Donanemab (Anti-Amyloid Monoclonal Antibody)

How it works

It is a monoclonal antibody that binds to deposited amyloid-beta plaque and promotes its clearance, lowering the cerebral amyloid burden.

Prescribing in practice

• Amyloid-related imaging abnormalities (ARIA), comprising cerebral oedema and microhaemorrhage, are the key risk and require baseline and scheduled MRI surveillance, with caution in carriers of the ApoE e4 genotype.
• Confirmation of amyloid pathology and exclusion of contraindications such as significant prior haemorrhage are needed before starting, with treatment given by infusion under specialist supervision.
• Concurrent antithrombotic or anticoagulant therapy may increase the risk of haemorrhagic complications and should be carefully assessed.

Monitoring

Regular MRI monitoring for ARIA, alongside review for infusion reactions and cognitive response, is integral to treatment.

Counselling the patient

• You will need regular brain scans to check for swelling or small bleeds.
• Report any new headache, confusion, dizziness or visual changes promptly.
• Treatment aims to slow progression rather than reverse the condition.

Evidence & guidelines

Phase 3 trial evidence shows donanemab reduces amyloid plaque and modestly slows clinical decline in early Alzheimer's disease.