Pilot Study of Expanded , Activated Haploidentical Natural Killer Cell Infusions for Sarcomas

Progress in the treatment of children with leukemia and lymphoma results in high cure rates but progress in the treatment of children and adolescents with solid tumors has been slow. Despite aggressive therapy with multimodality treatment involving surgery, radiation and chemotherapy, about two thirds of the patients with metastatic Ewing sarcoma (EWS), and intermediate and high risk rhabdomyosarcoma (RMS) will relapse. The available second line therapies for relapse are limited and often not effective. There is a dire need to look for treatment options beyond conventional means for the treatment of these patients. Infusions of allogeneic natural killer (NK) cells in leukemia patients have shown to be tolerated well without inducing graft versus host disease (GVHD). There is also mounting evidence that NK cells have activity against solid tumors. In the lab the investigators tested NK cell activity against cell lines from different paediatric solid tumors. Among paediatric solid tumors, EWS and RMS are exquisitely sensitive to killing by expanded NK cells; NK cells also have activity against OS cells. Preliminary clinical data suggest that donor NK cells may exert antitumor activity in children with solid tumors undergoing allogeneic hematopoietic stem cell transplantation. Taking into account the safety of adaptive NK cell infusion, and their efficacy against EWS, RMS and OS, NK cells could be a powerful new tool in the treatment of paediatric solid tumors. The great anti-tumor activity of expanded and activated NK cells, together with the feasibility of infusing haploidentical NK cells in a non-transplant setting form a compelling rationale for the clinical testing of these NK cells in patients with sarcoma.