Parkinson’s Clinical Stem Cell trials recruiting now in the US

What They’re Testing

• The trial is testing RNDP-001, a dopamine-producing stem cell therapy.
• The cells are allogeneic iPSC-derived cells, created by reprogramming adult donor cells.
• They are designed to replace dopamine-producing neurons lost in Parkinson’s disease.
• Loss of dopamine causes symptoms such as tremor, stiffness, and slowed movement.

How the Stem Cells Are Used

• The cells are surgically implanted directly into the brain.
• They are placed into the putamen, a key brain region involved in movement.
• The study is open-label and not randomized — everyone receives the treatment.

Dosing Strategy

• Cells are delivered during brain surgery using a precision syringe device.
• Participants are treated in staged dose groups:
• Low-dose group
• Higher-dose group
• Final group receiving the dose judged safest and most appropriate
• This approach is designed to maximize safety.

Safety Checks & Monitoring

• This trial focuses primarily on safety.
• Doctors monitor for side effects, surgical complications, and serious medical events.
• Any need to pause or stop treatment is carefully recorded.
• Participants are followed for at least 15 months after transplantation.
• Monitoring includes neurological exams and brain imaging.

What They’re Measuring

Primary Goal

• Safety and tolerability of the stem cell transplant.

Secondary Goals

• Changes in “ON time”: how long Parkinson’s medications work well each day.
• Dopamine activity: measured using PET scans with L-DOPA.

Study Timeline

• Study Start: July 2025
• Primary Results Expected: September 2027
• Full Study Completion: June 2031
• The long follow-up helps assess long-term safety.

What They’re Testing

• This trial is testing whether it is safe to implant new dopamine-producing brain cells made from each patient’s own skin cells.
• Parkinson’s disease happens when the brain loses the ability to make enough dopamine, a chemical that controls movement.
• This study aims to replace the lost dopamine cells using a person’s own cells, reprogrammed into early dopamine-producing neurons.
• These cells are injected into both sides of the brain in a region called the putamen, which is responsible for movement control and is heavily affected in Parkinson’s.

Dose Groups

• Low dose: 4 million cells per side of the brain
• High dose: 8 million cells per side

How the Stem Cells Are Made

• Doctors collect a small sample of skin cells from each patient.
• These are turned into iPSCs, a type of stem cell made by “reprogramming” adult cells to become like embryonic cells again.
• The iPSCs are then guided in the lab to become dopaminergic progenitor cells, early-stage brain cells that can eventually make dopamine.

Safety Checks & Monitoring

• Participants will be followed closely for 2 years after surgery.
• Doctors will check for side effects from the cell transplant.
• Problems related to the surgery.
• Any serious adverse events.
• Brain scans (PET, MRI, CT) will be used to track how the cells behave in the brain.

What They’re Measuring

Primary Goal

• Safety and tolerability: Doctors will record all side effects and serious health problems after the transplant.

Secondary Goals

• Brain dopamine activity: Measured with special PET scans.
• Motor function: Measured using a Parkinson’s symptom scale (MDS-UPDRS Part III).
• “Off” hours: How many hours a day symptoms return despite medication.
• Dyskinesia: Severity and frequency of involuntary movements.
• Medication use: Any changes in how much Parkinson’s medication is needed.
• Quality of life: Based on a questionnaire (PDQ-39).
• Global impression of change: Judged by both the patient and their doctor.

Timeline

• Study Start Date: April 2025
• Primary Results Expected: December 2027
• Study Ends: December 2028

What They’re Testing

• The treatment being studied is called Bemdaneprocel.
• It’s an advanced stem cell therapy that aims to replace lost dopamine-producing brain cells.

• Grown from human embryonic stem cells
• Carefully guided in the lab to become dopaminergic neuron progenitors, early-stage cells that can make dopamine
• Surgically implanted into the brain region called the putamen, which controls movement

Because Parkinson’s disease destroys the brain’s ability to make dopamine, this therapy is designed to rebuild those lost circuits, potentially reducing symptoms and medication needs.

