The European Medicines Agency (EMA) has given the green light for Leqembi, an Alzheimer’s drug from US biotech firm Biogen and Japan’s Eisai, allowing its restricted use within the European Union. A recent evaluation determined that the benefits of Leqembi in slowing cognitive decline outweigh the risks for a specific subset of patients, although it remains associated with serious side effects.
Leqembi, scientifically known as lecanemab, is an antibody therapy aimed at slowing Alzheimer’s progression by targeting and reducing brain deposits of beta-amyloid, a protein linked to the disease’s neurodegenerative effects. This approach marks a shift from traditional Alzheimer’s treatments, which only alleviate symptoms without altering the disease's course. In clinical trials, Leqembi was found to reduce cognitive decline by 27% in patients in the early stages of the disease.
However, Leqembi poses significant risks, particularly for patients carrying two copies of the ApoE4 gene—a genetic marker for Alzheimer’s that raises the likelihood of a serious side effect: brain swelling and potential bleeding. The EMA’s Committee for Medicinal Products for Human Use (CHMP) has therefore recommended that Leqembi be prescribed only to patients with one or no copies of the ApoE4 gene, reducing their risk of adverse reactions.
Patients who are prescribed Leqembi will participate in a controlled access program to ensure adherence to the EMA’s restrictions. As part of this program, patients will be required to undergo regular MRI monitoring to detect any early signs of brain swelling. The EMA had previously rejected a broader use of Leqembi, concluding that the risk of severe side effects did not justify its benefits in a larger patient group.
If the EU Commission formally approves the drug, Leqembi will be the first treatment in Europe designed to slow the progression of Alzheimer’s rather than merely managing symptoms. Given that an estimated seven million Europeans live with Alzheimer’s, the availability of Leqembi could represent a significant, albeit cautious, advance in the treatment of the disease.
The approval of Leqembi has sparked debate among healthcare professionals, as its ability to delay cognitive decline does not equate to a cure.
