Europe rejects a new Alzheimer's drug

BarcelonaA new milestone in the fight against Alzheimer's in Europe. The European Medicines Agency (EMA) has recommended against marketing authorization for Kisunla, a drug containing a protein called donanemab that slows the progression of the disease in its early stages. The EMA's Committee for Medicinal Products for Human Use considers that the benefits of this drug are not sufficiently large to outweigh the risks to patients. A fifteen-day period now opens during which the pharmaceutical company developing the drug, the American company Eli Lily, can request a review of the decision.

Alzheimer's is characterized by the unusual aggregation inside and outside neurons of a peptide (a protein fragment) called beta amyloid and the protein known as tabula. It is not known why this happens, but this is most likely what causes cells to break down and the brain to gradually atrophy. Donanemab is an antibody that attacks amyloid-beta protein plaques and is targeted at people suffering from early symptoms of the disease, such as mild cognitive impairment and mild dementia, as well as the presence of these plaques in the brain. This antibody has been shown in clinical studies to reduce cognitive and functional decline by up to 35%.

However, the EMA warns that other studies indicate that one in three patients may suffer from inflammation and bleeding. According to these studies, 1.6% of the people who participated suffered serious consequences, and three people died. Given this scenario, the European agency has rejected the approval of a drug that is authorized in other countries such as the United States, the United Kingdom, China, and Japan.

Precedents with lecanemab

Europe was already left alone last year when it rejected the approval of lecanemab, the first drug shown to be effective in slowing the progression of Alzheimer's symptoms. Many experts were shocked, and the EMA finally rectified and recommended that Member States authorize the marketing of Leqembi, the drug's brand name. According to several studies, this drug slows cognitive decline in people with the disease by 27%.

However, the European agency only authorized it for patients in the early stages of the disease who are genetically less likely to suffer side effects. Specifically, it is recommended for patients who have one or no copies of a gene called APOE4, and excludes those with two copies. In the case of donanemab, the pharmaceutical company proposed that it be approved under the same conditions, since patients with one or two copies of this gene have a higher risk of suffering serious side effects, but even then they have not obtained the EMA's approval.

For Robert Howard, professor of geriatric psychiatry at the Division of Psychiatry at University College London, the EMA's decision "is not surprising, as the benefits of the treatment are extremely small and would be impossible to detect in a single patient." Speaking to the Science Media Centre, the expert maintains that "the risks of the treatment are significant," but points out that the European agency already made a similar initial decision on lecanemab last year and reversed it after the manufacturer requested a review of the decision.