Study Design

• This is a randomized, placebo-controlled, double-blind study meaning:
• Participants are randomly assigned to either receive Bemdaneprocel or undergo sham surgery (a procedure that mimics surgery without actual treatment).
• Neither the patient, the care team, nor the symptom assessors know which treatment the patient received.
• All participants are given either real immunosuppressive drugs or placebo versions for 12 months, to help protect the implanted cells or maintain blinding.
• After 18 months, some patients in the sham group may be offered real treatment.

Safety Checks & Monitoring

• All participants are monitored for up to 5 years.
• Reports of side effects and serious medical events.
• Brain imaging (PET/MRI).
• Long-term follow-up by doctors and researchers.

What They’re Measuring

Primary Goal

• Change in ON-time (without troublesome dyskinesia): How many more hours per day participants have good symptom control after treatment, based on a Parkinson’s diary (Measured up to 78 weeks after treatment).

Secondary Goals

• OFF-time: How much time symptoms return despite medication.
• Motor function (MDS-UPDRS Parts II & III): Ratings of movement ability, tremors, stiffness, etc.
• Quality of life (PDQ-39).
• Adverse events (side effects): Followed for up to 60 months (5 years).

Timeline

• Started: June 2025
• Primary Results Expected: March 2027
• Final Study Completion: March 2032 (Patients will be followed long-term)

Previous Results

Before this larger Phase 3 trial, a small group of people took part in an earlier study testing the same treatment.

These patients received bemdaneprocel and were followed for up to 3 years.

Here’s what the early results showed after 36 months:

• No major safety problems were linked to the treatment or the surgery.
• The transplanted cells survived in the brain and stayed active, even after patients stopped taking immune-suppressing drugs.
• People who got the higher dose showed promising trends in movement improvements, which stayed stable or improved over time.
• These results gave researchers confidence to move into this larger Phase 3 study.

This longer follow-up helps doctors understand how the treatment works over time and gives early clues about its long-term safety.

What They’re Testing

• This trial is testing whether it is safe and potentially helpful to transplant new dopamine-producing brain cells into people with Parkinson’s disease.
• Parkinson’s disease happens when dopamine-producing cells in the brain gradually die.
• Dopamine is essential for smooth, controlled movement.

In this study:

• Doctors implant new dopamine-producing cells directly into the brain.
• The cells are placed into both sides of the putamen, a brain area critical for movement.
• The goal is to see if the cells are safe, survive in the brain, and may help improve symptoms over time.
• There is no placebo group in this trial. Everyone who joins receives the treatment.

How the Stem Cells Are Made

• Doctors take adult cells from a donor.
• These adult cells are reprogrammed into iPSCs (induced pluripotent stem cells).
• iPSCs are stem cells that can turn into many different cell types.
• In the lab, these iPSCs are guided to become dopaminergic progenitor cells, early brain cells that can develop into dopamine-producing neurons.
• This treatment is allogeneic (not made from the patient’s own cells).

Cell Dose & Surgery

• Each participant receives approximately 4.2 to 5.4 million cells per side of the brain.
• Cells are injected into both sides of the putamen.
• Surgery is performed using a precision brain injection device attached to a stereotactic frame for accuracy.
• All participants are followed closely for 24 months after surgery.

Safety Checks & Monitoring

• Safety is the main focus of this study.
• Doctors closely monitor graft expansion (whether the transplanted cells grow abnormally).
• Any side effects or serious medical events.
• Brain imaging using MRI and PET scans at multiple time points.
• Clinical exams and symptom tracking over 2 years.
• Special attention is given to detecting abnormal tissue growth, which is a known concern with stem cell therapies.

What They’re Measuring

Primary Outcomes (Most Important)

• Safety: Any treatment-related side effects or serious events.
• Graft expansion: Whether transplanted cells grow larger than expected in the brain.

Secondary Outcomes

• Motor symptoms: Changes in Parkinson’s movement scores (ON and OFF medication states).
• Daily ON and OFF time: How long symptoms are controlled each day.
• Dyskinesia: Changes in involuntary movements.
• Medication use: Changes in levodopa dose needed.
• Quality of life: Based on patient-reported symptom scores.
• Brain imaging: PET and MRI scans to track cell survival and activity.

Timeline

• Study Start: June 2024
• Final Study Completion: May 2028
• Participants are followed for 2 full years after surgery.