Stem Cell Therapies for Parkinson’s Are Advancing in Clinical Trials

A growing number of research groups are bringing stem cell-based therapies into clinical testing for Parkinson's disease. Here's what these advances mean for people with PD today, and what researchers still need to learn.

The loss of dopamine-producing cells in the brain is a key driver of movement symptoms in Parkinson's disease (PD). Several existing treatments, including levodopa and dopamine receptor agonists, can restore or mimic dopamine to help improve motor symptoms, but these treatments do not replace dopamine neurons.

Cell replacement therapy aims to address that gap by surgically transplanting new dopamine-producing cells into the brain. Stem cells are being explored as a source of these cells. Researchers have been studying cell replacement therapy for PD for decades, but recent advances in stem cell science have generated renewed interest in the approach.

Early Stem Cell Discoveries

The promise of stem cells lies in their profound ability to divide and develop into other cell types. A breakthrough in stem cell research occurred in the early 2000s, when researchers developed a way to take adult cells, like skin cells, and reprogram them into a stem cell-like state. These cells, termed induced pluripotent stem cells (iPSCs), can develop into nearly any cell type. This discovery unleashed a whole new wave of progress in stem cell research.

The Michael J. Fox Foundation (MJFF) was a key supporter of this foundational stem cell research and advocated for policies that allowed researchers to responsibly study stem cells and investigate their potential as therapies.

Recent Steps Forward

Much of the recent enthusiasm around stem cell therapies in Parkinson's comes from two critical advances. Researchers can now reliably coax stem cells into becoming dopamine-producing brain cells, and some of MJFF's earliest funding supported this line of research. In addition, early clinical studies suggest that these stem cell therapies can be safely manufactured and delivered to patients. Larger trials involving more participants are now needed to confirm safety and directly evaluate how effective these experimental therapies may be at treating motor symptoms.

Stem Cell Therapies Now in Clinical Trials

Here's a sampling of stem cell-based dopamine neuron replacement therapies currently being tested in clinical trials in the U.S. More information on these and other trials is available at Fox Trial Finder. Talk with your doctor for guidance on which study is best for you.

• Aspen Neuroscience is developing Sasineprocel (ANPD001), an investigational cell therapy for Parkinson's disease made from a patient's own cells, which are reprogrammed into stem cells and then developed into dopamine-producing neuron precursors. Sasineprocel is currently being evaluated in the Phase I/IIa ASPIRO clinical trial. Aspen is preparing to initiate its Phase III clinical trial, INSPIRE-PD, with biopsy collection from participants anticipated to begin by the end of 2026.
• Bemdaneprocel, developed by BlueRock Therapeutics, is an investigational cell therapy made of iPSC dopamine neuron cells. It is being evaluated in a Phase III clinical trial, exPDite-2. The study is expected to enroll 102 participants who were previously treated with dopamine therapy and are experiencing motor fluctuations to test the drug's ability to improve motor symptoms. Phase III testing is the final stage before a therapy can be submitted to the FDA for approval.
• DSP-1083, an allogenic iPSC-based therapy developed by Sumitomo Pharma America, is in Phase I/II testing. The trial will assess the therapy's safety and plans to enroll approximately 25 people with PD. A version of the product from Sumitomo Pharma, raguneprocel, received conditional approval in Japan in March 2026. Raguneprocel is not currently approved for patients in the U.S.
• NouvNeu001, an allogeneic iPSC-based therapy from iRegene Therapeutics, is in Phase I/II testing. The study is expected to enroll about five patients and will primarily evaluate safety.
• RNDP-001, an allogenic iPSC-based therapy developed by Kenai Therapeutics, is being evaluated in a Phase I/II trial that completed enrollment of 12 patients in July 2026.
• An autologous iPSC therapy from Oryon Cell Therapies developed by researchers at Mclean Hospital in Belmont, Mass., is in Phase I/IIa testing. The study is expected to enroll 12 patients.

Still Experimental, With More Results to Come

For now, these therapies remain experimental and are not approved treatments for Parkinson's. Also, in their current form, they don't represent a cure for the disease. Rather, they may provide an additional source of dopamine to help alleviate some motor symptoms - somewhat like the wearable pumps that deliver dopamine under the skin, but in the brain.

As stem cell-based therapies progress through clinicals trials, researchers will be working to answer several key questions, including whether these therapies provide meaningful clinical benefit, what the best delivery methods are, how long the treatment effects may last and which patients may be most likely to benefit. It will likely take several years for enough data to be collected to have a clear understanding of what role stem cell therapies may play in Parkinson's treatment.

Patients interested in participating in clinical research can consult with their doctor and review MJFF's Fox Trial Finder or clinicaltrials.gov to find available trials.

The medical information contained in this article is for general information purposes only. The Michael J. Fox Foundation has a policy of refraining from advocating, endorsing or promoting any drug therapy, course of treatment, or specific company or institution. It is crucial that care and treatment decisions related to Parkinson's disease and any other medical condition be made in consultation with a physician or other qualified medical professional.

This resource was brought to you with support from Aspen Neuroscience, BlueRock Therapeutics and Sumitomo Pharma America. Partner support allows us to furnish high-quality educational content to the Parkinson's community while allocating donor dollars to high-impact research. The Michael J. Fox Foundation is solely responsible for the content on this page.