Stem cell treatment for Parkinson’s approved in Japan

What is stem cell therapy?

Over the last 40 years, we’ve invested millions in stem cell research, helping researchers understand how they could be used to repair or replace cells in the brain.

In people with Parkinson’s, the cells in the brain that produce a messenger chemical called dopamine become damaged, stop working, and are lost over time. This means that there’s not enough dopamine in the brain, and this can lead to the development of Parkinson’s symptoms.

The brain doesn’t have a way of replacing or even repairing these damaged dopamine cells. And current treatments can only tackle the symptoms of Parkinson’s. We don’t have any treatments that can replace the lost cells.

Stem cell therapies could be a solution to this. This type of therapy involves delivering stem cells, that have been given instructions to become dopamine-producing cells, directly into the brain. With the aim that they can replace some of the brain cells that have been lost, and boost dopamine production.

Therapies that involve the use of stem cells could replace lost cells, something that no current treatment can do. This could improve the movement symptoms of Parkinson’s. But they don’t treat the underlying causes of the condition. This means they’re unlikely to be able to improve some of the non-motor symptoms of Parkinson’s, like anxiety or thinking and memory problems. And the stem cells may also become damaged and lost over time.

Read more about stem cells on our research blog.

What did this research show?

The approval for this stem cell therapy, called raguneprocel, in Japan has come as a result of a successful research study.

Seven people with Parkinson’s, between the ages of 50 and 69, underwent surgery to transplant a number of stem cells in the brain. They were then closely monitored for 2 years, with regular brain scans and medical checks to make sure there were no unexpected side effects of the treatment. They were also asked to take immunosuppressant medication for 12 months, to stop the immune system attacking the transplanted cells.

At the end of the study, 5 out of the 6 participants assessed showed an improvement in their movement symptoms. Brain imaging also showed that there was more dopamine activity in the region of the brain where the cells had been transplanted. This suggested that the cells had transplanted safely and were starting to produce dopamine.

Importantly, none of the participants experienced any severe side effects.

What does this mean for stem cell therapies in the UK?

So far, the therapy has only been approved for use in Japan. Its use will be monitored for the next 7 years, where the company that makes the therapy will have to collect detailed safety information before it can be approved for longer term use.

The treatment is not available and has not been approved in the UK. However, similar stem cell therapy research trials are happening in Europe and elsewhere.

Professor David Dexter, our Director of Research, said: "The decision to grant limited, conditional approval to this therapy shows a huge step forward in stem cell research, which we’ve been actively funding for many years.

"There’s more work to be done before this might be an option for people with Parkinson’s in the UK, but this is an exciting time for stem cell research. This milestone should bring hope that we are one step closer to a new effective treatment for people with Parkinson’s."