Bayer has announced progress on two investigational therapies for Parkinson’s disease (PD). The first participant has been dosed in the pivotal Phase III exPDite-2 trial of bemdaneprocel, an investigational cell therapy, while the first European participants have been enrolled in REGENERATE-PD, a Phase II trial of the gene therapy AB-1005. Both therapies target patients with moderate-stage PD and are being developed through Bayer’s wholly owned subsidiaries, BlueRock Therapeutics LP (bemdaneprocel) and AskBio Inc. (AB-1005).

Christian Rommel, global head of research and development for Bayer’s Pharmaceuticals Division, said, “Our dual approach of cell and gene therapies reflects our commitment to delivering innovative, disease-modifying treatments for Parkinson’s. We aim to provide renewed hope for patients who have long awaited new therapeutic options.”

Bayer is leveraging a comprehensive global infrastructure for the development, manufacture, and commercialization of advanced therapies, supported by state-of-the-art production facilities worldwide.

Bemdaneprocel (BRT-DA01) is designed to replace the dopamine-producing neurons lost in PD. Derived from human embryonic pluripotent stem cells, the dopaminergic neuron precursors are surgically implanted into the patient’s brain, where they can mature into dopamine neurons and potentially restore impaired neural networks. In 2021 the therapy received Fast Track designation and, in 2024, Regenerative Medicine Advanced Therapy (RMAT) designation from the US Food and Drug Administration (FDA). Results from a Phase I study with 12 participants showed good tolerability at 24 months post-surgery, with no serious adverse events related to the therapy and encouraging trends in motor outcomes.

The exPDite-2 trial is the first Phase III study of an allogeneic pluripotent stem cell-derived therapy in PD. This multicenter, double-blind trial aims to recruit approximately 102 participants and will assess changes in ON-time without troublesome dyskinesia at week 78 as its primary endpoint. Secondary endpoints will cover motor and non-motor symptoms, daily activities, quality of life, and safety.

AB-1005 is an investigational gene therapy using an adeno-associated viral vector (AAV2) to deliver the human glial cell line-derived neurotrophic factor (GDNF) transgene directly into the brain. This allows sustained, localized expression of GDNF, which in preclinical studies has been shown to support the survival and differentiation of dopaminergic neurons.

REGENERATE-PD is a randomized, double-blind, controlled Phase II trial evaluating the safety and efficacy of AB-1005 in adults aged 45–75 with moderate PD. The study plans to enroll around 87 participants across sites in Germany, Poland, the United Kingdom, and the United States.

Parkinson’s disease is the second most common neurodegenerative disorder worldwide, affecting over 10 million people. It is caused by the progressive death of dopamine-producing neurons, leading to motor impairments such as tremors, rigidity, and slowness of movement, alongside non-motor symptoms including fatigue, cognitive decline, and depression. With prevalence having doubled in the past 25 years, there remains a pressing need for therapies that go beyond symptomatic management to address the underlying disease process.

Bayer’s dual cell and gene therapy strategy positions it at the forefront of developing disease-modifying treatments for PD, with the potential to significantly impact patient care in the years ahead.