Disease Areas
Alzheimer’s disease, the most common form of dementia, is a progressive neurological disease that affects memory, thinking and independence. Today, more than 55 million people worldwide are living with dementia, with Alzheimer’s disease accounting for an estimated 60–70% of cases.1
The onset and progression of Alzheimer’s disease involve complex biology and multiple pathological drivers, including amyloid beta and tau proteins.2
Amyloid beta can accumulate in the brain and form plaques that are believed to contribute to the disease process.2 Tau proteins normally help support healthy neuron function. Neurons transmit information throughout the body but when they become abnormal with a buildup of beta-amyloid plaques outside the neuron and tau protein tangles inside the neuron, the transmissions are blocked and can contribute to neurodegeneration and cognitive decline.3
Alzheimer’s disease is usually diagnosed in people aged 65 years and older, but it may start earlier, with subtle neurological changes occurring years or even decades before symptoms appear. Many people may experience early, often unrecognized signs of mild cognitive impairment before receiving a diagnosis.
Driven by our commitment to patients and our deep expertise in neuroscience, we are advancing Alzheimer’s disease innovation by relentlessly following the science and targeting key drivers of the disease. We aim to help address unmet needs in this devastating condition, with an emphasis on earlier diagnosis, intervention and treatment.
Amyloid pathology can begin decades before symptoms appear and may contribute to downstream tau pathology, which is thought to be closely linked to neuronal dysfunction and clinical decline.3,4 Recognizing this complexity, we believe advancing innovation in Alzheimer’s disease will require personalized, multimodal approaches that address multiple drivers of disease biology.
We understand how incredibly challenging it is to treat this complex and progressive condition, which is why we will never stop innovating for patients, families and providers in the Alzheimer’s disease community.
We are advancing research to support earlier diagnosis through blood-based biomarkers and investigating therapies directed at key drivers of Alzheimer’s disease biology, including amyloid and tau. By deepening our understanding of these distinct but interconnected pathways, we aim to help address the complexity of Alzheimer’s disease and advance innovation across the disease continuum.
We are currently conducting clinical trials to evaluate the efficacy and safety of investigational drugs in our pipeline for people living with Alzheimer’s disease.
Lance had noticed changes in his memory long before he received an Alzheimer’s disease diagnosis. Forgetting appointments and details at work felt unsettling at first, but seeing the word ‘Alzheimer’s’ in his test results took his breath away. Lance speaks openly about the emotional reality of his diagnosis and the importance of living fully in the present.
Alzheimer’s disease is primarily characterized by changes in both amyloid and tau proteins. This video explores how these hallmarks of disease develop over time and how tau tangles are associated with neuronal dysfunction, brain atrophy, and the progression of symptoms.
Deciding to participate in a clinical trial requires careful consideration. In most cases, the drugs investigated in clinical trials are not yet approved by regulatory agencies like the Food and Drug Administration (FDA) in the United States. The benefits and risks of taking the treatment are not completely known. By volunteering for a clinical trial, you are helping the medical community determine whether new treatments are safe and effective.
Learn more about clinical trials
View all recruiting Alzheimer’s disease clinical trials
For additional questions, contact our Patient Center at patientcenter@biogen.com
Biogen has signed agreements with the National Association of Free and Charitable Clinics (NAFC), which is focused on addressing health disparities and access. NAFC has a large network of clinics across the country, with teams that will provide appropriate information and education about Alzheimer’s disease and support cognitive screening.
Biogen’s commitment to health equity is rooted in efforts focused on providing culturally competent resources and care, offering cognitive testing, engaging with community health centers and, when possible, mitigating out-of-pocket costs for patients and families.
Alzheimer's disease is the most common cause of dementia, accounting for an estimated 60–70% of cases worldwide.1
1 in 3 seniors dies with Alzheimer's or another dementia.5.
More than 80% of Americans know little or are not familiar with mild cognitive impairment (MCI), which can be an early stage of Alzheimer’s.6
1. World Health Organization, “Dementia.” Dementia, World Health Organization, 2025, https://www.who.int/news-room/fact-sheets/detail/dementia.
2. Ratan, Y., Rajput, A., Maleysm, S., Pareek, A., Jain, V., Pareek, A., Kaur, R., & Singh, G. (2023). An Insight into Cellular and Molecular Mechanisms Underlying the Pathogenesis of Neurodegeneration in Alzheimer's Disease. Biomedicines, 11(5), 1398. https://doi.org/10.3390/biomedicines11051398
3. Mietelska-Porowska, A., Wasik, U., Goras, M., Filipek, A., & Niewiadomska, G. (2014). Tau protein modifications and interactions: their role in function and dysfunction. International journal of molecular sciences, 15(3), 4671–4713. https://doi.org/10.3390/ijms15034671
4. Scheltens, P., De Strooper, B., Kivipelto, M., Holstege, H., Chételat, G., Teunissen, C. E., Cummings, J., & van der Flier, W. M. (2021). Alzheimer's disease. Lancet (London, England), 397(10284), 1577–1590. https://doi.org/10.1016/S0140-6736(20)32205-4
5. Alzheimer’s Disease facts and figures. Alzheimer’s Association. https://www.alz.org/alzheimers-dementia/facts-figures
6. Alzheimer’s Association, “Mild Cognitive Impairment (MCI).” Mild Cognitive Impairment (MCI), Alzheimer’s Association, 2023, https://www.alz.org/alzheimers-dementia/what-is-dementia/related_conditions/mild-cognitive-impairment.