The redirection of T cells against tumors holds much promise for the treatment of cancer. Two main approaches for T-cell redirection involve their genetic modification with chimeric antigen receptors (CAR), or the use of recombinant proteins designated bispecific T-cell engagers (BiTE). These approaches have demonstrated dramatic effects in patients with hematologic cancers, although limited effect against solid cancers. Here, we review and compare the successes and challenges of these two types of immunotherapies, with special focus on their mechanisms, and discuss strategies to improve their efficacy against cancer.

Significance: CAR and BiTE cancer therapies have generated much excitement, but although the therapies are potentially competitive, information directly comparing the two is difficult to obtain. Here, we present the fundamentals of each approach and compare the range and level of functions they can elicit from T cells, and their efficacy against cancers. Cancer Discov; 8(8); 924–34. ©2018 AACR.