Hematopoietic stem cell transplantation in the era of molecular targeted therapy

Recent developments in the field of molecular targeted therapy are certainly remarkable. However, the role of hematopoietic stem cell transplantation (HSCT) cannot be the same in this trend of targeted therapy. In the past, HSCT was the sole and ultimate treatment for refractory hematological malignancies, mainly because the conditioning regimens were strong and administering any additional therapy was impossible. In recent years, the conditioning regimens have become less intensive, thus enabling the use of additional therapies post-transplantation. In this review, we have discussed the use of each targeted therapy, such as TKIs for Philadelphia chromosome positive disease, Flt3 inhibitors, checkpoint inhibitors, monoclonal antibodies, and hypomethylating agents, in the context of using them with HSCT. Furthermore, we have discussed the importance of the intensity of chemotherapy and conditioning for HSCT and whether the depth of remission and the time of achieving deep remission are important. MRD tests can help to further delineate this point. Molecular targeted therapy will be more prevalent in the near future in the treatment of hematological malignancies where each new agent may impact the GVHD/GVL effect. Thus, clinical trials in the next decade will mostly focus on the role of HSCT and on the methods of combining it with targeted agents to provide the best therapeutic option to patients.