Definition

A preparation of autologous CD34+-enriched hematopoietic stem and progenitor cells (HSPCs) from mobilized peripheral blood of patients with infantile malignant osteopetrosis (IMO) that are transduced ex vivo with a lentiviral (LV) vector carrying the T-cell immune regulator 1 (TCIRG1) gene, with potential to restore TCIRG1 expression and function. Upon re-infusion of autologous CD34+-enriched HSPCs transduced with LV vector carrying TCIRG1 gene RP-L401 back into the patient, these cells express functional TCIRG1 gene. Mutations in the TCIRG1 gene, found in some patients with IMO, lead to functional impairment of the proton pump of the osteoclast.