This is a robustly conducted and innovative trial. The results are exciting and mean that over the next year or two we may well be able to offer patients a choice of treatments that slow down progression of Alzheimer’s disease. Some patients did not worsen significantly during the trial and on average progression of disease was slowed 4.4-7.5 months over 18 months. The drug seems to have a meaningful benefit, at least for some patients. 

We do not yet know whether this benefit would continue after 18 months. 

There were significant side effects and patients will need to be aware of risks of treatment so they can choose whether they take these drugs or not. 

These data start to show how we can tailor treatment to patients who will benefit most (i.e. those with evidence of amyloid without very high levels of tau) – and how we can limit the dosing of medication. This is very important in clinical practice, especially as there are side effects and costs may be significant. 

However, the resource implications of taking this sophisticated approach are enormous. We need to transform our access to brain scans and infusion suites and train a skilled workforce to deliver these treatments. Alzheimer’s is a common condition, and we want people to be eligible for treatment on the basis of need, rather than access being limited to those who can afford private care or live in certain areas of the country.

The results add further evidence that immune therapies that successfully remove amyloid plaques associate with modest slowing down of Alzheimer’s disease progression. The study is well conducted and notable for the further evidence that therapy in earliest stages of the disease (that is where there is still low levels of tau protein build up in the brain) carries the greatest benefits. Concerns remains over the side effects of these drugs - a significant proportion of patients developed a form of brain oedema.

On a positive note, this side effect resolved without causing symptoms for the majority of patients. The next stage is to find out what the long term outcomes are of those have been on therapy - we still do not know when patients would stop treatment in the real world. This is going to have a huge importance on making the health economic case for this type of drug being made available through the NHS.

Finally, the effects in early disease raise the question of whether these therapies should be given to people who have evidence of Alzheimer’s disease in their brains but are still symptom free.