Alzheimer’s Drug LEQEMBI Shows Strong Real-World Persistence Beyond 18 Months

In Alzheimer’s treatment, efficacy is only half the story. The other half? Do patients actually stay on therapy long enough to benefit? New real-world data suggests the answer for LEQEMBI is yes.

The Update: High Long-Term Adherence in Real-World Use

Eisai Co., Ltd. and Biogen Inc. reported new findings for lecanemab (LEQEMBI) at the AD/PD 2026 Conference.

Key takeaway:

Most patients continue treatment well beyond the initial 18 months

The Data: What Persistence Looks Like

The analysis used U.S. real-world data from over 10,000 patients.

Among patients with long-term follow-up:

• 78.4% remained on treatment at 18 months
• 71.7% at 20 months
• 67.3% at 24 months

That’s unusually high persistence for a chronic neurological therapy.

Why This Matters?

In chronic diseases like Alzheimer’s:

• Longer treatment → better outcomes
• Higher adherence → higher patient benefit

This data suggests LEQEMBI is not just clinically effective, it’s practically usable in real-world settings.

Backed by Clinical Trial Continuation

The real-world data aligns with earlier trial behavior. In the Phase III Clarity AD study:

• 94% of patients who completed 18 months
• Chose to continue into the long-term extension

Strong signal of patient and physician confidence

What LEQEMBI Actually Does?

LEQEMBI is a monoclonal antibody targeting amyloid-beta (Aβ), a key driver of Alzheimer’s disease.

Mechanism:

• Binds to toxic amyloid protofibrils
• Reduces plaque formation
• Slows cognitive decline

Long-Term Impact: Slowing Disease Progression

Over multiple years of treatment:

• Reduced cognitive decline vs expected progression
• Benefits increased over time (3–4 years data)

Why this matters:

Alzheimer’s is progressive. Slowing decline—even modestly, can extend independence and quality of life

Real-World Use: Practical Insights

Patient profile:

• Average age: ~74 years
• 56.5% female
• Common comorbidities:
  • Hypertension
  • Dyslipidemia

Dosing pattern:

• ~Every 2 weeks (aligned with guidelines)
• Average: 1.7 doses per month

Real-world usage closely mirrors clinical trials

Barriers Didn’t Break Adherence

Despite known challenges:

• MRI monitoring requirements
• Infusion-based administration
• Potential side effects

Adherence remained high This is a critical signal for long-term commercial success.

Expanding Access: What’s Next?

LEQEMBI is already approved in:

• U.S.
• Japan
• China
• Europe
• 50+ countries overall

Pipeline expansion:

• Subcutaneous (at-home) formulation
• Monthly maintenance dosing
• Ongoing studies in early/preclinical Alzheimer’s

The goal: simplify treatment and expand access

Strategic Positioning: A Long-Term Alzheimer’s Play

The collaboration between Eisai and Biogen is structured for scale:

• Eisai leads development and regulatory strategy
• Both companies co-commercialize globally

This ensures:

• Faster global rollout
• Strong commercialization infrastructure

The Bigger Picture: Alzheimer’s Treatment Is Evolving

We’re seeing a shift:

Old model:

• Symptom management

New model:

• Disease-modifying therapies

LEQEMBI is part of the first wave attempting to: Slow disease progression, not just manage symptoms

The Bottom Line

These findings answer a critical question: Will patients stay on Alzheimer’s therapy long enough to benefit?

For LEQEMBI, the answer appears to be yes.

• High real-world adherence
• Sustained long-term use
• Growing clinical benefit over time

If this trend continues, LEQEMBI could become: A foundational therapy in early Alzheimer’s management