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A landmark study led from Lund, Sweden, has shown that transplanting stem-cell derived dopamine progenitor cells into the brain is feasible, marking a significant milestone for stem cell Parkinson’s therapy. Eight patients were transplanted in the first clinical trial, and no serious side effects linked to the transplanted cells were seen during the first year of follow-up. The results are published in Nature Medicine.
Why Stem Cell Parkinson’s Therapy Targets Dopamine Loss
In Parkinson’s disease, patients lose nerve cells in the brain that produce dopamine, which leads to symptoms such as slowness of movement, stiffness, gait disturbance, and tremor. The current treatments are medications that replace the lost dopamine, but over time these medications often become less effective and cause side effects, a limitation that stem cell Parkinson’s therapy aims to address directly.
How the Therapy Works
The therapy tested in the current trial aims to replace the cells that produce dopamine through transplantation of a stem cell-based dopamine nerve cell product to the brain. The goal is that after being transplanted, they will mature into new dopamine-producing nerve cells in the brain, offering a fundamentally different approach than medication-based symptom management.
Trial Design Behind This Stem Cell Parkinson’s Therapy
Eight individuals with Parkinson’s disease received the transplanted cell product at two different doses, followed by 12 months of immunosuppression to prevent graft rejection. Seven participants completed 12-month follow-up; one participant died from a pulmonary infection that was not directly related to the cell product.
Safety and Surgical Tolerance
The surgical procedure was generally well tolerated, and no graft-induced involuntary movements were observed in the transplanted participants. Clinically, patients remained stable throughout the follow-up period, an important early safety signal for this stem cell Parkinson’s therapy approach.
Early Signs of Graft Survival in Stem Cell Parkinson’s Therapy
Imaging using dopamine PET scans provided early indications of graft survival at both 6 and 12 months post-transplantation. Six of the seven participants substantially reduced their dopaminergic medication, a result that will be evaluated further over time as researchers continue tracking the therapy’s effects.
Expert Reaction to the Trial’s Progress
“This represents an exciting new departure on repairing the brain of individuals with Parkinson’s using dopamine cells, an approach pioneered in Lund some 40 years ago using fetal dopamine cells,” said Roger Barker, Professor of Clinical Neuroscience at the University of Cambridge, clinical lead of STEM-PD and clinical PI at the UK site. “The STEM-PD trial harnessing the expertise of scientists and clinicians from Lund and Cambridge has enabled us to undertake and deliver on one of the first ever stem cell-derived dopamine cell therapies for patients with Parkinson’s.”
What Researchers Say About This Stem Cell Parkinson’s Therapy
“Reaching this primary endpoint and being able to show that the cell product is safe is a great achievement for this trial, our team, the participating patients but also for all patients suffering from Parkinson’s disease,” said Gesine Paul-Visse, Professor in Neuropsychiatric Research and Lead PI at Skåne University Hospital, the Swedish clinical site where all patients were treated. “We are hopeful that the early signs of cell survival and clinical improvement we observe will continue to increase over the time and excited to continue the development of this cell therapy.”
What Comes Next
The STEM-PD research team will now continue the long-term follow-up of the participants to further evaluate safety, graft function, and clinical benefit of this stem cell Parkinson’s therapy approach over an extended timeframe.
The Scientific Foundation Behind This Stem Cell Parkinson’s Therapy
STEM-PD builds on decades of research in dopamine cell replacement therapy for Parkinson’s disease at Lund University and pioneering work in translating pluripotent stem cell technology from experimental studies into clinical evaluation. The therapy consists of dopaminergic neuron progenitors derived from human embryonic stem cells that mature into dopamine-producing neurons following transplantation into the brain.
A First-of-Its-Kind Trial in Europe
The STEM-PD trial is the first pluripotent stem cell trial approved in Sweden and the first for Parkinson’s disease in Europe, marking a significant regulatory and scientific milestone for this category of stem cell Parkinson’s therapy. “The initiation and execution of this clinical trial have only been possible through close collaboration between scientists, clinicians, GMP manufacturing teams, regulatory experts and, most importantly, the participating patients,” concludes Malin Parmar, underscoring the multidisciplinary effort required to bring this therapy from research to clinical evaluation.
