Process development for establishing an iPSC-based therapeutic candidate for Canavan disease

Canavan disease (CD) is a genetic disease caused by autosomal recessive mutation of the aspartoacylase (ASPA) gene. Most children with infantile-onset CD, the most prevalent form of the disease, will die within the first decade of life. There is neither a cure nor a standard treatment for this disease.In this study, we developed cGMP-compatible manufacturing processes for human iPSC derivation, differentiation, and genetic modification. Using these manufacturing processes, we established iPSCs from several Canavan disease patients , coaxed them into neural progenitor cells, and introduced a functional ASPA gene into these cells through genetic modification.  Furthermore, we transplanted these genetically-modified patient iPSC-derived neural progenitor cells into the brains of a Canavan disease mouse model and demonstrated that these cells were able to rescue major phenotype of the disease. The therapeutic candidate we developed in this study has the potential to lead toward the development of a stem cell-based therapy for this disease.

The objective of the proposed research is to establish a therapeutic candidate for Canavan disease (CD), a devastating neurological disease. CD is caused by mutations of the aspartoacylase (ASPA) gene and lacks effective therapy. In the previous funding period, we have provided a proof-of-concept that the ASPA iNPCs have great therapeutic potential to ameliorate the pathological phenotypes of CD in a sustainable manner and conducted the pre-IND meeting with the FDA in 2020.

During this funding period (9/1/20 to 12/31/21), we have reached milestone 4 of the CIRM grant and addressed additional FDA comments. We have reviewed all key reagents needed for manufacturing of the ASPA iNPC cell product with quality assurance, established materials and procedures for PBMC isolation from blood samples and tested the ability of these PBMCs to be reprogrammed into iPSCs (note: we changed starting materials from skin to blood based on advice from the CIRM TAP meeting), determined transduction efficiency of the LV-EF1α-hASPA lentiviral transduction in ASPA iNPCs, submitted informal letter to the FDA to explain delivery device and delivery site in the brain and obtained the FDA approval, and tested the ASPA iNPC purity by flow cytometry to identify cells that comprise the minority of the cell product. We have also addressed additional FDA comments from the pre-IND meeting to prepare for IND-enabling studies and the IND meeting.