The arrival of new Alzheimer's treatments has brought both hope and uncertainty. For the first time, medications are available that can slow the biological process of Alzheimer's disease, rather than only treating symptoms. At the same time, these treatments are not appropriate for everyone, and careful screening is essential.
It is important to understand what these treatments do and do not do.
What Are Disease-Modifying Therapies?
Disease-modifying therapies are medications designed to slow the underlying disease process of Alzheimer's disease. Current approved therapies work by reducing amyloid, a protein that builds up in the brain years before symptoms appear.
They may:
- Slow thinking and memory decline
- Help some people remain in a milder stage longer
- Alter measurable brain biology
They do not:
- Cure Alzheimer's disease
- Restore lost memory
- Stop progression entirely
Benefits are typically modest, measured over months to years, and vary from person to person. For this reason, deciding whether to pursue treatment requires thoughtful discussion.
Why Timing Matters More Than Anything Else
The single most important factor is stage of disease.
These treatments were studied only in people with:
- Mild Cognitive Impairment (MCI) due to Alzheimer's disease, or
- Mild Alzheimer's dementia
At these early stages:
- Daily independence is largely preserved
- Brain damage is present but not widespread
- Slowing the disease may meaningfully affect future function
People with moderate or advanced dementia were not included in trials because, by that stage, removing amyloid alone is unlikely to help. The brain has already sustained too much structural injury.
In short:
These therapies work best when started early—but not before symptoms exist.
Confirming Alzheimer's Biology
Not all memory problems are caused by Alzheimer's disease. Even when symptoms look similar, the underlying cause may be different.
Before starting treatment, it is essential to confirm that amyloid is actually present in the brain. This is done through:
- Amyloid PET imaging, or
- Spinal fluid testing
Amyloid confirmation ensures that treatment is targeting the correct disease. However, amyloid alone does not tell the whole story.
Why Tau Matters So Much
Another protein, called tau, reflects how much damage has already occurred inside brain cells.
- Lower tau levels suggest earlier disease and a greater chance of benefit
- Higher tau levels suggest more advanced disease, where benefit is less likely
In long-term studies, some people with low tau burden remained stable—or even slightly improved—over several years. In contrast, people with advanced tau pathology showed much less response.
Why this matters:
Amyloid removal helps most when the disease has not yet fully spread through brain networks.
MRI Screening: Protecting Safety
MRI scans are required before and during treatment. They are not optional.
MRI helps identify conditions that increase the risk of treatment-related complications, such as brain swelling or bleeding. Treatment is generally avoided if MRI shows:
- Multiple prior small brain bleeds
- Evidence of fragile amyloid-affected blood vessels
- Extensive white matter damage
- Signs of inflammation in amyloid-laden vessels
These findings suggest the brain's blood vessels may be too vulnerable to tolerate therapy safely.
Understanding Side Effects and Monitoring
The most important treatment-related risk is a group of changes seen on MRI called ARIA, which may involve:
- Brain swelling
- Small areas of bleeding
Many cases cause no symptoms and resolve with monitoring, but some can be serious. This is why:
- MRI scans are scheduled regularly
- Symptoms are monitored closely
- Treatment may be paused or stopped if changes occur
When patients are carefully screened and monitored, serious complications are uncommon.
Genetics and Individual Risk
Some people carry a genetic variant called APOE-e4.
This gene:
- Increases Alzheimer's risk overall
- Increases the likelihood of MRI changes during treatment
- Does not mean treatment cannot help
Knowing APOE status helps guide monitoring intensity and shared decision-making. Many people with this gene still choose treatment after discussing risks and benefits.
When Treatment Is Not Recommended
Disease-modifying therapy is usually not appropriate for people with:
- Moderate or severe dementia
- Recent stroke or uncontrolled seizures
- Use of blood-thinning medications
- Significant vascular brain disease
- Active autoimmune or inflammatory conditions requiring immune-suppressing medications
- Inability to safely complete MRI monitoring
- Lack of reliable support for ongoing care and follow-up
Choosing not to pursue treatment is often a medically sound and compassionate decision.
The "Right Fit" Patient
People most likely to benefit tend to share a common profile:
- Early symptoms affecting memory or thinking
- Clear evidence of Alzheimer's disease biology
- Limited tau-related brain damage
- MRI findings that support safe treatment
- Stable overall medical health
- A clear understanding of risks, benefits, and expectations
- A care partner who can help monitor changes
This is sometimes described as the therapeutic sweet spot.
What If Someone Is Not Eligible?
Not being eligible does not mean there is nothing to do.
Care continues to focus on:
- Optimizing sleep, mood, and medical health
- Supporting daily function and independence
- Treating symptoms when appropriate
- Planning for the future
- Supporting caregivers
Many people live meaningful, stable lives for years without disease-modifying therapy.
The Bottom Line
Disease-modifying therapies represent an important step forward—but they are not a universal solution.
The goal is not to treat everyone.
The goal is to treat the right people, at the right time, in the safest way possible.
Deciding whether to start treatment is a shared process that considers biology, safety, values, and quality of life. Both choosing treatment and choosing not to treat can be appropriate, thoughtful decisions.
Your care team will revisit this conversation over time as circumstances evolve.