Dementia & Memory Care

Anti-Amyloid Infusions for Alzheimer's, Explained

Anti-amyloid infusions target Alzheimer's biology itself. How they work, what benefit looks like on average, the ARIA risk, and who they may not suit.

Prepared with AI assistance and checked against the linked sources. The update date records an editorial revision; it does not certify physician review.

Zaka Ahmed, MD

Vascular Neurologist · 28 October 2026 · 9 min read

Key Takeaways

Anti-amyloid infusions are the first treatments that target Alzheimer's biology itself — and they help modestly, on average, rather than curing or reversing dementia.

→ What they do: These medicines are antibodies, given by vein, that help clear amyloid plaques — clumps of protein that build up in the Alzheimer's brain.
→ What benefit looks like: In large trials, people on treatment declined more slowly on memory and function rating scales than people on placebo — a modest average slowing, not a recovery of lost memory.
→ The main risk: ARIA — swelling or small bleeds visible on MRI — usually without symptoms, watched for with scheduled safety scans.
→ Who they suit: People at the mild stage (mild cognitive impairment or mild dementia) with Alzheimer's biology confirmed. Many people do not qualify, and that is not a failure.

When Robert, 68, first heard about an Alzheimer's infusion, he heard two versions of the story at once.

One version, from headlines, sounded like a breakthrough that could give him his memory back. The other, from his daughter, sounded like a warning about brain swelling. At his clinic visit, the truth turned out to be quieter than either version: a treatment that may slow decline a little, for some people, with real risks, real effort, and no promise attached to any one person. He left with a clearer picture — and a decision he could live with either way.

This page gives you that same picture: how these infusions work, what benefit realistically looks like, what the risks are, and who they may not suit.

What this means

Alzheimer's disease involves the build-up of amyloid plaques — clumps of a protein called amyloid-beta — between brain cells, along with tangles of a protein called tau inside them. Standard Alzheimer's medicines (such as donepezil and memantine) can ease symptoms for a time, but they do not remove plaques or change the underlying biology.

Anti-amyloid infusions are different in kind. They are laboratory-made antibodies — proteins designed to recognize amyloid — given into a vein. Once in the bloodstream, they reach the brain and help the body's own systems clear amyloid plaques. Brain scans in trials showed substantial plaque removal in many people on treatment.

That biology matters, but it is not the same as benefit. Removing plaques is a laboratory result; what patients and families care about is memory, thinking, and daily life. Trials measured those with rating scales, and that is where the honest conversation starts.

What benefit looks like, honestly

In the large trials of these medicines, people receiving treatment declined more slowly, on average, than people receiving a placebo infusion, over about 18 months. The difference was modest — roughly a quarter to a third slower on the trial rating scales. To put that plainly: the treatment group still declined. The slope was gentler, not flat, and certainly not reversed.

What that may mean for one person is impossible to promise in advance. Some people may notice little difference; others may feel they held steadier for longer. No trial result can tell you which group you may fall into, and no honest clinician can promise an individual outcome. What can be said is that these are the first treatments shown to slow decline on average by targeting Alzheimer's biology — a real step, and a modest one.

It also helps to say what these treatments do not do: they do not restore memory that is already lost, they do not cure dementia, and they do not help every type of dementia — they are for Alzheimer's disease specifically, at the mild stage, with amyloid confirmed.

What an infusion visit is like

Kisunla is given as an infusion at an infusion center. Leqembi can be given the same way, or as a weekly injection under the skin (Leqembi Iqlik) that can be done at home. Your care team decides which option fits. A typical infusion visit looks like this:

Check-in and vitals. Blood pressure, temperature, and a brief check of how you have been since the last visit.
The drip. An IV line is placed, usually in the arm, and the medicine runs in over roughly an hour (the exact time depends on the therapy).
Monitoring. Staff watch for reactions during and after the drip. The whole visit often takes 2–4 hours.
Home the same day. Most people go home afterwards, often with a companion for the first few visits.

Leqembi is given every two weeks by infusion, or weekly by injection at home; later on, the schedule can move to every four weeks by infusion or a lower weekly injection. Kisunla is given every four weeks, and its label says doctors can consider stopping once a scan shows the amyloid has cleared. That rhythm is part of the decision: it means regular travel, regular appointments, and regular MRI scans (see below).

Risks: ARIA and infusion reactions

ARIA stands for amyloid-related imaging abnormalities. It is the main risk of anti-amyloid treatment, and it comes in two forms: ARIA-E (swelling in the brain, seen on MRI) and ARIA-H (small bleeds or iron deposits, also seen on MRI). ARIA is usually found on scheduled safety MRI scans before it causes any symptoms, and it often resolves on its own or after pausing treatment. When symptoms do occur, they may include headache, confusion, dizziness, vision change, or nausea.

Serious ARIA is uncommon, but it can happen, and a small number of serious events have been reported. Risk is higher in people who carry two copies of the APOE ε4 gene variant — one reason APOE discussion is part of the eligibility conversation. Blood thinners and a history of brain bleeds also affect risk, and the clinic reviews both before starting.

Infusion reactions — fever, chills, flushing, or rash during or after the drip — can also occur. Staff monitor for these on site and treat them promptly.

Because of ARIA, treatment includes a schedule of safety MRI scans: a baseline scan before starting, and further scans at set intervals during treatment. Missing those scans is not an option — they are how the treatment is made as safe as it can be.

