However, its use is restricted to individuals with one or no copies of the APOE4 gene variant, which is linked to a higher risk of severe side effects.

Recent studies indicate that Leqembi increases the risk of amyloid-related imaging abnormalities (ARIA), with ARIA-E risk at 8.9% and ARIA-H at 12.9% in the approved patient group.

Severe side effects, including brain swelling and microbleeds, necessitate careful monitoring, particularly in elderly patients who comprise the majority of Alzheimer's sufferers.

Strict monitoring protocols will be implemented, requiring regular MRI scans to minimize risks associated with ARIA.

Clinical trials demonstrated that Lecanemab leads to a slight reduction in symptom progression, with treated patients showing a smaller increase in cognitive impairment scores over 18 months compared to untreated patients.

Despite these findings, there are uncertainties regarding the practical significance of the drug's effects, especially for women, who show lesser benefits and higher risks of side effects.

The approval of Lecanemab highlights the ongoing debate over the balance of benefit versus risk in Alzheimer's treatments, particularly given the potential for serious side effects.

The annual cost of Lecanemab therapy is estimated at around 23,000 euros, which includes treatment administration and diagnostic costs.

The drug is expected to be available in a few months but will be subject to strict regulations and requires extensive training and guidelines for healthcare providers.

The approval applies across all 27 EU Member States, as well as Iceland, Liechtenstein, and Norway, marking a significant step in the treatment landscape for Alzheimer's disease.

Leqembi (lécanemab) has been approved for treating mild cognitive impairment or mild dementia caused by early-stage Alzheimer's disease.

This approval follows a favorable evaluation by the European Medicines Agency (EMA), which determined that the benefits of Leqembi outweigh the risks for a specific patient population.