The European Medicines Agency (EMA) has refused approval for Aduhelm, a medicine intended to be used to treat Alzheimer’s disease. The agency said that the benefits of Aduhelm would not outweigh the risks, which is why it should not be approved for the time being.
The drug was developed by the US biotechnology company Biogen. It is based on the active ingredient aducanumab, a monoclonal antibody that is directed against amyloid and is supposed to reduce deposits in the brain that are associated with Alzheimer’s disease. It is intended for the treatment of patients in the early stages of the disease, namely Alzheimer’s-related mild cognitive impairment (MCI) and mild dementia.
In the United States, the FDA had already approved the drug in an accelerated process in June 2021. The reason was that the need for Alzheimer’s therapy was so great that the benefits would outweigh the risks. The clinical studies had shown a connection between the administration of Aduhelm and the reduction in amyloid, which would suggest that an early administration of the drug should also have a positive effect on the containment of the disease. But the drug was and remains controversial.
Alzheimer’s disease – progressive brain disease
According to the German Alzheimer’s Society, around 1.7 million people live with dementia in Germany, around two thirds of them have Alzheimer’s. Because nerve cells in the brain die, people with Alzheimer’s disease become increasingly forgetful, confused and disoriented. How exactly the disease develops has not yet been fully clarified.
Two different protein deposits seem to play an important role: plaques made from beta-amyloid and fibrils made from tau. In the healthy brain, the protein is broken down and broken down without any problems. If this process is disturbed, beta-amyloid proteins (Aβ) are created, which in turn clump together between the nerve cells over time. These deposits are also called ß-amyloid plaques or simply plaques. The tau protein, on the other hand, is not located outside, but inside the cells, where it is responsible for the stability and supply of nutrients.
Alzheimer’s disease chemically changes the tau protein. Similar to plaques, it is then deposited in the form of fibers: the cells lose their shape, their functions and disintegrate. The loss of nerve cells leads to typical Alzheimer’s symptoms such as forgetfulness and disorientation. Inflammatory processes also seem to be involved in the development of the disease. About one percent of Alzheimer’s cases are hereditary.
“The results of the most important aducanumab studies were contradicting”
The FDA approval was preceded by an almost unanimous vote by an independent advisory committee, which rejected the drug because the benefits had not been clearly proven. There had been two studies for Aduhelm, both of which were terminated prematurely after a negative interim analysis. And even if one of the two studies still indicated effectiveness in the final evaluation, the data were not convincing, judged the committee.