A novel GMP-manufactured medicinal product candidate composed of NK and γδ T cells as adjunct immunotherapy for hematopoietic stem cell transplantation.

γδ T lymphocytes and NK cells are effective to kill tumors or viral-infected cells avoiding graft versus host disease (GvHD), thus they have attracted high interest as potential tool for adoptive cell therapy. We generated an advanced therapy medicinal product (ATMP) composed of mature γδ T and NK cells to provide an innovative tool to protect patients against tumor relapse and life-threatening infection after haploidentical hematopoietic stem cell transplantation. The ATMP was manufactured and validated in a GMP facility and was obtained from leukapheresis stimulated with zoledronic acid and IL-2, afterward depleted of αβ T lymphocytes using the CliniMACS Prodigy. The ATMP is characterized by high homogeneity, cell viability, cytotoxic abilities, stability after cryogenic preservation, and it was virtually free of αβ T and B lymphocytes. Both NK and γδ T cells were activated and characterized by high expression of cytotoxic and activating receptors including NKG2D, CD16, NKp30, NKp44, and NKp46. Furthermore, γδ T lymphocytes and NK cells were cytotoxic against myeloid leukemia or neuroblastoma cells. In conclusion, we implemented a novel ATMP to be shortly translated into clinical practice, which may be used in the post-transplant phase as efficacious immunotherapy in neuroblastoma and leukemic pediatric patients.