Standard Parkinson’s disease treatment continues to be old drugs that get nerve cells to make dopamine, a brain chemical whose deficiency drives the central nervous system disorder. Bayer is taking a novel approach: a cell therapy that replaces dopamine production.

Bayer said the cell therapy, formerly known as BRT-DA01 and now called bemdaneprocel, met the main goal of assessing safety in its Phase 1 test. These results also showed signs the therapy led to improvement of Parkinson’s symptoms. The data were presented Monday during the International Congress of Parkinson’s Disease and Movement Disorders in Copenhagen, Denmark. Based on the safety data and early signs of clinical efficacy, Bayer said it is now preparing to advance the cell therapy to its next stage of clinical testing.

Bemdaneprocel is an “off the shelf” cell therapy derived from human embryonic stem cells. These cells are intended to replace the dopamine-producing neurons lost to Parkinson’s disease. The therapy is administered in a surgical procedure during which the cells are implanted in the patient’s brain. Bemdaneprocel was initially developed by BlueRock Therapeutics, a cell therapy biotech formed in 2016 as a joint venture between Bayer and venture capital firm Versant Ventures. Bayer acquired BlueRock in 2019, paying $240 million up front for the stake it did not already own. Another $360 million is tied to the achievement of milestones. BlueRock operates independently within the pharma giant as a wholly owned subsidiary.

Bayer says bemdaneprocel’s transplanted cells have the potential to reform neural networks and restore motor and non-motor function. The open-label Phase 1 study evaluated bemdaneprocel in 12 patients who received either a low or high dose of the experimental therapy. Patients were followed for one year, during which they received immunosuppressive drugs to prevent rejection of the transplanted cells. Patients will continue to be assessed for two years. The results presented Monday are for year one.

No serious complications associated with the treatment were reported for either of the two doses tested. There were two serious adverse effects, a seizure attributed to the surgical procedure and a case of Covid-19. Both resolved and neither was related to the cell therapy itself. The early signs of efficacy come from brain imaging scans that showed evidence the transplanted cells survived and engrafted, meaning they were accepted by the body. Secondary goals of the small study included assessing Parkinson’s symptoms. Results showed improvement according to a scale used to rate Parkinson’s symptoms and a diary tool that is used to measure the severity of the disease’s motor symptoms.

In a statement included in Bayer’s announcement of the Phase 1 data, Claire Henchcliffe, chair of the department of neurology at the University of California, Irvine, and one of the study’s principal investigators, called the early results “extremely encouraging.”

“While this is a small open-label study, meeting the study’s primary objective for safety and tolerability along with initial improvements seen in clinical outcomes represents a great step forward,” Henchcliffe said. “The hope now is that these trends continue and translate into meaningful benefit for people with Parkinson’s disease in controlled clinical trials.”

Bayer said planning is now underway for a Phase 2 clinical trial. That study is expected to begin enrolling participants in the first half of 2024.

Competition could be coming from a Parkinson’s cell therapy being developed by Aspen Neuroscience. Aspen makes this cell therapy from stem cells. But in contrast to Bayer’s allogeneic approach, the San Diego-based biotech’s therapy is made with stem cells sourced from the patient’s skin. This personalized approach is intended avoid the need for immunosuppressive drugs.  Last year, Aspen raised $147 million in financing to support ongoing preclinical development of the Parkinson’s cell therapy, called ANPD001.

Photo: Krisztian Bocsi/Bloomberg, via Getty Images