EARLY REAL-WORLD ADHERENCE TO MRI SAFETY SURVEILLANCE AFTER LECANEMAB INITIATION AMONG MEDICARE BENEFICIARIES
Author(s)
emaan rashidi, MS1, Hemalkumar Mehta, MS, PhD2, Sonal Singh, MD, MPH3, Shuyan Dong, BA2, Ravi Gupta, MD4, Chen Dun, PhD, MS5, Calab Alexander, MD, MS6;
1Baltimore, MD, USA, 2Johns Hopkins Bloomberg School of Public Health, Baltimore, MD, USA, 3University of Massachusetts, Toronto, ON, Canada, 4Johns Hopkins University, Baltimore, MD, USA, 5Johns Hopkins School of Medicine, Baltimore, MD, USA, 6Johns Hopkins School of Public Health, Baltimore, MD, USA
1Baltimore, MD, USA, 2Johns Hopkins Bloomberg School of Public Health, Baltimore, MD, USA, 3University of Massachusetts, Toronto, ON, Canada, 4Johns Hopkins University, Baltimore, MD, USA, 5Johns Hopkins School of Medicine, Baltimore, MD, USA, 6Johns Hopkins School of Public Health, Baltimore, MD, USA
OBJECTIVES: U.S. Food and Drug Administration (FDA) approval of lecanemab for Alzheimer’s disease advises routine magnetic resonance imaging (MRI) to monitor for amyloid-related imaging abnormalities (ARIA), including microhemorrhage and cerebral edema; however, the extent to which such surveillance is implemented in routine clinical practice is unknown. We evaluated FDA-recommended MRI safety surveillance following lecanemab initiation among Medicare beneficiaries.
METHODS: We conducted a retrospective cohort study using a national 20% sample of Medicare fee-for-service claims from 2023. Using outpatient facility and physician procedure codes, we assessed completion of MRIs at infusions 1, 5, 7, and 14, as specified in the FDA label. Eligible beneficiaries initiated lecanemab, had continuous Part A/B coverage, and complete age, sex, and geographic information in the 12 months prior to initiation. We estimated the proportion receiving MRIs within recommended windows and characterized temporal patterns of surveillance over 6 months of follow-up.
RESULTS: Among 219 Medicare beneficiaries initiating lecanemab in 2023 (mean age 75.6 years, 53.0% male, and 91.8% White), 92.7% (n=203) received an MRI prior to the first infusion. Adherence declined substantially after treatment initiation: 60.0% (90/150) completed an MRI prior to the 5th infusion and 55.9% (59/105) prior to the 7th infusion. Very few beneficiaries underwent subsequent imaging, with 1 completing imaging before infusion 14. In contrast, infusion schedules remained consistent with labeling, with a median 14-day interval between infusions throughout follow-up.
CONCLUSIONS: In the first year of routine lecanemab use, adherence to FDA-recommended MRI safety surveillance declined after treatment initiation despite continued biweekly infusions. These findings suggest that many Medicare beneficiaries may be receiving ongoing therapy without recommended monitoring for ARIA, a common and well-characterized adverse event. This decline likely reflects structural barriers, including MRI access and care coordination. Improving alignment between regulatory requirements and real-world implementation may be necessary to support safe use of anti-amyloid therapies.
METHODS: We conducted a retrospective cohort study using a national 20% sample of Medicare fee-for-service claims from 2023. Using outpatient facility and physician procedure codes, we assessed completion of MRIs at infusions 1, 5, 7, and 14, as specified in the FDA label. Eligible beneficiaries initiated lecanemab, had continuous Part A/B coverage, and complete age, sex, and geographic information in the 12 months prior to initiation. We estimated the proportion receiving MRIs within recommended windows and characterized temporal patterns of surveillance over 6 months of follow-up.
RESULTS: Among 219 Medicare beneficiaries initiating lecanemab in 2023 (mean age 75.6 years, 53.0% male, and 91.8% White), 92.7% (n=203) received an MRI prior to the first infusion. Adherence declined substantially after treatment initiation: 60.0% (90/150) completed an MRI prior to the 5th infusion and 55.9% (59/105) prior to the 7th infusion. Very few beneficiaries underwent subsequent imaging, with 1 completing imaging before infusion 14. In contrast, infusion schedules remained consistent with labeling, with a median 14-day interval between infusions throughout follow-up.
CONCLUSIONS: In the first year of routine lecanemab use, adherence to FDA-recommended MRI safety surveillance declined after treatment initiation despite continued biweekly infusions. These findings suggest that many Medicare beneficiaries may be receiving ongoing therapy without recommended monitoring for ARIA, a common and well-characterized adverse event. This decline likely reflects structural barriers, including MRI access and care coordination. Improving alignment between regulatory requirements and real-world implementation may be necessary to support safe use of anti-amyloid therapies.
Conference/Value in Health Info
2026-05, ISPOR 2026, Philadelphia, PA, USA
Value in Health, Volume 29, Issue S6
Code
EPH133
Topic
Epidemiology & Public Health
Topic Subcategory
Safety & Pharmacoepidemiology
Disease
SDC: Geriatrics, SDC: Neurological Disorders