Patient enrollment completed in a neuronal cell replacement trial for Parkinson’s disease
Patient enrollment completed in a neuronal cell replacement trial for Parkinson’s disease
On July 7, Kenai Therapeutics announced that it had enrolled participants in REPLACE, an early-stage trial of the cell therapy RNDP-001. Physicians inject dopamine neuron progenitors directly into the region of the brain where Parkinson’s disease progressively destroys these cells.
Parkinson’s disease kills dopamine-producing neurons. As a result, a person finds it increasingly difficult to initiate and control movement. Medications can compensate for the dopamine deficit and reduce symptoms, but they cannot replace the cells that have died.
RNDP-001 is intended to do something different: introduce new dopamine neuron progenitors into the putamen so that they can mature, survive, and integrate into the damaged neural circuit. These cells are derived from induced pluripotent stem cells, which are adult cells returned to an early developmental state in the laboratory and then directed to become neurons. The therapy is allogeneic: it is manufactured in advance from a single cell line, frozen, and prepared as a standardized product for multiple patients.
The trial registry lists 12 participants and three sequential dose groups. The primary assessment continues for 15 months after transplantation. During this period, physicians collect data on adverse events and patient withdrawals. They then assess whether the amount of time during which medication keeps movement under control changes, along with the dopamine system signal measured by L-DOPA PET, an imaging method that shows the activity of dopamine neurons in the brain.
One-year results from another cell therapy program for Parkinson’s disease have already shown PET evidence that transplanted neurons survived, but they left two questions unanswered: whether movement will improve and what the immune cost will be. REPLACE examines the same sequence step by step. The cells must be delivered safely to the brain, survive after transplantation, integrate into the neural network, and produce changes that can be linked to the patient’s movement.
Kenai announced the completion of enrollment on July 7. The latest registry status update was published on January 23 and still lists the study as recruiting. The new enrollment status has not yet been entered there. The first protocol data will become available after the patients have been followed, and the estimated primary completion date is September 2027.