Share on Pinterest- A real-world study found that most patients receiving the anti-amyloid therapy Leqembi (lecanemab) remained clinically stable after 17 months, with 75.9% remaining at the same stage and 6.6% improving by 1 disease stage, for an overall 82.5% stable or improved.
- Clinical stability was reported regardless of sex, race, ethnicity, or APOE e4 genetic status, suggesting consistent real-world effectiveness across a diverse patient population.
- Nearly 87% of participants continued Leqembi treatment, indicating that most patients remained on therapy in routine clinical practice.
- Safety was consistent with previous studies, with adverse events occurring in 12.3% of people, with most cases reported as mild and asymptomatic, aligning with the drug’s established safety profile from clinical trials.
At present, there is no cure for Alzheimer’s disease. Current treatment approaches include lifestyle changes, therapies, and medications, which may slow the progression of the condition and manage its symptoms
Some medications, known as anti-amyloid therapy, aim to reduce the buildup of beta-amyloid plaques
in the brain, a hallmark of the disease. However, recent research has questioned the effectiveness of these medications
While receiving treatment for Alzheimer’s, maintaining clinical stability is an important goal. It can allow an individual to preserve cognitive function, independence, and quality of life for as long as possible
Now, a real-world study, presented at the Alzheimer’s Association International Conference (AAIC) 2026, noted that more than three-quarters of people with early Alzheimer’s disease who received the anti-amyloid therapy Leqembi (lecanemab) remained at the same stage of disease after an average of 17 months of treatment
The data were presented at AAIC 2026 but has not yet undergone peer review or been published in a scientific journal
What is the LEADER study?
The drug manufacturers Eisai and Biogen released press statements highlighting findings from the LEADER (Lecanemab in Early Alzheimer’s Disease) study, an ongoing retrospective analysis evaluating how lecanemab performs in routine clinical practice across multiple healthcare centers in the United States
As an antibody intravenous (IV) infusion therapy, Leqembi has Food and Drug Administration (FDA) approval for treating early Alzheimer’s disease. This included those living with mild cognitive impairment (MCI) or mild dementia due to Alzheimer’s disease with elevated beta-amyloid in the brain
In July 2026, the FDA
also approved a supplemental Biologics License Application (sBLA) for a once‑weekly LEQEMBI IQLIK subcutaneous injection as an at-home starting dose for early Alzheimer’s disease
Unlike randomized clinical trials, which test treatments under carefully controlled conditions, the LEADER study was a real-world study examining outcomes in patients receiving treatment as part of standard medical care
LEADER study findings
The interim analysis included 432 participants who had received at least 7 Leqembi infusions and had sufficient follow-up data to assess changes in disease stage
Researchers reported that treatment outcomes appeared broadly consistent across sex, race, ethnicity, and APOE e4 genetic status, a gene variant associated with an increased risk of Alzheimer’s disease
According to the study investigators, 75.9% of patients remained clinically stable over the treatment period, while an additional 6.6% improved by one disease stage
This means that nearly 83% of evaluable participants were either stable or showed improvement after receiving Leqembi for an average of 17 months
Dung Trinh, MD, an internist at MemorialCare Medical Group and Chief Medical Officer of Healthy Brain Clinic in Irvine, CA, who was not involved in the study, told Medical News Today:
“The most important takeaway is that lecanemab appears feasible to deliver and monitor in routine clinical practice, with 75.9% of evaluable patients remaining in the same broad disease stage and another 6.6% moving from mild dementia to the MCI category after an average of approximately 17 months.”
“These findings are encouraging, but stability in this study meant remaining within the same broad clinical stage, not necessarily experiencing no cognitive or functional decline,” Trinh explained
The investigators also found that nearly 87% elected to continue treatment, suggesting a high level of treatment persistence in routine clinical practice
“Remaining in an earlier stage of Alzheimer’s disease for longer can be meaningful to patients and families because it may preserve independence, communication, participation in family life, and the ability to make decisions and plans,” Trinh told us
“However, the term clinically stable should be interpreted carefully because patients may still decline within the MCI or mild-dementia stage without progressing to the next category. The finding is therefore an encouraging real-world signal rather than a guarantee of individual benefit, and the patients who moved from mild dementia to MCI should not be described as having experienced a cure or reversal of Alzheimer’s disease,” he added
Safety findings consistent with previous studies
The safety profile reported in the study was generally consistent with earlier clinical trials and the FDA-approved label
Amyloid-related imaging abnormalities (ARIA) describe a known side effect of anti-amyloid therapies that can involve brain swelling or small areas of bleeding. This adverse event occurred in 12.3% of participants, but the investigators state that most cases were asymptomatic and mild
The researchers also reported encouraging findings among those who transitioned to once-monthly intravenous (IV) maintenance dosing
Of the 432 participants, 155 transitioned to once-every-4-weeks IV maintenance therapy, where 72.3% remained stable and 8.4% improved
How do these findings compare with earlier research?
