Not every person with memory concerns is a candidate for Leqembi, and that’s actually good news — this medication is intended for a specific, carefully defined group of patients, and knowing the criteria upfront can save families a lot of confusion. In short, Leqembi is approved for people with early-stage Alzheimer’s disease, meaning mild cognitive impairment or mild dementia due to Alzheimer’s, who have confirmed amyloid plaque buildup in the brain. It is not intended for moderate or advanced Alzheimer’s, and it requires a series of diagnostic steps before treatment can even begin.
Below, we break down exactly who tends to qualify, what testing is involved, and what disqualifies someone from treatment — so you know what to expect if you or a loved one is exploring this option.
What Is Leqembi and Why Does Eligibility Matter So Much?
Leqembi (lecanemab) is an FDA-approved infusion therapy designed to slow the progression of Alzheimer’s disease by targeting amyloid beta plaques in the brain. Unlike older Alzheimer’s medications that only manage symptoms, Leqembi works on one of the underlying biological processes believed to drive the disease.
Because it works this way, it only makes sense — and only shows benefit — for a narrow window of the disease. Giving it too early (before confirmed amyloid pathology) or too late (once dementia is advanced) doesn’t produce meaningful results and may expose the patient to unnecessary risk. That’s why eligibility screening is such a rigorous, multi-step process.
The Core Eligibility Criteria for Leqembi
Generally speaking, candidates for Leqembi treatment must meet several conditions at once. A neurologist will evaluate all of the following before recommending the therapy:
- Diagnosis of early Alzheimer’s disease — mild cognitive impairment (MCI) or mild dementia stage, confirmed through cognitive testing and clinical evaluation.
- Confirmed amyloid plaques — verified through a PET scan or cerebrospinal fluid (CSF) analysis showing elevated amyloid beta levels.
- Appropriate age and overall health — most clinical candidates are older adults who are otherwise medically stable enough to tolerate regular infusions and monitoring.
- No significant bleeding risk factors — including certain blood thinner use, prior brain hemorrhage, or conditions that increase clotting or bleeding complications.
- ApoE4 genetic status is known — testing for this gene helps determine the patient’s individual risk of brain swelling or bleeding while on the medication, which shapes monitoring frequency.
- No contraindicated MRI findings — a baseline brain MRI is required to rule out existing abnormalities that would make treatment unsafe.
Who Is Generally NOT a Candidate
Just as important as who qualifies is understanding who doesn’t. Leqembi is typically not appropriate for:
- Patients with moderate to severe Alzheimer’s disease or other forms of dementia (such as vascular dementia or Lewy body dementia) without confirmed amyloid pathology.
- People with a history of significant brain bleeds, strokes, or certain clotting disorders.
- Patients currently on anticoagulant medications where the bleeding risk outweighs potential benefit.
- Anyone without confirmed amyloid buildup — cognitive symptoms alone are not enough for approval.
The Diagnostic Workup: What Happens Before Treatment Begins
Determining eligibility isn’t a single office visit — it’s a structured process. Most patients go through several stages of evaluation before a neurologist can confirm whether Leqembi is appropriate.
1. Cognitive and Neurological Assessment
The process starts with a detailed clinical history and cognitive testing to establish the stage of impairment. This helps rule out reversible causes of memory loss, such as thyroid dysfunction, vitamin deficiencies, or medication side effects, before moving forward.
2. Confirming Amyloid Status
This is the non-negotiable step. Amyloid buildup must be confirmed through either a PET scan or a lumbar puncture for CSF analysis. Without this confirmation, a patient cannot be started on Leqembi, regardless of how classic their symptoms may look.
3. Genetic and Safety Screening
ApoE4 genotyping is recommended to understand individual risk for amyloid-related imaging abnormalities (ARIA), a known side effect involving brain swelling or small bleeds. Patients who carry two copies of the ApoE4 gene face a higher risk and require closer monitoring throughout treatment.
4. Baseline and Ongoing MRI Monitoring
A baseline MRI is required before the first infusion, with follow-up scans at scheduled intervals during treatment. This monitoring is what allows a neurology team to catch ARIA early, often before it causes noticeable symptoms.
How Related Testing Fits Into the Bigger Picture
Because Alzheimer’s symptoms can overlap with other neurological conditions, the diagnostic process often draws on tools beyond amyloid imaging. For example, EEG testing can help rule out seizure activity that sometimes mimics or accompanies cognitive decline, while brain mapping may add useful detail about regional brain function.
Vascular contributions to cognitive symptoms are also worth ruling out. Tools like carotid Doppler studies and transcranial Doppler (TCD) assessments help a neurologist determine whether reduced blood flow or embolic activity is playing a role in a patient’s symptoms — which matters because vascular dementia is managed very differently than Alzheimer’s disease.
Leqembi vs. Traditional Alzheimer’s Medications
Families often ask how Leqembi compares to medications like donepezil or memantine, which have been used for years. The table below outlines the key differences.
| Feature | Leqembi | Traditional Alzheimer’s Medications |
|---|---|---|
| Mechanism | Targets and reduces amyloid plaques | Manages neurotransmitter levels to ease symptoms |
| Disease stage | Early Alzheimer’s (MCI or mild dementia) only | Can be used across mild to moderate/severe stages |
| Administration | IV infusion on a regular schedule | Oral tablets, typically daily |
| Pre-treatment testing required | Amyloid confirmation, genetic testing, MRI | Minimal specialized testing needed |
| Ongoing monitoring | Periodic MRIs to monitor for ARIA | Routine follow-up visits |
What the Infusion Process Involves
Once eligibility is confirmed, treatment is delivered as an intravenous infusion, typically administered on a biweekly schedule. Patients are monitored during and after infusions for any signs of an infusion reaction, and scheduled MRIs continue throughout the treatment course.
Because this is an ongoing commitment involving regular visits, many patients appreciate having their infusions, imaging, and cognitive follow-ups coordinated by the same neurology team rather than juggling multiple offices. You can read more about how the treatment itself works on our Leqembi treatment page.
Questions to Bring to Your Neurology Consultation
If you’re considering Leqembi for yourself or a family member, a productive first conversation with a neurologist often covers:
- Has amyloid pathology been confirmed, or does that testing still need to happen?
- What does my current cognitive testing suggest about disease stage?
- Are there bleeding or clotting risk factors in my medical history that need review?
- What does the MRI monitoring schedule look like once treatment starts?
- How will side effects like ARIA be detected and managed?
Bringing a list of current medications, recent imaging (if available), and a clear timeline of symptom changes will help the evaluation move efficiently.
Why Early Evaluation Matters
Because Leqembi is only approved for early-stage disease, timing is everything. Patients who wait too long to pursue evaluation may move past the window where this treatment can help. This is one of the strongest arguments for taking new memory or cognitive changes seriously and pursuing a full neurological workup rather than assuming it’s “just normal aging.”
For Long Island families navigating a new memory concern, having access to on-site diagnostic tools — from cognitive testing to vascular imaging to electrodiagnostic testing for related nerve symptoms — can streamline what might otherwise be a scattered, months-long referral process across multiple facilities.
Moving Forward With Confidence
Eligibility for Leqembi comes down to a specific combination of disease stage, confirmed amyloid pathology, and a safety profile that supports regular infusions and monitoring — not every memory concern will meet that bar, and that’s exactly why a thorough neurological evaluation matters before assuming this treatment is or isn’t the right fit. If you have questions about where you or a loved one stands, our team at Apex Neurology is glad to walk through the testing process and what it might mean for your specific situation. You can find more patient perspectives on our testimonials page, explore our full list of services, or find us directly on Google when you’re ready to schedule a conversation.
