Our Approach: Using Tissue-derived “Adult” Stem Cells

Homologous Cells

Our therapeutic premise is to use tissue-derived stem cells only in that same organ, i.e., a homologous approach. For example, to use CNS-derived neural stem cells for the treatment of CNS disorders and liver-derived cells for the treatment of liver disorders. These multipotent, tissue-derived “adult” stem cells are naturally pre-programmed to become the mature functional cells of the organ in which they are found, so they are directly transplantable into the same type of organ. Conversely, embryonic stem (ES) and induced pluripotent stem (iPS) cells have the potential to differentiate into any of the various cell types of the body, and so they would need to be re-programmed or genetically modified in order to reduce the risk of transplanting unwanted cell types.

Allogeneic Transplantation

Cells, tissues or organs for transplantation may be either allogeneic (donor-derived) or autologous (derived from the patient). Our neural stem cells derived from healthy donors are ready for use without modification, while those derived from patients may first need to be genetically modified or corrected to eliminate the inherent disease or disorder. We therefore posit allogeneic transplantation of naturally healthy cells to be the more feasible approach.

Scalable and Bankable “Stem Cells in a Bottle”

Cryopreserved lines of donor-derived cells can be reproduced at commercial scale as “stem cells in a bottle,” then distributed for patient doses as needed, much like an off-the-shelf pharmaceutical product. Stem cells derived directly from the patient that require a costly personalized implementation and one-off safety protocol to be modified, grown and expanded on an ad hoc basis, may not be practicable for timely therapeutic intervention.

Validating Our Approach

Preclinical proof-of-concept: Extensive preclinical data shows that our human neural stem cells engraft, migrate and differentiate appropriately after transplantation into cells of the various components of the central nervous system (CNS): the brain, the spinal cord and the eye.

Safety and tolerability: Our Phase 1 trial in neuronal ceroid lipofuscinosis (NCL, also referred to as Batten disease), initiated in 2006, was the first ever FDA-authorized clinical trial of human neural stem cells. Data from this landmark trial, reported in June 2009, demonstrated the clinical safety and tolerability of the cells, and included evidence of engraftment and long-term survival of the donor cells. We continue to follow patients who completed this trial, some of whom are now more than three years post-transplant.

Long-term survival: We also have data gathered from our Phase 1 trial in NCL, which provides evidence that our HuCNS-SC^® cells survive and migrate following transplantation. Importantly, our clinical data also indicates that our HuCNS-SC cells can persist long-term after immunosuppression treatment is discontinued. Other donor-derived tissue and organ transplants typically require life-long immunosuppression, which carries increased risk for cancer and opportunistic infections. This clinical data supports our belief that the central nervous system is "immune-privileged" and that a relatively brief period of immunosuppression may be all that is required to avoid the risk of transplant rejection within the CNS.

Production readiness: We have manufactured our HuCNS-SC^® product candidate for clinical trials since 2006. Our highly purified, HuCNS-SC human neural stem cells, produced according to current Good Manufacturing Practices (cGMP) in a US Food and Drug Administration (FDA) registered facility, are not modified in any way. This minimizes the risk of transplanting unwanted cell types, or cells that may turn into unwanted cell types, thereby presenting fewer scientific, technical and regulatory challenges than either embryonic stem (ES) or induced pluripotent stem (iPS) cells.

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