A stem-cell brain transplant for Parkinson’s has passed an initial safety test after eight patients received the treatment.
No serious side effects linked to the transplanted cells were recorded during the first year of follow-up.
The treatment aims to replace dopamine-producing nerve cells lost through Parkinson’s disease, potentially addressing the underlying damage rather than only easing symptoms.
The study was led from Lund, Sweden, and found that transplanting dopamine progenitor cells derived from stem cells into the brain was feasible.
Parkinson’s causes the loss of brain cells that produce dopamine, a chemical involved in controlling movement.
This can lead to slowness of movement, stiffness, walking difficulties and tremor.
Current medicines replace some of the lost dopamine, but they can become less effective over time and cause side effects.
The therapy is designed to replace the lost cells by transplanting dopamine nerve cell progenitors into the brain.
Progenitor cells are early-stage cells that can develop into more specialised cells. Researchers hope they will mature into new dopamine-producing nerve cells after transplantation.
Malin Parmar, professor of cellular neuroscience at Lund University and lead of the STEM-PD programme, said: “The possibility of replacing dopamine neurons that are lost in Parkinson’s disease has been a long-standing goal in the field.
“The findings represent an important milestone for regenerative medicine approaches in Parkinson’s disease and support continued clinical development of stem cell-based therapies.”
Eight people with Parkinson’s received the transplanted cells at one of two doses.
They then received immunosuppressive treatment for 12 months to reduce the risk of their immune systems rejecting the transplanted cells.
Seven participants completed the 12-month follow-up.
One participant died from a lung infection that was not directly related to the cell product.
The surgical procedure was generally well tolerated, and none of the participants developed involuntary movements caused by the graft.
The patients remained clinically stable.
Dopamine PET scans provided early signs that the transplanted cells had survived six and 12 months after the procedure.
PET, or positron emission tomography, uses a small amount of radioactive material to produce images of activity inside the body.
Six of the seven participants substantially reduced their dopamine-related medication, although researchers said this finding would need to be assessed over time.
Roger Barker, professor of clinical neuroscience at the University of Cambridge, clinical lead of STEM-PD and clinical principal investigator at the UK site, said: “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.
“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 and we hope this will be the beginning of an exciting new programme that may ultimately benefit the wider Parkinson’s community.”
Gesine Paul-Visse, professor of neuropsychiatric research and lead principal investigator at Skåne University Hospital, where all the patients were treated, said: “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.
“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.”
The research team will continue monitoring the participants to assess the treatment’s longer-term safety, the function of the transplanted cells and any clinical benefits.
