A dozen Alzheimer's drugs that can halt, slow or reverse the disease could be available to patients in three years, a report has revealed.
All of the 12 treatments are in late stage Phase III trials, the final hurdle before a new medicine is licensed.
If any of them live up to expectations, demand from patients will be "instant and huge", according to one leading UK dementia consultant.
And the sudden appearance of advanced, effective and costly Alzheimer's drugs could land like a financial bombshell on the NHS.
The report from dementia charity Alzheimer's Research UK warns that the Government and NHS must be ready to cope with the cost of new Alzheimer's treatments - and associated diagnostic procedures - that could run into billions.
Further down the line, experts hope to see vaccine-like preventative Alzheimer's drugs introduced within the next decade that could be given to every 50-year-old in the UK.
On its own, such an approach would cost around £9 billion per year - but could slash almost £13 billion off the overall cost of dementia to health services and the economy.
Hilary Evans (pictured), chief executive of Alzheimer's Research UK, said: "With over one million people expected to be living with dementia by 20205, we have a duty to ensure that people with dementia and their families can benefit from innovations in new treatments in the coming years.
"While our report highlights a number of challenges that could affect the roll-out of future dementia treatments in the NHS, we believe these challenges can be overcome if we act now and work together."
The charity commissioned experts at the London School of Economics to model the impact of five hypothetical Alzheimer's treatments.
But the report, entitled Thinking Differently, also highlighted progress in the real world, with 12 disease-modifying drugs due to be completing Phase III trials by 2021.
If they achieve their therapeutic goals, the new medicines will be generally available in as little as three years.
Speaking at a news briefing in London, report co-author Professor Jonathan Schott, from University College London's Dementia Research Centre, said: "The availability of new treatments for Alzheimer's disease is a when and not an if.
"Our patients are desperate for new treatments. When the media reports any hint of a new treatment for Alzheimer's disease our clinics are inundated. When we have a successful trial, and I say when, this will be headline news around the world and the demand will be instant and huge."
Currently, there is no "disease modifying" treatment available that can alter the progress of Alzheimer's. The most patients can hope for is something that, for a finite time, dampens down symptoms of the devastating disease.
But the 12 drugs coming through the pharma pipeline are disease modifying. Generally they all work the same way, by targeting sticky clumps of beta-amyloid, a protein building block that accumulates in the brain and is thought to trigger the death of neurons.
To be most effective, such drugs would have to be given as early as possible, when the first symptoms of mild dementia are showing themselves or even before. Research has shown that the seeds of Alzheimer's may begin to germinate in the brain 15 or more years before any symptoms appear.
Identifying patients who qualify for the treatments will require better diagnostics. However these are fast being developed, moving from brain scans and spinal fluid tests to blood tests.
The combination of more effective diagnostics and medicines will greatly increase the number of patients eligible for treatment.
Several vaccine-like treatments - which work more like a "statin for the brain" than a true vaccine - are currently at an earlier stage of development, undergoing Phase I and II trials, said the experts.
They could potentially be given to healthy individuals with a family history of Alzheimer's, or even a whole population of people in middle age.
Dr David Reynolds, chief scientific officer at Alzheimer's Research UK, said: "It wouldn't be an overnight scenario where everybody at 50 had a treatment like this, but that is where we're going to, I hope, in the long term."
The report said an Alzheimer's vaccine offered to more than 29 million British 50-year-olds would cost £9.4 billion per year. But an effective vaccine delaying onset of the disease for at least three years would be expected to wipe £12.7 billion off the total £26 billion per year that dementia costs the UK economy.
Copyright (c) Press Association Ltd. 2018, All Rights Reserved. Picture (c) Alzheimer's Research.