Who infusions may not suit

Many people with Alzheimer's do not qualify for infusions, and many who qualify choose not to take them. Reasons may include:

Dementia beyond the mild stage, where trials did not show benefit.
Alzheimer's biology not confirmed by biomarker testing.
MRI findings that raise the risk (for example, many microbleeds or prior hemorrhage).
Blood thinners or other conditions that make treatment unsafe.
The burden itself: regular travel, infusions, and scans, weighed against a modest average benefit.

Not qualifying — or choosing not to proceed — is not the end of care. Standard medicines, planning, safety steps, activity, and support still help, and the clinic's job is to build that plan with the same care. The eligibility pathway page walks through each step of the selection process.

Cost, travel, and practical questions

How much does it cost? Infusions, scans, and monitoring are expensive, and coverage varies by health plan and by region. This page deliberately does not quote a price, because prices and coverage rules change. Before starting, the clinic verifies coverage with your plan and reviews what you may owe, so there are no surprises.

How often, and for how long? Leqembi: every two weeks by infusion or weekly by injection at home, with less frequent options later. Kisunla: every four weeks, and stopping can be considered once amyloid has cleared on a scan. Stopping rules — for example, if ARIA appears or if dementia advances beyond the mild stage — are discussed before starting and reviewed at follow-ups.

Do I need someone with me? A companion for the first visits is recommended, and helpful for every visit: travel, waiting, and remembering instructions are all easier shared.

For clinicians

Mechanism and evidence. Anti-amyloid monoclonal antibodies (lecanemab, donanemab) clear cerebral amyloid as measured by PET and CSF/plasma biomarkers. In phase 3 trials, treatment slowed decline on the CDR-SB primary endpoint by roughly a quarter to a third relative to placebo over 18 months (Clarity AD: lecanemab; TRAILBLAZER-ALZ 2: donanemab), with absolute differences of under one point on the 18-point CDR-SB scale — a modest effect size that frames consent discussions. Benefit has been demonstrated in MCI due to Alzheimer's and mild Alzheimer's dementia with confirmed amyloid pathology; evidence beyond the mild stage is lacking.

ARIA. ARIA-E incidence was roughly 10–25% and ARIA-H roughly 15–30% across the phase 3 programs (varying by agent, dose, and APOE status); most cases were asymptomatic and detected on scheduled surveillance MRI. APOE ε4 homozygotes carry substantially higher ARIA risk and warrant explicit counseling. Symptomatic ARIA, macrohemorrhage, and rare serious outcomes have been reported; management is dose interruption or discontinuation per labeling, with urgent evaluation for new headache, confusion, visual change, or focal symptoms.

Monitoring. Baseline MRI required, with surveillance MRIs at protocol intervals (per current labeling for the agent used); anticoagulation review and microbleed/siderosis assessment are part of baseline safety evaluation. Plasma biomarkers may support triage, but definitive amyloid confirmation (CSF or amyloid PET) remains the standard before treatment initiation in most protocols.

References. van Dyck CH, et al. Lecanemab in early Alzheimer's disease (Clarity AD). New England Journal of Medicine, 2023 · Sims JR, et al. Donanemab in early symptomatic Alzheimer disease (TRAILBLAZER-ALZ 2). JAMA, 2023 · Jack CR Jr, et al. Revised criteria for diagnosis and staging of Alzheimer's disease (NIA-AA). Alzheimer's & Dementia, 2024.

Frequently asked questions

Do infusions cure Alzheimer's?

No. They may slow decline modestly on average. They do not restore lost memory and they do not cure dementia.

What is ARIA?

Swelling (ARIA-E) or small bleeds (ARIA-H) visible on MRI — the main risk of anti-amyloid treatment. It is usually found on scheduled safety scans before causing symptoms, and it often resolves after pausing treatment.

How often are infusions given?

Leqembi every two weeks by infusion, or weekly by injection at home. Kisunla every four weeks by infusion. Both need MRI monitoring at set times.

Does insurance cover infusions?

Coverage varies by plan and region, and rules change. The clinic verifies coverage with your plan before starting and reviews any costs with you.

What if I don't qualify?

Standard medicines, planning, safety steps, activity, and caregiver support still help. The clinic builds that plan with the same care — not qualifying is not the end of care.

Can I stop treatment later?

Yes. Stopping rules — including ARIA, advancing stage, or personal choice — are discussed before starting and reviewed at follow-ups. Stopping is always an option.

Takeaways

Anti-amyloid infusions clear amyloid plaques and, in trials, slowed decline modestly on average — a real but limited benefit, not a cure or a restoration of memory.
The main risk is ARIA, watched for with scheduled MRI scans; infusion reactions can also occur and are managed on site.
These treatments suit a defined group — mild-stage Alzheimer's with confirmed amyloid — and the decision deserves an unhurried conversation about benefit, risk, and burden.

This article is for education only and is not medical advice. It does not diagnose any individual person or recommend treatment for any individual. If sudden confusion, severe headache, vision change, or any rapid change occurs, seek urgent care; call 911 for emergencies.

When to call us: book a memory assessment if memory change is noticed by you or family, if it affects daily life, or if it is getting worse. During infusion treatment, call promptly for new headache, confusion, dizziness, vision change, nausea, or anything unusual after a visit.