The therapy, developed by US pharmaceutical company Voyager Therapeutics, aims to use genes to treat those in more advanced stages of Parkinson's.
How does it work?
Levodopa is a chemical building block that your body converts into dopamine - the chemical that is lost in people with Parkinson's.
It's one of the main drugs used to treat Parkinson's but it can become less effective as the condition progresses.
It's still early days but this treatment offers significant promise for helping current Parkinson's medications work better for longer.
In people with more advanced Parkinson's it can be harder to convert levodopa to dopamine as they have lower levels of a key enzyme, called AADC.
The new gene therapy treatment, called VY-AADC01, aims to increase the levels of this crucial enzyme which people with Parkinson's lack so that they can produce dopamine more easily.
About the trial
In this early stage (Phase 1b) trial, 10 people with advanced Parkinson's received an injection of VY-AADC01 into the area of the brain affected by Parkinson's.
The results showed that the group who received the highest dose of the treatment responded better to levodopa and were even able to reduce their medication after six months.
The study also reported increased activity of AADC enzymes in the part of the brain affected by Parkinson's after six months.
The company are now planning a larger study - including a placebo group who won't receive the treatment - towards the end of 2017.
What happens next?
Sophie Mclachlan, Research Communications Officer at Parkinson's UK, said:
"Although levodopa is effective in managing Parkinson's symptoms, as the condition progresses people require more medication as it may not work as well.
"We're pleased to see that larger studies are already being planned for 2017 and will keep a close eye on further developments.
"This treatment uses a technique called gene therapy to help brain cells to convert the drug levodopa into dopamine – a process which gradually stops working properly as Parkinson's progresses.
"It's still early days but this treatment offers significant promise for helping current Parkinson's medications work better for longer.
"We're pleased to see that larger studies are already being planned for 2017 and will keep a close eye on further developments."