Lecanemab AD Treatment Could Have Low Eligibility Rate

Lecanemab, a recently FDA-approved treatment for Alzheimer disease (AD) may have a low eligibility rate (6.2%) among patients aged 70-89 years, according to recent results published in the journal Neurology. 

Researchers examined a population-based cohort from the Gothenburg H70 Birth Cohort Study (H70-BCS) of participants born in 1944. The following populations included in the study were eligible for lecanemab treatment for AD, according to FDA-approved recommendations: those with mild cognitive impairment (MCI) or mild dementia (clinical dementia rating of 0.5–1) and amyloid positivity (CSF-Aβ42 < 530 pg/mL). During the study, participants were comprehensively evaluated with tools including psychiatric assessments, cognitive testing, blood sampling, brain MRI, and lumbar puncture. Special consideration factors, such as past stroke and use of any anticoagulant medication, which could exclude individuals from treatment, were also identified. The study included all eligible citizens born on specific dates in 1944, without any exclusion criteria. The authors then used the results to estimate the number of eligible individuals in Europe and the United States.

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In the Gothenburg H70 Birth Cohort Study, 1944, 1203 participants were assessed, with 290 having complete data. Among these, 30 (10.3%) met the indication for treatment, but 12 required special considerations before treatment. Thus, 18 participants (6.2%) were eligible without risk factors. The sample was representative of the broader cohort, though men and those with special consideration factors were slightly overrepresented. Extrapolating these findings, approximately 5.9 million individuals in the EU between and 2.2 million in the US between 70 and 89 years (6.2% for each) might be eligible for lecanemab treatment.

Researchers noted that their analysis may underestimate eligibility due to focusing exclusively on 70-year-olds, but this could be mitigated due to a lower proportion of individuals with stroke and anticoagulant treatment in the sample. The small, ethnically homogeneous sample (290 of 1,203) and varying AD risk factors across countries could also have affected the generalizability of the findings.

“Other large population-based studies should determine the proportion in other settings to provide further information regarding the magnitude of individuals who may benefit from lecanemab treatment,” authors concluded. 

Reference
Dittrich A, Westman E, Shams S, et al. Proportion of community-dwelling individuals older than 70 years eligible for lecanemab initiation. Neurology. 2024;102(9). doi.org/10.1212/WNL.0000000000209402.