Abstract Ref Number = APCP30
Immunotherapy for Cancer: The Myth and the Reality
Godfrey ChiFung CHAN
Department of Paediatrics Adolescent Medicine, Queen Mary Hospital HKUShenzhen Hospital, The University of Hong Kong Stem Cells Regenerative Medicine Consortium, The University of Hong Kong
Cancer immunotherapy is not a new concept and it has been used in a wide spectrum of cancer types for a few decades. It can be classified into 4 categories including active immunotherapy, passive immunotherapy, adoptive immunotherapy and immune check point inhibitor treatment. The active immunotherapy includes cytokines therapy and tumor vaccine. For leukemia, interferon alpha for CML (before the targeted therapy era) and WT-1 peptide (WT-2725) for AML are examples of such approach. For passive immunotherapy, use of monoclonal antibody against specific tumor associated antigen is the main strategy. This includes the use of anti-CD20 (i.e. Rituximab) for ALL, anti-CD33 for AML (i.e. Mylotarg) and anti-CD30 (i.e. Brentuximab) for selected lymphomas. We witnessed both success and failure in both of the active and passive immunotherapy approaches.
They have to be used in combination with chemotherapy under most situations. For adoptive immunotherapy, it can be considered as a form of active immunotherapy but it involves the use of either autologous or allogeneic immune cells. The most common form is allogeneic hematopoietic stem cells transplant (HSCT) and it has been evolving rapidly in recent years. The availability of donor is no longer an issue with new techniques that allows us to utilize graft from haploidentical (haploid) donors (half HLA-matched donors such as parents). However, the best approach in performing haploid HSCT by either in-vivo or ex-vivo T cells depletion remains controversial and cost-effective analysis has to be included in the equation for most Asian countries. In recently years, the use of killer immunoglobulin receptor (KIR) mismatched NK cells, CD19 CAR-T cells (i.e. Kymriah) and CD19/CD3 bispecific antibody (i.e. Blinatumomab) for refractory leukemia are raising new hope. However, significant barriers remain before they can be incorporated into our routine armamentarium against leukemia.
Finally, immune check-point inhibitor (PD-1 inhibitor, i.e. Nivolumab; CTLA-4 inhibitor, i.e. Ipililumab) is an emerging concept and Nivulumab has been used in refractory Hodgkin lymphoma with good preliminary result. Whether it can be used together with other adoptive treatment remains to be explored. In summary, while era of immunotherapy appears to be coming but we have to understand their respective strengths and weaknesses so they can be applied effectively.