Abstract: Pediatric Philadelphia chromosome-like (Ph-like) acute B-lymphoblastic leukemia (B-ALL), a high-risk subset of B-ALL characterized by a gene expression profile similar to that of Ph-positive ALL, has extremely poor outcome after a relapse following autologous chimeric antigen receptor (CAR)-T and haploidentical (haplo) hematopoietic stem cell transplantation(HSCT)therapy. with very limited treatment options. Donor-derived CAR T-cell therapy, the most vital advanced anticancer technology, may be a promising salvage strategy for patients with Ph-like B-ALL. Here, we presented a relapsed and refractory case of a child with Ph-like B-ALL after autologous anti-CD19 CAR T-cell therapy followed by haplo-HSCT. She successfully achieved the fourth complete remission (CR4) and maintained CR for five months after the sequential infusion of donor-derived anti-CD22 and anti-CD19 CAR T cells, with mild CRS side effects and no obvious graft-versus-host disease. A donor-derived anti-CD22 and -CD19 CAR T-cell therapy combined with a sequential infusion strategy may provide a promising alternative treatment strategy as effective and safe salvage therapy for children with recurrent and refractory Ph-like B-ALL after autologous CD19-directed CAR T-cell therapy followed by haplo-HSCT.
Keywords: Philadelphia-chromosome-like, acute lymphoblastic leukemia, chimeric antigen receptor, CD19, CD22