Alzheimer's disease drugs

• ClinicalTrials.gov lists 1,646 ¹ interventional drug or biologic studies in Alzheimer's disease; 280 ² are active and 332 ³ are Phase 3.
• 269 ⁴ started between January 2023 and September 2026: 128 ⁵ with a US site and 46 ⁶ with a China site.
• Annual starts were 87 ⁷ in 2021 and 78 ⁸ in 2025, a flat trend despite two approvals.
• Anti-amyloid antibodies appear in 21 ⁹ of the studies started since 2023.

Alzheimer's drug trial starts were 66 ¹⁰ in 2020, 87 ⁷ in 2021 and 81 ¹¹ in 2022. They dipped to 58 ¹² in 2023 and recovered only to 78 ⁸ in 2025. That is unlike oncology and metabolic tracks, where approvals were followed by fast growth.

The United States hosts most studies: 34 ¹³ of the 2025 starts had a US site, compared with 16 ¹⁴ with a China site. China's share is rising slowly, helped by blood-biomarker programmes and domestic companies. Industry sponsorship has fallen as a share of new studies, while academic groups and prevention networks carry more of the work.

Anti-amyloid antibodies appear in 21 ⁹ studies started since 2023. Most are extensions, new populations or new formulations of approved drugs. Lecanemab appears in 9 ²⁶ and donanemab in 8 ²⁷. Roche's trontinemab, which uses a transferrin-receptor "brain shuttle" to raise brain exposure, appears in 2 ²⁸. It is now in Phase 3, including a study started in 2026 in cognitively unimpaired people at risk of the disease.

Tau-targeted therapies appear in 6 ²⁹ new studies, including antisense oligonucleotides that lower tau production. GLP-1 receptor agonists appear in 5 ³⁰. Novo Nordisk reported on 24 November 2025 that its two Phase 3 semaglutide studies in early Alzheimer's disease, evoke and evoke+, did not meet their primary endpoint (Novo Nordisk), which cools this line of work.

Neuropsychiatric symptoms, such as agitation and psychosis, are a separate and more tractable market. Drugs aimed at them appear in 7 ³¹ new studies.

• Kisunla (donanemab), approved 2 July 2024 (BLA 761248)
• Leqembi (lecanemab), 6 January 2023 (BLA 761269)
• Aduhelm (aducanumab), 7 June 2021 (BLA 761178); Biogen announced its discontinuation in January 2024 (Biogen)

The approved antibodies slow decline modestly and need amyloid confirmation, infusion or injection and MRI monitoring for amyloid-related imaging abnormalities. Those practical burdens, more than efficacy alone, limit uptake and define what a better drug must fix.

• Solve a practical problem of the approved drugs. Examples are lower ARIA risk, subcutaneous or less frequent dosing, and better brain penetration. These are clearer goals than a new mechanism with an unproven link to cognition.
• Use blood biomarkers to cut trial cost. Plasma p-tau assays make screening cheaper and enable prevention trials. Companies that design trials around them can move faster.
• Treat symptom drugs as a separate business. Agitation, psychosis and sleep in dementia have shorter trials and clearer endpoints than disease modification.
• Expect a high failure rate. Of the tracks in this series, Alzheimer's has the most studies stopped for lack of efficacy. Stage-gate funding and early human biomarker evidence of target engagement are essential.

Every trial count is the totalCount of one ClinicalTrials.gov API v2 query, retrieved on 26 September 2026. Each numbered citation opens a record whose source link re-runs the query. The track includes interventional studies in Alzheimer's disease with a drug or biologic intervention. It therefore includes some diagnostic radiotracer studies and repurposed generic drugs.

Mechanism bars match intervention names and are restricted to Alzheimer's studies. They are small numbers and can move with a few registrations. The comparison of efficacy-related stops across tracks comes from a review of the stop reasons recorded in the registry and is not a separate published statistic. Semaglutide trial results and product discontinuations come from company announcements. Approval dates come from Drugs@FDA.