Acute lymphoblastic leukemia (ALL) accounts for approximately 20% of all acute leukemia seen in adults, and is the single most common cancer diagnosed during childhood. Cure rates have improved significantly for children who receive intensive chemotherapy, but the prognosis for adults remains poor. Allogeneic hematopoietic stem cell transplantation (HCT) is the salvage treatment of choice for children with relapsed ALL who have appropriate donors and is increasingly being used to treat adults in first remission. Advances in donor selection and supportive care have improved the outcome for patients with ALL undergoing allogeneic HCT, and leukemia relapse or complications related to graft-versus-host disease (GVHD) have emerged as the most common causes of treatment failure. In principle, targeting malignant cells by adoptive T cell therapy could provide an approach to therapy that would have negligible toxicity to normal cells. This project seeks to promote the immunologic clearance of leukemic cells after HCT without aggravating GVHD by the adoptive transfer of T cells that are engineered to express a chimeric antigen receptor (CAR) specific for the CD19 molecule on ALL stem and progenitor cells. Recent collaborative work by the Co- Principal Investigators in a nonhuman primate model has demonstrated that virus-specific T cells derived from the central memory (TCM) subset of cells have the ability to persist long-term in vivo and establish a reservoir of functional T cell memory. In preliminary work, we have developed reagents necessary to arm human central memory T cells specific for cytomegalovirus (CMV) pp65 with a CD19- specific CAR. In this project, we will optimize the cell processing methods for clinical application and conduct a clinical trial in which """"""""bi-specific"""""""" T-cells will be adoptively transferred following HCT to promote an antileukemic effect.
The specific aims are:
Aim 1. To determine the safety and anti-tumor activity of adoptive therapy with donor TCM-derived bi-specific (CMVpp65xCD19) CD8+ TE clones for patients with CD19+ ALL following HLA matched allogeneic HCT.
Aim 2. To evaluate novel CD19-specific CAR vectors that encode a marker for rapid selection of transduced T cells and a costimulatory domain in tandem with the CD36 chain.
The majority of adults and a significant fraction of children that develop acute lymphoblastic leukemia (ALL) will die of progressive disease. The studies in this application will evaluate adoptive T cell therapy for ALL as an adjunct to hematopoietic stem cell transplantation using T cells that have an innate capacity to persist in vivo and are engineered to recognize a molecule expressed on the earliest leukemia progenitors. If this therapy safely eliminates residual ALL, this will improve the outcome of hematopoietic stem cell transplantation and provide opportunities to reduce the intensity of the preparative regimen and employ this therapy in the non-transplant setting.
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