Bispecific antibody (BsAb)

A bispecific antibody (BsAb) is an engineered protein capable of binding to two different antigens or two different epitopes on the same antigen simultaneously [1]. This dual-binding capacity allows BsAbs to perform functions that are impossible for conventional monoclonal antibodies, such as bridging immune effector cells (like T-cells) to malignant cells to induce targeted lysis [2]. In clinical practice, they are primarily utilized in oncology to treat various hematologic and solid tumors by redirecting the immune system [3]. Beyond cancer, BsAbs are used in hematology to mimic the activity of coagulation factors and in ophthalmology to inhibit multiple pro-angiogenic pathways [1, 4]. Their therapeutic use is often complicated by unique safety profiles, including systemic inflammatory responses [2].

Other names

BsAbBispecific monoclonal antibodyDual-affinity retargeting proteinDARTBispecific T-cell engagerBiTEDuoBodyCrossMAb

Bispecific antibodies function by simultaneously binding to two different epitopes or antigens, allowing for complex mechanisms such as bridging T-cells to tumor cells (T-cell engagers), co-inhibiting two signaling pathways, or mimicking the function of a missing protein complex (e.g., Factor VIII mimicry) [1, 2].