The CLARITY AD clinical trial previously demonstrated that lecanemab could slow cognitive decline in people with early Alzheimer’s disease over 18 months compared with a placebo to help establish the drug’s possible clinical benefit
The new LEADER data provide evidence that the treatment may be similarly effective in everyday clinical settings, where individuals are generally more diverse and may have additional health conditions that are often excluded from clinical trials
“CLARITY AD and LEADER provide different but complementary forms of evidence,” Trinh noted
“CLARITY AD offers randomized, placebo-controlled evidence that lecanemab slows cognitive and functional decline on average, while LEADER provides information about how treatment is being delivered in everyday practice, including treatment persistence, safety monitoring, clinical-stage patterns, and the transition to maintenance therapy.”— Dung Trinh, MD
“Randomized trials are the stronger help clinicians understand implementation and patient experience outside the controlled trial environment. LEADER therefore complements the CLARITY AD evidence but does not replace it,” Trinh said
Real-world evidence can also help clinicians better understand how therapies perform in routine practice, including patient adherence, safety monitoring, and longer-term outcomes
Experts urge cautious interpretation
Although the findings are encouraging, several study limitations should be considered
The LEADER study is observational and retrospective rather than a randomized controlled trial. As such, there is no untreated comparison group. Therefore, it is not possible to determine how much of the observed disease stability is attributable directly to the medication
“Clinicians should view the LEADER findings as supportive and hypothesis-generating rather than proof of a treatment effect. Without an untreated comparison group, it is impossible to determine how many similar patients would have remained in the same disease stage without lecanemab.”— Dung Trinh, MD
“The retrospective design, broad disease-stage categories, potential inconsistencies in medical records, and requirement that patients receive at least seven infusions may also introduce selection bias by excluding some patients who discontinued treatment earlier because of adverse events, medical issues, logistical barriers, or personal preference,” Trinh told MNT
“The results are most useful as evidence about real-world feasibility, persistence, monitoring, and safety,” he noted
Additionally, disease progression was assessed using clinicians’ evaluations of disease stage rather than standardized cognitive outcome measures alone. The results also represent an interim analysis, meaning additional follow-up may provide a more complete picture of long-term effectiveness and safety
What this means for future Alzheimer’s treatment
The researchers plan to continue following participants in the LEADER study to evaluate longer-term outcomes, including treatment persistence, maintenance dosing strategies, and the effectiveness of newer administration approaches, such as subcutaneous formulations currently under investigation
As disease-modifying therapies for Alzheimer’s disease become more widely available, real-world studies like LEADER may help clinicians understand who benefits most from treatment and how these therapies perform in settings outside clinical trials
However, randomized controlled trials remain the strongest form of evidence for determining treatment efficacy, with observational studies viewed as complementary
“The results do not fundamentally change treatment eligibility or established safety requirements, but they may give clinicians greater confidence that lecanemab can be integrated into routine care when the necessary diagnostic, imaging, monitoring, and care-coordination systems are in place.”— Dung Trinh, MD
“Decisions should remain individualized and should consider confirmation of amyloid pathology, the expectation that treatment slows rather than stops decline, ARIA and hemorrhage risks, APOE ε4 status, MRI monitoring, anticoagulant or antithrombotic use, treatment burden, patient goals, and caregiver support,” Trinh said
“The findings also reinforce the importance of a coordinated pathway that begins with primary care recognition and evaluation, uses blood-based biomarkers appropriately for triage, includes specialist confirmation and treatment-readiness assessment, and continues with shared follow-up between specialists and primary care,” he concluded
