Is donanemab safe?

As well as testing the effectiveness of donanemab, the clinical trial also tested the safety of the drug, with monitoring for bad side effects.

As with all drug treatments, there have been some side effects associated with donanemab. 

These included headaches, reactions to the intravenous drip, and swelling or microbleeds in the brain known to be related to amyloid.

The vast majority of side effects (82.4%) were either mild or were detected in tests but didn’t cause any symptoms 

Unfortunately, there were three deaths (0.4% of participants) in the trial related to brain swelling and 1.6% of participants had serious symptoms relating to brain swelling. 

Safety will be carefully considered alongside the benefits of the drug by regulatory authorities.

They will decide whether the drug should be made available to people with early stage Alzheimer’s disease.

How does donanemab work?

Donanemab is given to patients intravenously, which means into a vein through a drip bag. It is an immunotherapy drug developed by a pharmaceutical company called Eli Lilly.  Immunotherapy drugs are already used in medicine for treating different diseases, like cancers. 

They tell the body’s immune system to attack foreign cells or proteins and get rid of them so they can’t cause any more problems. In the case of donanemab, it teaches the immune cells to recognise and remove a protein called amyloid, which builds up in Alzheimer’s disease. 

The amyloid protein build-ups are thought to be toxic to brain cells, causing them to get sick and eventually die, leading to the symptoms of Alzheimer’s disease. 

Three-quarters of the people taking donanemab had amyloid successfully cleared from their brains by the end of the trial.

When might donanemab be available in the UK?

To be available for use in the UK, a drug needs to be approved for use by the Medical and Healthcare Products Regulatory Agency (MHRA) But this only allows it to be legally used in the UK. We expect to hear a decision from the MHRA about donanemab later in 2024.

For it to be available on the NHS it will then also need to be reviewed by the National Institute of Health and Care Excellence (NICE), this decision is due in September 2024

They will consider the cost-effectiveness of donanemab, as well as the benefits and side effects.

This means that if decisions are positive, the very earliest donanemab might be available on the NHS is 2025.