ISSCR 2026 presented 12‑month findings from the Phase I/II STEM‑PD trial of cryopreserved stem cell‑derived dopaminergic progenitors in Parkinson’s disease, highlighting feasibility, safety, and translational progress in regenerative medicine
Written By: Mayuresh Salvi, PharmD
Reviewed By: Pharmacally Editorial Team
The International Society for Stem Cell Research (ISSCR) has presented 12-month findings from the Phase I/II STEM-PD clinical trial evaluating a cryopreserved, off-the-shelf dopaminergic progenitor cell product derived from human pluripotent stem cells for patients with Parkinson’s disease. Presented during the ISSCR 2026 Annual Meeting, the study represents another milestone in the clinical translation of regenerative medicine for neurodegenerative disorders.
According to the investigators, the trial demonstrated that the investigational stem cell-derived product can be manufactured, transplanted into the human brain, and evaluated within a rigorous clinical trial framework. The 12-month analysis also generated new information on the therapy’s safety, feasibility, and biological activity. However, the ISSCR announcement did not disclose participant numbers, efficacy outcomes, adverse event rates, imaging findings, or statistical analyses from the study.
STEM-PD Evaluates a Regenerative Cell Replacement Strategy
The STEM-PD trial (NCT05635409) is a first-in-human Phase I/II study evaluating the safety and tolerability of transplanting human pluripotent stem cell-derived dopaminergic progenitor cells into patients with moderately advanced Parkinson’s disease who continue to experience significant motor symptoms despite optimized medical therapy. Secondary objectives include assessing preliminary evidence of clinical efficacy.
Participants undergo stereotactic neurosurgical transplantation of the investigational cell product into targeted brain regions affected by dopamine neuron loss. Unlike conventional pharmacological treatments that temporarily supplement dopamine signaling, the investigational therapy aims to replace the dopamine-producing neurons that progressively degenerate during the course of Parkinson’s disease.
From Fetal Tissue Research to Standardized Stem Cell Products
Cell replacement therapy for Parkinson’s disease has been investigated for several decades. Earlier clinical studies using fetal ventral mesencephalic tissue demonstrated that transplanted dopamine-producing neurons could survive within the brain and improve motor function in selected patients. However, widespread clinical development was limited by restricted tissue availability, variability between donor samples, manufacturing challenges, and ethical considerations.
Advances in human pluripotent stem cell technology have enabled researchers to generate standardized dopaminergic progenitor cells under controlled manufacturing conditions. The STEM-PD investigational product is cryopreserved and available as an off-the-shelf therapy, an approach that could improve manufacturing consistency, product quality, and future clinical scalability compared with earlier transplantation methods.
Investigators Highlight Progress in Clinical Translation
Presenting the findings, Professor Malin Parmar, Professor of Cellular Neuroscience at Lund University, Sweden, said the results represent decades of work translating stem cell biology into a clinically viable therapeutic strategy. She noted that the study demonstrates stem cell-derived dopaminergic cell products can be manufactured, delivered, and evaluated in patients within a rigorous clinical trial setting.
Parmar also said the findings reflect the broader progress of regenerative medicine from proof-of-concept research toward clinical testing in patients with complex neurodegenerative diseases. She further noted that independent stem cell-based Parkinson’s disease programs are reporting comparable safety observations despite using different cell products and clinical protocols, strengthening confidence in the overall therapeutic concept.
Path Froward for the STEM-PD Program
Investigators will continue to monitor trial participants to evaluate long-term graft survival, graft function, durability of transplanted cells, and functional integration within the brain. Future research will also examine optimal cell dosing, identify patient populations most likely to benefit, and investigate strategies to reduce the need for immunosuppression, including autologous grafts and engineered cells designed to evade immune recognition.
The 12-month findings expand the growing body of clinical evidence supporting stem cell-based dopaminergic cell replacement for Parkinson’s disease. Larger studies with longer follow-up and detailed efficacy analyses will be required to determine whether this regenerative approach can provide durable clinical benefit and ultimately become part of routine patient care.
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About the Writer
Mayuresh Sunil Salvi (Linkedin) is a PharmD professional and healthcare writer with a strong interest in pharmacovigilance, drug safety, and emerging medical research. He is passionate about exploring new drug discoveries, clinical research, and advances in evidence-based medicine. His interests also include ward rounds, prescription audits, and treatment analysis to support rational pharmacotherapy and improved patient care.