Scots could be among the first in Europe to trial the first new drug for Alzheimer's Disease in almost 20 years that may slow its progression.

The European Medicines Agency (EMA) looks set to reject the drug Aducanumab next month for widespread use in countries including the UK.

However a leading Scots dementia expert says that decision, if taken, would be the right one and could actually benefit patients.

The treatment is currently available in the United States but its approval was controversial because the trial results were inconclusive and there are some safety concerns around it's use.

Professor Craig Ritchie, who leads Scotland's dedicated dementia research centre, remains optimistic about the treatment but says further research is needed and said Scotland would be in a good position to recruit "as many patients as possible" onto trials.

HeraldScotland:

All the existing treatments for Alzheimer's Disease work by treating the symptoms but don't do anything to slow down its progression.

Aducanumab, which has been developed by Biogen for the treatment of early stage Alzheimer’s  may be the first disease modifying therapy.

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It works by breaking down the toxic build up of a protein called amyloid, which is seen in patients with the disease. Amyloid clumps together to form plaques between brain cells, interfering with their ability to talk to each other. 

Amyloid plaques seem to appear early and scientists think that getting rid of them could break the chain of events that leads to the build up of another protein called tau that damages brain cells.

The approval of the drug in June by the United States Food and Drugs Administration (FDA) was steeped in controversy because a drug company usually only asks for approval of a new treatment if they have two clinical trials which provide evidence it could benefit patients.

Prof Ritchie, Director of Brain Health Scotland, said: "I think what surprised us was the FDA decision because most people had considered that on the level of evidence presented to phase III trials, there was certainly a signal around clearing the protein but that hadn't necessarily translated in this particular population into a very clearly observed clinical benefit.

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"Most academics were pushing for phase IV trials, for research use only to see if you can tease out whether in the longer term there would be clinical benefit.

"At the end of the day, doctors like me have to be the ones to prescribe it so we were slightly concerned that the data was not that strong as it stood.

"The hypothesis, the target is right but the data from the trial wasn't strong enough to start prescribing for our patients.

"I want to see this succeed, I want to see it get to market but I think there is more work that needs to be done to complement the existing trials."

The trials also showed Aducanumab can damage to small blood vessels in the brain, which can cause headaches and increased confusion. 

"It this had been a cure, like a chemotherapy for cancer you would still have had some concerns about safety and monitoring that needs to be done."

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Prof Richie said he hopes the EMA's decision will lead to Biogen committing to a large-scale phase IV trial, potentially providing access for Scots patients. He said the treatment was only trialled on patients who were one or two decades into their diagnosis and may be more effective at an earlier stage.

"Here in Scotland with our brain health clinics we are in a very good position to get as many people as possible into those phase IV trials.

"I think from a Biogen perspective they would want that to happen sooner rather than later.

"What the field realised early on is that the best way to use drugs that target Amyloid is very, very early.

"What our brain health clinics are trying to do is pick up people at the very earliest stages because that's where we want to be doing trials and treating people.

"From a Scottish perspective, we've got the ingredients in place to help pharma develop new treatments and allow Scots patients to be the first to access them."

American charity UsAgainstAlzheimer's said it was disappointed the drug was likely to be rejected at this stage for the European market.

George Vradenburg, chair and co-founder, said: "With a negative decision the EMA would send a clear message: the door to innovation may be open in the United States but not in Europe; don’t even try.”

The Herald is backing Alzheimer Scotland's campaign for fairer care costs for people with advanced dementia.