Clinical Trials for Alzheimer’s Disease: Drug Studies and How to Enroll

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Alzheimer’s disease research has entered a productive period. Since 2021, the FDA has cleared anti-amyloid antibody therapies, and the approvals of lecanemab (Leqembi) and donanemab (Kisunla) established that these treatments can modestly slow decline in early Alzheimer’s. Behind them sits a large pipeline of next-generation amyloid therapies, tau-targeted approaches, anti-inflammatory agents, and combinations. For people with early-stage Alzheimer’s or mild cognitive impairment, clinical trials for alzheimers can offer a way to access investigational therapies and contribute to research. This guide explains what trials are, how they are structured, where to search, and what informed participation involves. It is educational and is not a substitute for advice from your own doctor.

What a Clinical Trial Is

A clinical trial is a research study that tests whether a treatment, device, or strategy is safe and effective in people. Trials follow a detailed written plan (a protocol) and are reviewed by an institutional review board that oversees participant safety. Joining a trial is participating in research, which is not the same as receiving proven treatment: an investigational therapy may turn out to help, to make no difference, or to have side effects, and some participants receive a placebo. That uncertainty is the reason trials exist.

The Phases of a Trial

Drug trials generally move through four phases:

• Phase 1 tests safety, dosing, and side effects in a small group.
• Phase 2 looks at whether the treatment appears to work and continues to monitor safety in a larger group.
• Phase 3 compares the treatment against a placebo or standard care in a large group to confirm effectiveness and watch for less common side effects; positive phase 3 results often support FDA approval.
• Phase 4 studies happen after approval to track long-term safety and real-world use.

Knowing the phase helps set expectations. Early-phase trials focus more on safety than on benefit, while later-phase trials test treatments that already have preliminary evidence behind them.

Categories of Alzheimer’s Trials

Active Alzheimer’s trials in 2026 span several approaches:

Next-generation anti-amyloid therapies: Building on lecanemab and donanemab, trials test more potent antibodies, potential oral amyloid-targeted therapies, and combinations with anti-tau approaches.

Anti-tau therapies: Because tau pathology tracks closely with cognitive decline, trials test anti-tau antibodies, small molecules, and antisense oligonucleotides that reduce tau production.

Anti-inflammatory approaches: Trials test agents targeting microglial inflammation, complement pathways, and other immune-modulating strategies.

Synaptic and neuroprotective agents: Drugs aimed at preserving synaptic function and slowing neurodegeneration.

Lifestyle and prevention trials: Studies in cognitively healthy at-risk adults testing whether multidomain interventions (exercise, blood pressure control, cognitive engagement) delay or prevent onset.

Combination trials: Anti-amyloid plus anti-tau, or anti-amyloid plus other mechanisms.

Where to Find Alzheimer’s Trials

Reliable starting points include:

• ClinicalTrials.gov, the US government registry of trials worldwide, where you can search by condition and location.
• The NIA’s Alzheimers.gov Clinical Trials Finder, a plain-language federal tool for finding Alzheimer’s and dementia studies.
• Alzheimer’s Association TrialMatch, a free matching service for Alzheimer’s and dementia trials.
• NIH-funded Alzheimer’s Disease Research Centers (ADRCs) at academic medical centers across the US.
• Memory disorders and neurology programs at major academic centers.

Whichever route you use, discuss any trial with your own neurologist or primary doctor before enrolling, so it fits with your overall care.

Informed Consent and Your Right to Withdraw

Informed consent is the heart of ethical research. Before you enroll, the study team must explain the purpose, procedures, likely time commitment, potential risks and benefits, and alternatives, and they must give you time and space to ask questions. According to the National Institute on Aging, participation is voluntary, and you can withdraw at any time, for any reason, without penalty or loss of the care you would otherwise receive.

Because Alzheimer’s can affect memory and decision-making, many trials involve a study partner, often a spouse, adult child, or close friend, who attends visits and helps report on daily function. If a person’s capacity to consent is reduced, a legally authorized representative (such as a healthcare proxy or someone designated under state law) may provide proxy consent, ideally alongside the participant’s own assent and in line with the person’s previously expressed wishes. These safeguards exist to protect participants, and the NIA’s ADEAR Center (1-800-438-4380) can answer questions about participating.

How Trials Are Organized by Disease Stage

Preclinical Alzheimer’s: Cognitively normal adults with biomarker evidence of disease. Prevention trials test whether early intervention can delay symptoms.

Mild cognitive impairment (MCI): Cognitive complaints with documented testing changes but preserved daily function; many disease-modifying trials enroll here.

