Bispecific Antibodies in Hematological Malignancies: A Scoping Review

SIMPLE SUMMARY: Bispecific T-cell engagers (BiTEs) and bispecific antibodies (BiAbs) have emerged as novel therapeutic modalities in the treatment of advanced hematological malignancies. BiTEs and BiAbs redirect T cells to attack tumors and facilitate T-cell-mediated cell death. Blinatumomab was the first BiTE to display proof-of-concept with its remarkable contribution towards the treatment of acute lymphoblastic leukemia. Nearly a decade later, several BiTEs/BiAbs targeting a range of tumor-associated antigens have transpired in the treatment of multiple myeloma, non-Hodgkin’s lymphoma, acute myelogenous leukemia, and acute lymphoblastic leukemia. This review summarizes the most recent evidence emerging from clinical trials regarding the use of BiAbs and BiTEs in hematological malignancies whilst highlighting the limitations of these therapeutic options and providing practical insights towards overcoming these limitations. ABSTRACT: Bispecific T-cell engagers (BiTEs) and bispecific antibodies (BiAbs) have revolutionized the treatment landscape of hematological malignancies. By directing T cells towards specific tumor antigens, BiTEs and BiAbs facilitate the T-cell-mediated lysis of neoplastic cells. The success of blinatumomab, a CD19xCD3 BiTE, in acute lymphoblastic leukemia spearheaded the expansive development of BiTEs/BiAbs in the context of hematological neoplasms. Nearly a decade later, numerous BiTEs/BiAbs targeting a range of tumor-associated antigens have transpired in the treatment of multiple myeloma, non-Hodgkin’s lymphoma, acute myelogenous leukemia, and acute lymphoblastic leukemia. However, despite their generally favorable safety profiles, particular toxicities such as infections, cytokine release syndrome, myelosuppression, and neurotoxicity after BiAb/BiTE therapy raise valid concerns. Moreover, target antigen loss and the immunosuppressive microenvironment of hematological neoplasms facilitate resistance towards BiTEs/BiAbs. This review aims to highlight the most recent evidence from clinical trials evaluating the safety and efficacy of BiAbs/BiTEs. Additionally, the review will provide mechanistic insights into the limitations of BiAbs whilst outlining practical applications and strategies to overcome these limitations.