Immunotherapeutic options for management of relapsed or refractory B-cell acute lymphoblastic leukemia: how to select newly approved agents?

Recently, immunotherapeutic agents such as inotuzumab ozogamicin (INO), blinatumomab (BLIN), and tisagenlecleucel (TISA) have been approved for treatment of relapsed or refractory (R/R) acute lymphoblastic leukemia (ALL). No head to head trials have compared these agents. Thus, various factors influence the decision to choose an appropriate treatment for R/R ALL. INO may be preferred in patients with high tumor burden; BLIN is preferred in patients with low tumor burden or to eradicate minimal residual disease (MRD). Both INO and BLIN, compared to standard chemotherapy, increase the probability of receiving subsequent hematopoietic stem cell transplant (HSCT). TISA, approved for patients <= 25 years of age, is effective regardless of tumor burden or prior receipt of HSCT and can be used as a definite treatment in some patients. Further studies comparing the efficacy, safety, and other outcomes related to different immunotherapeutic options in combination with other treatment modalities and among themselves are needed.