How do you manage associated autoimmune disease in patients with dementia using subcutaneous (sc) lecanemab infusion?

Management of Autoimmune Disease in Patients Using Subcutaneous Lecanemab for Dementia

Patients with pre-existing autoimmune conditions who are receiving lecanemab for early Alzheimer's disease require careful monitoring and multidisciplinary management, as they may be at higher risk for both autoimmune flares and treatment-related adverse events.

Pre-Treatment Assessment

• Perform comprehensive evaluation of autoimmune disease status, including disease activity markers and organ involvement, before initiating lecanemab 1
• Assess baseline immunosuppressive regimen and determine if adjustments are needed prior to lecanemab initiation 1
• Consider APOE genotyping to better inform risk discussions, as APOE4 carriers (especially homozygotes) have higher risk of amyloid-related imaging abnormalities (ARIA) 2, 3
• Evaluate for contraindications, particularly anticoagulant use, which significantly increases risk of intracerebral hemorrhage with lecanemab 2, 4

Monitoring During Treatment

• Monitor for both autoimmune disease flares and lecanemab-related adverse events with regular clinical assessments 1
• Schedule more frequent laboratory monitoring of autoimmune markers and inflammatory parameters than standard protocols 5
• Perform regular MRI evaluations to monitor for ARIA, which may be more common in patients with autoimmune conditions 2, 3
• Monitor closely for infusion-related reactions, which occur in approximately 24.5% of patients receiving lecanemab 4

Management of Autoimmune Disease Flares

• For mild autoimmune flares without significant organ involvement, consider continuing lecanemab while adjusting immunosuppressive therapy 1
• For moderate flares, temporarily hold lecanemab and increase immunosuppressive therapy as needed for the specific autoimmune condition 1
• For severe flares with major organ involvement, permanently discontinue lecanemab and initiate high-dose corticosteroids (1-2 mg/kg/day prednisone equivalent) 1
• Consider additional immunosuppressive agents based on the specific autoimmune condition and severity of flare 1

Management of Specific Autoimmune Complications

Rheumatologic Disorders

• For rheumatoid arthritis or psoriatic arthritis flares, adjust disease-modifying antirheumatic drugs (DMARDs) while continuing lecanemab if flare is mild to moderate 1
• For severe flares or vasculitis, temporarily hold lecanemab and consider pulse corticosteroids 1

Neurologic Autoimmune Disorders

• For patients with pre-existing autoimmune neurologic conditions (multiple sclerosis, myasthenia gravis), consider neurology consultation before initiating lecanemab 1
• If neurologic symptoms worsen, immediately hold lecanemab and obtain MRI to distinguish between ARIA and autoimmune flare 1
• For severe neurologic symptoms, permanently discontinue lecanemab and consider IVIG or plasmapheresis in addition to corticosteroids 1

Hematologic Abnormalities

• Monitor complete blood count regularly to detect neutrophilia or lymphopenia 5
• For grade 1-2 lymphopenia (500-1,000 lymphocytes/μL), continue close monitoring with regular CBC checks 5
• For grade 3-4 lymphopenia (<500 lymphocytes/μL), consider Pneumocystis jirovecii prophylaxis and CMV screening 5

Management of Lecanemab-Related Adverse Events

ARIA Management

• For asymptomatic ARIA-E (edema), continue lecanemab with close monitoring 2, 3
• For symptomatic ARIA-E, temporarily hold lecanemab until resolution and consider short-term corticosteroids if symptoms are significant 2
• For ARIA-H (microhemorrhages), management depends on number and symptoms - fewer than 10 asymptomatic microhemorrhages may not require interruption 2, 4
• For macrohemorrhage, permanently discontinue lecanemab 2, 4

Infusion Reactions

• Pre-medicate patients with antihistamines, antipyretics, and/or corticosteroids if previous infusion reactions occurred 2
• For mild-moderate reactions, slow or temporarily interrupt the infusion 2
• For severe reactions, discontinue lecanemab permanently 2

Special Considerations

• Patients requiring anticoagulation should not receive lecanemab due to increased risk of intracerebral hemorrhage 2, 4
• Patients with multiple autoimmune conditions may require more complex management and more frequent monitoring 1
• Consider non-pharmacological interventions to reduce fall risk, as falls could be particularly dangerous in patients on lecanemab 6

Communication and Shared Decision Making

• Discuss with patients and caregivers the potential benefits of lecanemab against the increased risks in the setting of autoimmune disease 2, 3
• Establish clear protocols for reporting new or worsening symptoms of either autoimmune disease or lecanemab-related adverse events 2
• Develop a multidisciplinary approach involving neurology, rheumatology, and other specialists as needed 1

Pitfalls to Avoid

• Failing to distinguish between autoimmune disease flare and lecanemab-related adverse events, which may present with similar symptoms 1, 5
• Overlooking the increased risk of infection in patients on both immunosuppressants and lecanemab 5
• Not considering drug interactions between immunosuppressants and other medications needed for dementia management 1