Study Rationale: We have shown that although cell transplants are able to produce dopamine and improve motor problems in some individuals with Parkinson’s disease (PD), differences in the quality of cells or the mutation profile of the recipient may have caused the transplants to fail in others. To address these issues, we will use a reliable source of dopamine progenitor cells (DAPC-1) and focus on subjects whose PD is due to mutations in Parkin, a population with a less complex disease profile than that of idiopathic PD. This study will particularly beneficial because these individuals are often excluded from other trials.
Hypothesis: We hypothesize that transplantation of DAPC-1 in subjects with Parkin mutations will be safe and will restore their motor function.
Study Design: After obtaining approval for the trial, we will transplant individuals with either of two doses of DAPC-1 cells (with each dose to be tested on four subjects). Subjects will be then assessed to determine whether any adverse events occur and whether their motor function shows improvement between 1 and 12 or 18 months after surgery (depending on whether they elect to be grafted on the contralateral side).
Impact on Diagnosis/Treatment of Parkinson’s Disease: Confirming the safety and efficacy of DAPC-1 transplantation in Parkin-linked PD will pave the way to explore this therapeutic approach for non-genetic forms of PD. This trial will provide criteria to better define the type of idiopathic individuals to be enrolled in future cell-replacement trials.
Next Steps for Development: By testing two doses, we can better assess efficacy and more systematically explore the potential of cell-based therapies in future genetic and non-genetic cohorts. We expect to advance towards Phase 2 trials within a few years (a process that could be accelerated if our discussions with the FDA are successful).