OUR PURPOSE PIONEERING SCIENCE PATIENTS OUR PEOPLE ENVIRONMENT COMMUNITY REPORTING 16 BIOGEN 2021 YEAR IN REVIEW PIONEERING SCIENCE Driving innovation to defeat the most complex and devastating diseases EXECUTIVE SUMMARY WORKING AT THE FRONTIERS OF NEUROSCIENCE Leadership in neuroscience requires a pioneering spirit and a fearless commitment. Since our founding in 1978, Biogen has embraced this mindset to deliver breakthroughs in some of the world’s most intractable neurological diseases, including multiple sclerosis (MS), spinal muscular atrophy (SMA), Alzheimer’s disease and more. Diseases of the brain and central nervous system are complex and devastating – not only to the people directly impacted by them, but also to their loved ones, communities and the health systems that support us. Through investment in research and development, Biogen has brought new treatments forward while continuing to focus on areas of significant unmet need. Neuroscience is at an inflection point. For decades, we focused on understanding and treating disease. We now know that by the time patients with neurodegenerative disease become symptomatic, the underlying disease biology has been progressing for many years, even decades. This is why Biogen is advancing novel therapeutic approaches that seek to identify and address risk factors before symptoms appear. With a robust clinical pipeline and expanding portfolio, we remain dedicated to advancing pioneering treatments across neurology, biosimilars, specialized immunology and digital health. In 2021, we positioned Biogen to attain the most diversified pipeline in the company’s history by 2022, including more than 30 clinical programs across a broad set of disease areas and modalities, 10 of which are in Phase 3 or filed. This achievement reflects our innovative research and more than 30 business development agreements in the past five years, spanning a range of disease areas including MS, depression, stroke and ALS. In 2022, we expect a total of four data readouts, two of which are in Phase 3. Our scientific progress is guided by Biogen’s focus on patients and unwavering commitment to scientific integrity. As pioneers in neuroscience, we will continue to propel the industry forward, guided by our purpose to serve humanity through science. Enhancing our strategic portfolio True to our purpose and mission, we are continuing to advance breakthrough science that addresses significant unmet needs. We’re committed to investments, collaboration and research in pursuit of treatments for some of humanity’s most complex and devastating diseases. Progressing our diverse early- and late-stage neuroscience pipeline, in 2021 we had approximately 30 active clinical programs and are excited by the possibility of bringing new treatment options to people in need. We are pursuing a strategic plan that leverages our core competencies in neurology and in related growth areas. Our work is based on four strategic pillars to drive growth and value creation over the medium to long term: neurology, specialized immunology, biosimilars and digital health. Neurology Every day we work fearlessly to improve patients’ lives by offering therapies that may slow or halt the progression of neurological diseases. Our resolute dedication to addressing these devastating diseases has positioned us as a leader in the industry for developing therapies for MS and SMA. It has also paved the way for the U.S. Food and Drug Administration’s approval of ADUHELM®