Objective:

Evaluate lecanemab treatment patterns and MRI use among commercial and Medicare Advantage patients.

Background:

In 2023, accelerated approval was granted to lecanemab (Leqembi®) for treatment of mild cognitive impairment or dementia due to Alzheimer’s disease. Amyloid-related imaging abnormalities were reported in trials, resulting in discontinuation and need for brain magnetic resonance imaging (MRI) prior to infusions 5, 7, and 14. However, data are limited on real-world lecanemab treatment patterns and MRI use.

Design/Methods:

This study using administrative claims from the Healthcare Integrated Research Database included patients with ≥1 lecanemab infusion between 1/1/2023–12/31/2024. Date of first infusion was defined as index. 12 months prior to but not including index was defined as baseline. Time from index to earliest of disenrollment, 12/31/2024, or death was defined as follow-up. Discontinuation was defined as >42-day gap after any infusion before receipt of next.

Results:

865 patients with lecanemab infusion were included (mean±standard deviation index age: 73±8 years; 53% females). Over a follow-up of 7±4 months, 33% of patients discontinued after 6±5 infusions of which 40% restarted lecanemab. 20% of patients discontinued without restart. Baseline MRI was observed for 87% of patients and patients had 2.1±1.4 monitoring MRIs. Of patients with a monitoring MRI, 29% did so before infusion 4 and 21% of all patients received more than the one MRI expected per label before infusion 6. Of patients with two monitoring MRIs, 31% did so before infusion 6 and 24% of all patients received more than the two MRIs expected before infusion 13. Among restarters, 73% had an MRI between the infusion prior to discontinuation and reinitiation.

Conclusions:

Evidence suggests discontinuation of lecanemab is common and MRI use is more frequent and earlier than expected per label. Investigation of the relationship of effectiveness and adverse events with these discontinuation patterns is needed.