A regenerative approach to treating Parkinson’s disease — featuring an implant to pump a protein directly into patients’ brains — floundered on its first clinical test, but that hasn’t stopped researchers in the UK from holding out hope that it can eventually work by restoring damaged brain cells.
Championed by Parkinson’s UK, the treatment works by boosting the levels of GDNF, or glial cell line derived neurotrophic factor, a naturally occurring protein thought to protect cells and help them recover or regrow. To receive the protein — which is too large to penetrate the blood-brain barrier — patients first have to undergo a robot-assisted surgery to have four tubes placed into their brains, then get hooked to a machine that infuse GDNF to precise locations of the brain via a port on the side of the head.
After confirming safety with six patients, scientists recruited 35 more patients to see if infusing GDNF this way led to improvements in Parkinson’s symptoms, from motor movements to daily activities.
The short answer is no: The “encouraging signs of improvements” among patients in the drug arm did not constitute a significant difference from the placebo group.
But principal investigator Alan Whone was quick to offer potential explanations, namely the short double-blind trial time (nine months), the relatively low dosage of GDNF, and the stage that patients were already at by the time they enrolled.
His optimism is backed up by some evidence that GDNF had promising effects on brain cells already ravaged by the disease — showing a 100% improvement in a key area of the brain affected in the condition compared to placebo, which didn’t induce any change.
“The spatial and relative magnitude of the improvement in the brain scans is beyond anything seen previously in trials of surgically delivered growth-factor treatments for Parkinson’s,” Whone said in a statement. “This represents some of the most compelling evidence yet that we may have a means to possibly reawaken and restore the dopamine brain cells that are gradually destroyed in Parkinson’s.”
Furthermore, a nine-month follow-up period during which the placebo group also switched to GNDF saw all participants demonstrating “moderate to large improvement in symptoms” compared to their own baseline scores, bolstering the hope that the effects on symptoms were just lagging behind improvement in brain cells.
All of this spells “exciting signs of promise” for device manufacturer Renishaw as well as MedGenesis, the biotech developing GDNF and diving into an increasingly crowded field with plenty of smaller players tied up with big partners, touting new technologies like protein degradation to gene therapy.
“We believe this experimental Parkinson’s Disease Composite Response (PDCORE) may better capture the full effects of GDNF and we’re working to get it scientifically validated so that it can be used in future trials,” CEO Erich Mohr said.
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