Second lab-grown dopamine cell therapy reports its first year of human safety data

The STEM-PD trial, an academic program based at Lund University and the University of Cambridge, has published 12-month safety and feasibility results for an off-the-shelf dopamine progenitor cell product in eight people with Parkinson's disease, giving the field a second, independent line of early human evidence.

A phase 1/2 open-label trial called STEM-PD has reported 12-month safety data on a cryopreserved, off-the-shelf dopaminergic progenitor cell product transplanted into the brains of eight people with Parkinson's disease, according to a paper published in Nature Medicine and data presented at the ISSCR 2026 Annual Meeting in Montreal. The trial, run by researchers at Skane University Hospital, Lund University, the University of Cambridge and reNEW at the University of Copenhagen, in collaboration with Novo Nordisk, met its primary endpoint: no serious side effects directly linked to the transplanted cells were reported in the first year, according to Lund University's own account of the results. Seven of the eight participants completed the 12-month follow-up; one participant died of a pulmonary infection that investigators said was not related to the cell product, per the university's report.

The cells used in STEM-PD are dopaminergic neural progenitors derived from a human embryonic stem cell line, delivered by injection into the putamen, the brain region most affected by the loss of dopamine-producing neurons in Parkinson's disease. Participants received one of two cell doses and were given 12 months of immunosuppression to prevent the graft from being rejected. Beyond safety, the researchers reported biological activity: PET brain imaging indicated the transplanted cells survived in patients' brains, and Lund University's report states that six of the seven completed participants showed signs of reduced need for dopamine medication, according to a University of Copenhagen account of the same data.

The result matters because it is a second, independently developed cell product reaching a comparable milestone in Parkinson's cell therapy, distinct from the bemdaneprocel program covered elsewhere in this section. Researchers themselves frame this as an early step: the trial's own investigators wrote that STEM-PD provides confirmatory evidence alongside other recently reported pluripotent stem cell dopaminergic transplant programs, and Lund University stated the safety data allow the product to proceed toward Phase II testing. The research team said it will continue following participants to assess long-term safety, graft function and clinical benefit, and is exploring ways to reduce or eliminate the need for immunosuppression.

None of this changes what is available to patients today: STEM-PD remains an experimental, unapproved therapy tested in a small trial, and researchers say further, larger studies are needed before its clinical benefit or long-term safety can be established.