Bayer Announces Major Strides in Parkinson’s Research with Two Therapies Advancing to Key Clinical Trials

Berlin, September 22, 2025 – Global pharmaceutical company Bayer has announced significant progress in its efforts to combat Parkinson’s disease (PD), with two investigational therapies entering advanced clinical trials. A first patient has been randomized in the pivotal Phase III trial for bemdaneprocel, a cell therapy, while the Phase II trial for the gene therapy AB-1005 has begun randomizing participants in Europe.

Both bemdaneprocel and AB-1005 are aimed at treating moderate-stage Parkinson’s disease and are being developed through collaborations with Bayer’s subsidiaries, BlueRock Therapeutics and AskBio, respectively. Christian Rommel, Global Head of Research and Development at Bayer, highlighted the company’s “dual approach” of using both cell and gene therapies, stating it maximizes the potential to offer new hope to patients.

Bemdaneprocel: A Cell-Based Approach

Bemdaneprocel (BRT-DA01) is an investigational cell therapy designed to replace the dopamine-producing neurons that are progressively lost in Parkinson’s disease. The therapy uses dopaminergic neuron precursors derived from human embryonic pluripotent stem cells. These precursors are surgically implanted into the brain, where they are intended to continue developing into mature dopamine neurons. When transplanted, they have the potential to re-form neural networks that have been severely affected by Parkinson’s disease and to potentially restore both motor and non-motor function. In 2021, bemdaneprocel received Fast Track Designation, and in 2024, it received a Regenerative Medicine Advanced Therapy (RMAT) designation from the FDA.

The newly initiated exPDite-2 trial is the first Phase III pivotal clinical study for an investigational allogeneic pluripotent stem cell-derived therapy for PD. This multicenter, double-blind trial will assess the therapy’s efficacy, safety, and overall impact compared to a sham surgery control. The trial is designed to enroll approximately 102 participants, with the primary endpoint being the change from baseline to week 78 in PD diary measure of ON-time without troublesome dyskinesia. It will also include secondary endpoints to assess objective measures of movement, non-motor symptoms, safety and tolerability, and quality of life. The results from this trial are intended to be part of a data package to support regulatory submissions for marketing authorization.

AB-1005: A Gene Therapy Trial Expands

The gene therapy AB-1005 is an adeno-associated viral vector (AAV2) that delivers the human glial cell line-derived neurotrophic factor (GDNF) transgene. This allows for stable, continuous GDNF expression in the brain, a factor known to promote the survival of dopaminergic neurons in preclinical studies.

The Phase II trial for AB-1005, known as REGENERATE-PD, has expanded to Europe, with participants now being randomized in the United Kingdom and Poland. The trial is already underway in the United States and will soon include sites in Germany. Adrian Kells, PhD, from AskBio, emphasized the significance of this expansion for the patient and medical communities, underscoring the potential of neurorestorative therapies for this severe, progressive disease.

Parkinson’s Disease: A Growing Global Challenge

Parkinson’s is the second most common and fastest-growing neurodegenerative disease globally, affecting more than 10 million people. It is characterized by the death of dopamine-producing nerve cells in the brain, leading to motor symptoms such as tremors and muscle rigidity, as well as non-motor symptoms like fatigue and depression.

Currently, there is no cure, and existing treatments are considered inadequate for managing all symptoms. The advancements by Bayer in both cell and gene therapy highlight a strategic effort to develop disease-modifying therapies that could address the root causes of the disease and offer a new paradigm for treatment. It is important to note that both bemdaneprocel and AB-1005 are investigational therapies, and their efficacy and safety have not yet been fully evaluated or approved by any regulatory authority.