Mild Alzheimer’s dementia: Diagnosed Alzheimer’s with mild functional impairment. The approved anti-amyloid therapies are used at this stage.

Moderate Alzheimer’s dementia: Symptomatic therapies such as donepezil and memantine are standard; disease-modifying trials are less common.

Severe Alzheimer’s: Trials focus on supportive care, symptom management, and caregiving.

Biomarker-Confirmed Eligibility

Modern disease-modifying trials generally require biomarker confirmation of Alzheimer’s pathology, not just a clinical diagnosis. Standard confirmations include amyloid PET imaging, cerebrospinal fluid analysis, and, increasingly, blood-based biomarkers such as plasma p-tau. This matters because a clinical diagnosis without biomarker confirmation is wrong a meaningful fraction of the time; some people turn out to have other causes of dementia (vascular, Lewy body, frontotemporal) that look similar.

Typical Eligibility Criteria

Common inclusion criteria for disease-modifying trials:

• MCI due to Alzheimer’s or mild Alzheimer’s dementia
• Age range commonly around 50 to 85
• Biomarker confirmation of Alzheimer’s pathology
• Stable use of any cholinesterase inhibitor or memantine for a specified period
• A study partner who attends visits and provides functional assessment
• Enough cognitive and functional capacity to comply with study procedures

Common exclusion criteria include significant other neurological disease, some cardiovascular conditions, active cancer, and, for anti-amyloid studies, factors that raise bleeding or ARIA risk such as anticoagulation or certain genetic profiles.

The ARIA Monitoring Requirement

Anti-amyloid therapies can cause amyloid-related imaging abnormalities (ARIA), which are areas of brain swelling (ARIA-E) or small bleeds (ARIA-H) seen on MRI. ARIA is often asymptomatic but can occasionally cause serious problems. Because of this, both trials and approved anti-amyloid treatment require baseline and periodic MRI monitoring, and often APOE genetic testing, since APOE4 carriers face higher ARIA risk. This is one reason these drugs are prescriber-managed rather than routine.

What Participation Involves

• A comprehensive baseline workup, including cognitive testing, brain MRI, and often amyloid PET or CSF analysis
• Treatment with the investigational therapy (often IV infusions every few weeks for antibodies, or daily oral dosing for small molecules)
• Regular cognitive testing, typically every few months
• Frequent safety MRIs for anti-amyloid trials
• Functional and quality-of-life assessments with study-partner input
• Follow-up commonly lasting 18 to 24 months or longer

Approved Anti-Amyloid Drugs Are Prescriber-Managed

Lecanemab (Leqembi) and donanemab (Kisunla) are FDA-approved for early Alzheimer’s and are prescribed and monitored by clinicians, with the MRI surveillance for ARIA described above. Lecanemab is also available in a subcutaneous form for parts of the treatment course. By contrast, aducanumab (Aduhelm), the first drug in this class, was discontinued by its manufacturer in 2024 as the company shifted resources, not because of a new safety finding. Do not stop your current medications to join a trial or to start any of these therapies without your doctor’s guidance.

Frequently Asked Questions

Do I need a confirmed Alzheimer’s diagnosis to enroll?

Most disease-modifying trials require biomarker confirmation. Some prevention trials enroll people without a diagnosis but with risk factors, and some diagnostic studies enroll people still being evaluated.

Will I receive lecanemab or donanemab in a trial?

Usually not, since these are FDA-approved and prescribed clinically for early Alzheimer’s. Trials typically test newer agents, different anti-amyloid approaches, or combinations, and some involve a placebo group.

How does the study partner role work?

A study partner, often a spouse, adult child, or close friend, attends most visits, provides collateral history, and helps assess daily function. This role is required for many trials and is a real commitment of time.

Is joining a trial free, and could it help me?

Study-related procedures are typically provided at no cost, and some trials reimburse travel. But a trial is research, not guaranteed treatment; the goal is to answer a scientific question, and any personal benefit is uncertain.

Is the Alzheimer’s Association TrialMatch service free?

Yes. It is a free, registration-based service that matches you with appropriate trials based on your medical history, and it is a good complement to ClinicalTrials.gov and the Alzheimers.gov finder.

Sources

• ClinicalTrials.gov – clinicaltrials.gov
• National Institute on Aging (NIA/NIH), Participating in Alzheimer’s and dementia research – nia.nih.gov
• Alzheimers.gov, Clinical Trials Finder – alzheimers.gov
• Alzheimer’s Association, Lecanemab (Leqembi) – alz.org
• Alzheimer’s Association, Aducanumab (Aduhelm) discontinued – alz.org