Gene therapy is defined as a set of strategies that modify the expression of an individual’s genes or that correct abnormal genes. Each strategy involves the administration of a specific DNA (or RNA). Cell therapy is defined as the administration of live whole cells or maturation of a specific cell population in a patient for the treatment of a disease. – Bone Marrow Transplantation

Bone Marrow Transplantation for DBA Can cure the disease Widely available Graft failure Only ¼ siblings is likely to be a good Donor - Need to know mutation Good unrelated donors are rare

Gene Therapy for Immune Disorders MACROPHAGE STEM CELLS ERYTHROCYTES PLATELETS T CELLS B CELLS BASOPHILS EOSINOPHILS NEUTROPHILS COMMITTED PROGENITOR CELL

Gene Therapy for ADA Deficiency STEM CELLS ADA ADA T CELLS B CELLS COMMITTED PROGENITOR CELL ERYTHROCYTES BASOPHILS PLATELETS EOSINOPHILS NEUTROPHILS MACROPHAGE 4

Gene Therapy for ADA Deficiency MACROPHAGE STEM CELLS ERYTHROCYTES PLATELETS T CELLS B CELLS BASOPHILS EOSINOPHILS NEUTROPHILS COMMITTED PROGENITOR CELL Virus containing a normal ADA gene ADA 5

Gene Therapy for ADA Deficiency

Gene Therapy for ADA Deficiency Collect Marrow Isolate CD34+ Cells SCF MGDF FL Combine Aliquots Backup Marrow MND-ADA GCsapM-ADA Transduce x 3 Days Busulfan 75 mg/m2 ADA- Discontinue PEG-ADA Reinfuse ADA?

Gene Therapy for X-SCID: A Cautionary Tale

Gene Therapy for Hemoglobin Disorders

Gene Therapy for Hemoglobin Disorders

Why isn’t there Gene Therapy for More Diseases? Funding for vector development: $$$$$ FDA approval for Investigational New Drug: Time Institutional approval: Time RAC approval: Time Patient recruitment: Fast Vector production: $$$$

Gene Therapy for DBA Vector development is simple Procedures in place for related diseases Regulatory process is getting easier Need to develop 18-20 vectors First trials will be on adults not children Risks associated with transplant and insertion

Genome Editing: The Next Big Thing Mice Fish

Gene Editing Targeted to a single place in the genome Works well in animal models Delivery is complex – CAS9, guide and cargo Gene disruption is more common than homologous recombination Off target effects

When will we see Gene Editing in the Clinic? Improve homologous recombination frequency Efficient delivery without insertion Off target effects? Success in animal models Funding for trial development FDA approval for IND…..