurchases during the second quarter of 2026.

Previous wording

From time to time, our officers (as defined in Rule 16a-1(f)) and directors may enter into, amend or terminate Rule 10b5-1 ornon-Rule 10b5-1 trading arrangements (as each such term is defined in Item 408 of Regulation S-K). During the first quarter of 2026 there were no trading arrangements for the purchase or sale of our securities entered into, amended or terminated by our officers and directors.

Current wording

From time to time, our officers (as defined in Rule 16a-1(f)) and directors may enter into, amend or terminate Rule 10b5-1 ornon-Rule 10b5-1 trading arrangements (as each such term is defined in Item 408 of Regulation S-K). During the second quarter of 2026, our officers and directors took the following actions with respect to trading arrangements: