Bispecific T-cell engagers (BiTEs) are a class of immunotherapeutics that can redirect T cells to haematological malignancies. A key advantage of BiTEs over adoptive T-cell therapies, consists of the fact that a BiTE is an “off the shelf” meaning that the same product can be given to all patients. In contrast, adoptive T-cell therapies must be made from cells taken from each patient and as a result this strategy is more time consuming and potentially more expensive. The most successful BiTE to date is blinatumomab. This agent is made up of CD3 and CD19 single-chain variable regions linked by a glycine–serine linker. It binds selectively to CD3 expressing T cells and CD19 expressing B cells, leading to the formation of immune synapses between T cells and B cells. In doing so, blinatumomab redirects unstimulated cytotoxic T cells to specifically target and lyse CD19-positive B cells. Blinatumomab is currently approved for patients with relapsed/refractory and minimal residual disease positive B-cell precursor acute lymphoblastic leukaemia (B-ALL). This review will discuss the pivotal trials with this agent and will touch upon some of the additional BiTEs that are under clinical evaluation in haematological malignancies. Finally, some remaining challenges with respect to optimising the efficacy and safety of BiTEs will be addressed.

(BELG J HEMATOL 2019;10(8):332–8)