People with Parkinson’s disease have been fitted with an implant that can deliver drugs directly to the brain through a port in the side of their head in a pioneering study.
The device was used to send a naturally occurring protein, which it is hoped may help restore cells damaged by the disease, to an affected part of the brain.
The results of the trial offers hope to patients with Parkinson’s, the researchers said.
Meanwhile, the effectiveness of the delivery system suggests it could offer new ways of treating brain tumours, strokes and other degenerative conditions.
A total of 41 people underwent robotic surgery to have four tubes placed in their brains as part of the Parkinson’s UK-funded study, carried out in association with North Bristol NHS Trust.
The specially designed system allowed a protein, Glial Cell Line Derived Neurotrophic Factor (GDNF), to be infused to the affected part of the brain with “pinpoint” accuracy.
Half the group received monthly infusions of GDNF over nine months, while the other half received placebo infusions.
All participants were then offered a nine-month course of GDNF.
The brain scans of patients who received the protein showed signs of improvement after the first stage of the trial, according to the findings published in journal Brain and the Journal of Parkinson’s Disease.
Dr Alan Whone, principal investigator, said patients had on average been diagnosed eight years previously but the scans showed images that would be expected two years post-diagnosis.
“We’ve shown with the PET scans that having arrived, the drug then engages with its target, dopamine nerve endings and appears to help damaged cells regenerate or have a biological response,” Dr Whone said.
Both groups of patients showed improvements in their symptoms after nine months, particularly those who had received GDNF, but there was no significant difference between the two.
After 18 months, when all patients had received GDNF, both groups showed moderate to large improvements in their symptoms, with many becoming more active and taking up pursuits such as cycling.
It is not clear whether this is due to the placebo effect because participants expected a benefit, the researchers said.
The improvement in brain scans “is beyond anything seen previously in trials of surgically delivered growth-factor treatments for Parkinson’s”, Dr Whone said.
“Its failure to produce the same effect on symptoms could be for a number of reasons,” he added.
“It may be that the effects on symptoms lag behind the improvement in the brain scans so a longer double-blind trial may have produced a clearer effect.
“It’s also possible that a higher dose of GDNF would have been more effective, or that participants at an earlier stage of the condition would have responded better.”
Professor Steven Gill, the neurosurgeon who designed the implant, said it is the first time it has been used in a trial.
He believes the technology could be used to administer chemotherapy to brain tumour patients or to test new drugs for Alzheimer’s and stroke patients.
“This trial has shown that we can safely and repeatedly infuse drugs directly into patient’s brains over months or years through a small implanted port that emerges through the skin behind the ear,” Prof Gill said.
“This is a significant breakthrough in our ability to treat neurological conditions such as Parkinson’s because most drugs that might work cannot cross from the bloodstream into the brain due to a natural protective barrier.”
Professor Roger Morris, from King’s College London, said: “The system developed for use here has been proven safe in practice over 80 weeks, which is a remarkable achievement.
“If intra-brain perfusion can be safely achieved for long-term drug delivery inside the brain, the range of medication that can be used to combat brain diseases – stroke and cancer as well as neurodegeneration – will be massively expanded.”