OUR PURPOSE PIONEERING SCIENCE 116 BIOGEN 2021 YEAR IN REVIEW PATIENTS OUR PEOPLE ENVIRONMENT COMMUNITY REPORTING Board (SASB), the Task Force on Climate-related Financial Disclosures (TCFD) and the United Nations Sustainable Development Goals (SDGs). Biogen is a signatory of the United Nations Global Compact and in 2022 is an early adopter of the organization’s evolved reporting program. This report also is informed by the Biopharma Investor ESG Communications Guidance, which identifies ESG issues that are a high priority for the biopharmaceutical sector and recommends an approach to disclosure useful for investors. Biogen recognizes that ESG reporting expectations and standards are shifting, with anticipated updates to GRI Standards, the International Financial Reporting Standards Foundation’s announcement at COP26 of the International Sustainability Standards Board (ISSB), the work of the Value Reporting Foundation, and potential action by the U.S. Securities and Exchange Commission (SEC), among other developments. We are watching those developments with interest, and we remain deeply committed to continuous improvement. We will continue to listen to and learn from our stakeholders, deepening our understanding of the issues they care about as we bolster our ESG efforts and the ways we communicate about our progress and challenges. 2021 ESG materiality assessment Our methodology for assessing material ESG issues Biogen has regularly conducted ESG materiality assessments since 2009, and in 2021 we asked a broad range of stakeholders to share their priorities, their expectations of us and their views on our performance on 27 ESG issues. As part of the process, we invited input on an expanded range of issues, from our core business to the broader health system, seeking to understand where stakeholders see us exceeding expectations and where they see opportunities for us to strengthen our performance. IN 2021, BIOGEN CONSULTED WITH THE FOLLOWING STAKEHOLDERS Employees Researchers Competitors Industry associations Rating organizations Healthcare professionals Patient Advocacy Groups Suppliers Investors NGOs 3,000 external 2,000 internal ENGAGEMENT OF STAKEHOLDERS