2025 American Academy of Neurology Abstract Website

Harini Sarva¹, Claire Henchcliffe², Andres Lozano³, Alfonso Fasano⁴, Suneil Kalia³, Kenny Kwok Hei Yu⁵, Cameron Brennan⁵, Nicole Floro⁶, Whitney Stemple⁶, Nauman Abid⁶, Viviane Tabar⁵
¹Department of Neurology, Weill Cornell Medicine, New York, NY, USA, ²Department of Neurology, University of California, Irvine, CA, USA, ³Division of Neurosurgery, University of Toronto, Toronto, Ontario, Canada; Krembil Brain Institute, Toronto, Ontario, Canada, ⁴Krembil Brain Institute, Toronto, Ontario, Canada; Division of Neurology, University of Toronto, Toronto, Ontario, Canada; Edmond J Safra Program in Parkinson’s Disease, Morton and Gloria Shulman Movement Disorders Clinic, Toronto Western Hospital, UHN, Toronto, Ontario, Canada, ⁵Department of Neurosurgery and Center for Stem Cell Biology, Memorial Sloan Kettering Cancer Center, New York, NY, USA, ⁶BlueRock Therapeutics LP, Cambridge, MA, USA

Objective:

To report the safety of bemdaneprocel and its impact on clinical outcomes in participants with PD through 24 months post transplantation.

Background:

Bemdaneprocel is an investigational therapy currently under development for Parkinson’s disease (PD) comprising human embryonic stem cell-derived midbrain dopaminergic neuron progenitors; preclinical studies supported proof of concept and safety. At 12 months post transplantation, predefined safety and tolerability criteria were met, and trends towards clinical benefit were observed.

Design/Methods:

In this Phase 1, open-label, 24-month, non-controlled study (exPDite, NCT04802733), 12 participants with PD received a low dose (n=5; 0.9 million cells/putamen) or high dose (n=7; 2.7 million cells/putamen) of bemdaneprocel injected using a cannula bilaterally into the postcommissural putamen during a single surgical session under general anesthesia. A 12-month immunosuppression regimen began intraoperatively.

Results:

Participants (N=12) were median 67.0 years of age, 75% male, and 67% White. Median time since PD diagnosis was 9.0 years. At 24 months post transplantation, 12 participants experienced 89 treatment-emergent adverse events (low dose, 43; high dose, 46); most were mild or moderate in severity. Three treatment-emergent serious adverse events, all unrelated to bemdaneprocel, were reported: hospitalizations due to COVID-19 (low dose), gastrointestinal hemorrhage (high dose), and a hospitalization due to seizure 1 day after surgery (high dose) considered possibly related to surgery. No deaths, discontinuations, or graft-induced dyskinesias occurred. In the high-dose cohort, MDS-UPDRS Part III OFF scores, and patient-reported ON times without troublesome dyskinesia and OFF times, indicated a continuing trend toward improved clinical assessments. Results in the low-dose cohort indicated stability or mild improvement.

Conclusions:

Bemdaneprocel demonstrated a favorable safety profile and trended toward clinical benefit or stability through 24 months post transplantation. All participants have enrolled in a continued-evaluation study (NCT05897957). These results support the ongoing development of bemdaneprocel in a Phase 3 trial to evaluate efficacy and safety in people with PD.