Sarah Tettamanti

Targeting of acute myeloid leukaemia by cytokine-induced killer cells redirected with a novel CD123-specific chimeric antigen receptor

Current therapeutic regimens for acute myeloid leukaemia (AML) are still associated with high rates of relapse. Immunotherapy with T‐cells genetically modified to express chimeric antigen receptors (CARs) represents an innovative approach. Here we investigated the targeting of the interleukin three receptor alpha (IL3RA; CD123) molecule, which is overexpressed on AML bulk population, CD34+ leukaemia progenitors, and leukaemia stem cells (LSC) compared to normal haematopoietic stem/progenitor cells (HSPCs), and whose overexpression is associated with poor prognosis. Cytokine‐induced killer (CIK) cells were transduced with SFG‐retroviral‐vector encoding an anti‐CD123 CAR. Transduced cells were able to strongly kill CD123+ cell lines, as well as primary AML blasts. Interestingly, secondary colony experiments demonstrated that anti‐CD123.CAR preserved in vitro HSPCs, in contrast to a previously generated anti‐CD33.CAR, while keeping an identical cytotoxicity profile towards AML. Furthermore, limited killing of normal monocytes and CD123‐low‐expressing endothelial cells was noted, thus indicating a low toxicity profile of the anti‐CD123.CAR. Taken together, our results indicate that CD123‐specific CARs strongly enhance anti‐AML CIK functions, while sparing HSPCs and normal low‐expressing antigen cells, paving the way to develop novel immunotherapy approaches for AML treatment.

Acute myeloid leukemia and novel biological treatments: Monoclonal antibodies and cell-based gene-modified immune effectors

In the context of acute myeloid leukemia (AML) treatment, the interface between chemotherapy and immunotherapy is at present getting closer as never before. Scientific research is oriented in overcoming the main limits of actual chemotherapeutic regimens against AML, which still accounts for a considerable number of relapsed or resistant forms. A lot of investments have been done in the use of monoclonal antibodies (mAbs) and recently gene-modified immune cells have been considered as an alternative approach whenever chemotherapy fails to eradicate the disease. In this sense, AML is a potential suitable target for immunotherapeutic approaches, due to overexpression of several tumor antigens. Here we describe the state of the art of mAbs and cellular therapies employing engineered immune effectors, developed against specific AML antigens, in a window embracing preclinical research and translational studies to the clinical setting.

CD123 AML targeting by chimeric antigen receptors: A novel magic bullet for AML therapeutics?

Chimeric antigen receptor (CAR) modified T cells have emerged as powerful tools for controlling leukemias. We recently showed that anti-CD123 CAR-expressing cytokine-induced killer T cell treatment is an effective immunotherapeutic approach to eradicate Acute Myeloid Leukemia (AML) cells. Here, we discuss how this genetically modified cell-based strategy could be relevant to the field of AML therapeutics.

Advanced Targeted, Cell and Gene-Therapy Approaches for Pediatric Hematological Malignancies: Results and Future Perspectives

Despite the survival of pediatric patients affected by hematological malignancies being improved in the last 20 years by chemotherapy and hematopoietic stem cell transplantation, a significant amount of patients still relapses. Treatment intensification is limited by toxic side effects and is constrained by the plateau of efficacy, while the pipeline of new chemotherapeutic drugs is running short. Therefore, novel therapeutic strategies are essential and researchers around the world are testing in clinical trials immune and gene-therapy approaches as second-line treatments. The aim of this review is to give a glance at these novel promising strategies of advanced medicine in the field of pediatric leukemias. Results from clinical protocols using new targeted “smart” drugs, immunotherapy, and gene therapy are summarized, and important considerations regarding the combination of these novel approaches with standard treatments to promote safe and long-term cure are discussed.

Preclinical Efficacy and Safety of CD19CAR Cytokine-Induced Killer Cells Transfected with Sleeping Beauty Transposon for the Treatment of Acute Lymphoblastic Leukemia

Infusion of patient-derived CD19-specific chimeric antigen receptor (CAR) T cells engineered by viral vectors achieved complete remission and durable response in relapsed and refractory (r/r) B-lineage neoplasms. Here, we expand on those findings by providing a preclinical evaluation of allogeneic non-viral cytokine-induced killer (CIK) cells transfected with the Sleeping Beauty (SB) transposon CD19CAR (CARCIK-CD19). Specifically, thanks to a large-scale 18-day manufacturing process, it was possible to achieve stable CD19CAR expression (62.425 ± 6.399%) and efficient T-cell expansion (23.36 ± 3.00-fold). Frozen/thawed CARCIK-CD19 remained fully functional both in vitro and in an established patient-derived xenograft (PDX) of MLL-ENL rearranged acute lymphoblastic leukemia (ALL). CARCIK-CD19 showed a dose-dependent antitumor response and prolonged persistence in a PDX, bearing the feature of a Philadelphia-like ALL with PAX5/AUTS2 translocation, and in a survival model of lymphoma, achieving complete eradication of disseminated tumors. Finally, the infusion of CARCIK-CD19 proved to be safe and well tolerated in a biodistribution and toxicity model. The infused cells persisted in the hematopoietic and post-injection perfused organs until the end of the study and consisted of CD8+, CD56+, and CAR+ T cells. Overall, these findings provide important implications for non-viral technology and the proof-of-concept that donor-derived CARCIK-CD19 are indeed effective against relapsed ALL, a possibility that will be tested in Phase I/II clinical trials after allogeneic hematopoietic stem-cell transplantation.