Parkinson’s UK Invests Up to £800,000 in New Trial Testing GDNF

Patricia Inácio, PhD avatar

by Patricia Inácio, PhD |

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Parkinson’s UK is paving the way for a future clinical trial that will continue to test a naturally occurring protein, the glial cell line-derived neurotrophic factor or GDNF, as a potential therapy for slowing Parkinson’s disease progression.

The new trial will follow a 2019 clinical study of GDNF, of which Parkinson’s UK was the major financial backer. While the results were inconclusive, they supported GDNF’s potential for regenerating dopamine-producing neurons in Parkinson’s and easing patients’ symptoms.

To this end, Parkinson’s UK has launched a new company, called Vivifi Biotech, that will be responsible for leading the planning and preparations to design the trial, the organization said in a press release.

Over the next two years, Parkinson’s UK will invest up to £800,000 (roughly $1.1 million) in Vivifi Biotech to help fund the new GDNF trial. The funding will be given through the charity’s drug development arm, called Parkinson’s Virtual Biotech. During this period, Parkinson’s UK will seek additional external investors.

GDNF, a protein that naturally occurs in the body, has previously been shown to support the growth, survival, and maturation of dopaminergic neurons — those that produce the neurotransmitter dopamine and are lost in Parkinson’s disease. Of note, neurotransmitters are substances produced in response to nerve signals that act as chemical messengers. Studies using animal models of Parkinson’s have supported the neuroprotective effects of GDNF.

A three-part clinical trial (EudraCT Number: 2013-001881-40), launched in 2019, assessed the safety and effectiveness of GDNF infusions in Parkinson’s patients. The study was funded by Parkinson’s UK with support from the Cure Parkinson’s Trust and in association with the North Bristol NHS Trust.

After a first safety assessment with six patients, a total of 41 people, ages 35–75, were enrolled in the study. Half were randomly assigned to receive monthly infusions of GDNF, while the other half were given a placebo. The infusions were administered for nine months through an implant that delivered the treatment directly to the brain via a port placed behind the ear.

Initial data indicated that monthly doses of GDNF into the putamen — a brain region involved in movement control that is deeply damaged in Parkinson’s — led to a significant increase of dopamine levels in the brain, compared with the placebo group. However, this had no reflection on the patients’ symptoms.

All 41 participants enrolled in an open-label extension phase, during which all of them — both those previously given GDNF or individuals on a placebo — received GDNF for nine months.

Although all patients knew they were receiving GDNF in the extension phase, they remained oblivious to what their original treatment was.

After 18 months, both groups showed a trend toward motor function improvement. However, there still were no significant differences seen in the “off” state of the Unified Parkinson’s Disease Rating Scale (UPDRS) motor score — the trial’s main goal — between patients who received GDNF for 18 months and those who received it for nine months only (those in the study’s original placebo group). “Off” state is characterized by the reappearance or worsening of Parkinson’s symptoms due to the diminishing effects of levodopa therapy.

Relative to the start of the trial, however, the mean total off time per day decreased by an average of 1.5 hours in patients who received GDNF throughout the whole study. Meanwhile, in those given a placebo and then GDNF, the reduction was only 0.8 hours.

These were considered encouraging results by patients who participated in the trial.

“My outcome was as positive as I could have wished for, I feel the trial brought me some time and has delayed the progress of my condition,” said Tom Phipps, one participant.

Moreover, according to Parkinson’s UK, the results suggested that the treatment may have long-term beneficial effects. Some participants told the organization that they are still experiencing the benefits of GDNF treatment.

For the new trial, Vivifi Biotech has signed an agreement with MedGenesis, the company that was leading the development of GDNF. That agreement gives Vivifi the full rights of all clinical data, patents, and know-how owned by MedGenesis.