The European Medicines Agency (EMA) is preparing to make a crunch decision on aducanumab, with a verdict expected on December 17. If granted a licence, it would be the first new treatment for 20 years and the first to tackle the underlying causes of the harrowing condition. Professor Bart De Strooper, director of the UK Dementia Research Institute, said: "If the EMA decides not to approve aducanumab it is likely the UK will follow suit.

       "This would be disheartening for so many individuals and scientists, but I believe these developments represent a turning point in our race to find cures. There is real momentum in the field and, with sustained investment, I am hopeful for life-changing treatments in the not-so-distant future."

       If rejected, the decision will spark huge controversy over a drug that has already split the medical community. Aducanumab was approved for medical use in the US in June. But the decision triggered the resignation of three Food and Drug Administration advisers, citing a lack of evidence that the drug is effective.

       The EMA's decision will determine whether the drug comes before the UK regulator, which sanctioned the world's first Covid vaccines last year. Aducanumab, an antibody developed by pharmaceutical giant Biogen, is given intravenously and works by breaking down the toxic build-up of a protein called amyloid.

       Amyloid clumps together to form plaques between brain cells, interfering with their ability to communicate with each other. Scientists think clearing the plaque at an early stage may stop the build-up of a protein called tau that damages brain cells.

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       THERE'S no doubt the EMA's decision on aducanumab will spark huge emotion for the thousands living with early Alzheimer's in Europe. Many in the UK will be holding their breath too. Until the decision, we don't know whether that emotion will be hope or frustration.

       In recent years, people with Alzheimer's have witnessed several potential new treatments fall at the final hurdle.

       For families devastated by the disease, the 20-year wait for new treatments has been agonisingly long.

       The EU regulator will decide whether there is enough evidence that aducanumab is safe and brings the benefits people with Alzheimer's expect and deserve.

       Catalyst

       If approved, it could pave the way for similar landmark decisions for people in the UK early next year. But the decision will not be without controversy.

       The clinical trials for aducanumab were stopped early, and many doctors and researchers are concerned about a lack of evidence that the benefits of the drug outweigh any risks. Early indications from the EMA advisory committee suggest they may rule against recommending it in the EU on this basis.

       EU and UK regulators will expect to see clear evidence of benefits before approving any drug. Next week's decision must be a catalyst for urgent action. The pandemic has shown the UK can be a world leader in fast-tracking access to Covid-19 vaccines in a safe and effective way.

       We must learn all we can from that to ensure people with Alzheimer's get access to cutting-edge treatments as soon as possible.

       Hilary Evans is chief executive of Alzheimer's Research UK