Safety, Tolerability, and Clinical Assessment of Bemdaneprocel for Parkinson’s Disease: Results up to 18 Months From a Phase 1 Study

Background and Objective

People with Parkinson’s disease experience reduced health-related quality of life that persists despite standard treatment.¹

• Current standard treatments for Parkinson’s disease motor symptoms do not address the loss of dopaminergic neurons.²
• Bemdaneprocel is an investigational therapy comprising dopaminergic neuronal progenitors derived from human embryonic stem cells.^3,4
• exPDite is a Phase 1 multicenter, multisite, open-label, nonrandomized study (NCT04802733).

Objective: To evaluate the safety of bemdaneprocel and its impact on motor outcomes up to 18 months post transplantation, 6 months post discontinuation of immunosuppression, in participants with Parkinson’s disease.

Trial Design and Endpoints

• Participants with Parkinson’s disease with motor symptoms inadequately controlled by standard treatments were >=50 to <=78 years of age in Canada, or >=60 to <=78 in the US.
• A total of 12 participants enrolled sequentially^c.
• 18F-DOPA PET was performed at baseline, 12, and 18 months post transplantation, and will be performed at 24 months post transplantation.
• MRI was performed at screening, intraoperatively, postoperatively, and 1, 3, 6, 12, and 18 months post transplantation, and will be performed at 24 months post transplantation.
• Primary: Assess safety and tolerability of bemdaneprocel at 1 year post transplantation.
• Secondary: Assess evidence of survival of transplanted cells and motor effects at 1 and 2 years post transplantation.

Safety and Tolerability

No deaths, discontinuations, or graft-induced dyskinesias occurred.

• All participants reported >=1 TEAE, but most were mild or moderate in severity.
• 3 TESAEs occurred; none were related to bemdaneprocel.
• Feasibility of stereotactic administration was demonstrated: all participants received the intended number of cell deposits.

Conclusions

Exploratory outcomes were stable or improved through 18 months, 6 months post discontinuation of immunosuppression.

• No serious adverse events were attributed to the transplanted cells or immunosuppression.
• No graft-induced dyskinesias were reported throughout the 18 months.
• All participants will be asked to enroll in a long-term extension study for continued evaluation of safety and efficacy.
• Participants in the high-dose cohort trended more strongly toward improvement compared with participants in the low-dose cohort.
• These findings should be interpreted carefully given the small, open-label nature of this study.

These findings support the continued development of bemdaneprocel for the treatment of people with Parkinson’s disease.

Bemdaneprocel was well tolerated, with no major safety issues in all 12 participants through 18 months.