Will the NHS ever cover the cost of a new generation of Alzheimer's drugs?

The first drug proven to slow brain destruction in Alzheimer's disease will no longer be available through the British NHS following a decision by the Medicines Agency.

The decision to fund lecanemab has caused excitement and disappointment among those who had hoped the drug could help fight a terrible and devastating disease.

But the decision does not come as a surprise.

Lecanemab is not a “miracle drug.” The European Medicines Agency examined the same data as the UK and concluded that the drug should not be prescribed to anyone outside of a clinical trial.

But what would it take for the cost of a drug to slow Alzheimer's disease to be covered by the NHS?

The National Institute of Health and Care Excellence is tasked with finding the best way to spend taxpayers' money, balancing emotions, pressing needs and lobbying for treatments with sober, hard calculations of cost-effectiveness.

In the past, dementia drugs have been approved to help relieve symptoms such as confusion.

However, this is the first time that a drug has been tested that alters the course of the disease. This is a more familiar experience in other diseases. Earlier this summer, the cancer drug Enhertu, which can prolong the lives of some people with incurable breast cancer, was rejected because it was too expensive.

But also very expensive medicines – I reported on a one-time gene therapy The project officially costs £2.6 million – it can be approved if the benefits are large enough.

There are problems with lecanemab regarding its effectiveness, its cost and also its safety.

It was lauded for being the first drug to slow the progression of Alzheimer's disease. For a field that has faced repeated failures, the publication of the data in 2022 was a truly momentous moment. But as I wrote at that timethe effect is small.

Lecanemab cannot cure, reverse or stop Alzheimer's disease. It only slows the progression of the disease.

In studies, the disease continued to rob patients of their brain power, but that decline slowed by about a quarter over the course of 18 months of treatment. On an 18-point scale ranging from normal to severe dementia, patients who received the drug fared 0.45 points better.

How significant these effects are is still hotly debated among researchers.

Some argue that they give people vital independence for longer. Others claim the effects are so small that a doctor would not be able to tell the difference between a patient receiving lecanemab for 18 months and another receiving a placebo (dummy treatment). Still others say that patients should be allowed to make an informed choice about what is important to them.

The data on the drug came from a large-scale experiment The study involved 1,795 volunteers with early-stage Alzheimer's, but the participants were healthier and younger than people typically diagnosed with the disease. This raises questions about the drug's “real-world” effectiveness in older, frailer people with multiple health problems and even “mixed” dementia, which can be partly Alzheimer's and partly another disease.

A more effective drug with a more significant impact on the course of Alzheimer's disease could disrupt these cost-benefit calculations.

This could still potentially be lecanemab. It is possible that starting treatment even earlier or continuing treatment for longer would have greater effects. This has not yet been proven.

Or it could be that lecanemab leads the way and a future drug following in its footsteps will provide greater benefit. Medical research often needs the first breakthrough that others can build on. The first HIV drugs, after all, paved the way for modern antiretroviral therapy, which allows people to live a near-normal life expectancy.

Cost is the other side of this equation. A cheaper drug has to do less to achieve this value for money.

Lecanemab is expensive. The drug itself costs around £20,000 per patient per year (based on US prices), but the associated care doubles that cost on the NHS (and private charges are likely to be even higher).

To confirm that the patient actually has Alzheimer's disease – since there are many types of dementia – so that they can begin treatment, an expensive PET (positron emission tomography) scan or a lumbar puncture to take a sample of cerebrospinal fluid is required.

Afterwards, an infusion into a vein is required every two weeks, and further costly brain scans are needed to monitor known side effects.

One option is to negotiate a better price. As new drugs like donanemab come to market, there will be competition that could lead to price reductions.

There is still time for this to happen. NICE presented its draft decision on Thursday, which is due to be finalised later this year.

However, pharmaceutical companies want to recoup the costs they have invested in research and development over the years – and many expensive duds and dead ends have arisen in this area.

Both lecanemab and donanemab are very expensive drugs called monoclonal antibodies, which are lab-made versions of the antibodies your immune system naturally produces to fight disease.

To treat Alzheimer's disease, they are designed to attack a sticky protein called amyloid that clogs the spaces between brain cells. Amyloid is a key feature of Alzheimer's disease, and the antibodies remove it.

However, their development and production are difficult, which inevitably makes them expensive drugs. Monoclonal antibodies do not cost the same as a dose of aspirin.

The drug is also not approved for use in people who have certain genetic mutations that actually increase their risk of Alzheimer's, so genetic testing is required.

Dangers of these drugs include brain swelling and brain hemorrhages, some of which have resulted in death, so monitoring increases costs.

In theory, blood tests for Alzheimer's, drugs that require fewer infusions or have fewer side effects, or better ways to predict who is at risk of side effects could also reduce the cost of treating these drugs.

But as it stands, treating the 70,000 people who would technically be eligible for the drug in England could cost around £1.4 billion a year, and a similar amount to provide care on the NHS. This has been judged to be a poor use of taxpayers' money for a drug whose effects are widely considered to be “minor”.

Nevertheless, it is a historic week. For the first time, a drug has been approved that can slow the progression of Alzheimer's disease.

For decades, dementia was seen as an inevitable part of aging, but then it became clear that it is actually a disease. There is now optimism that we are close to being able to do something about it.