TRBC2-targeting antibody-drug conjugates for the treatment of T cell cancers.

Antibody-drug conjugates (ADCs) have been remarkably successful in treating solid and hematological malignancies. Generation of ADCs for T cell cancers is challenging because the ADCs must selectively target cancerous T cells while sparing some normal T cells necessary for immune function. T cells express one of two TRBC alleles: TRBC1 or TRBC2. Normal T cells are composed of about 40% TRBC1-expressing and 60% TRBC2-expressing cells. In contrast, T cell malignancies are characterized by the clonal expression of either TRBC1 or TRBC2. Selective targeting of TRBC1 or TRBC2 enables the killing of cancer cells but preserves about 60-40% of the normal T cells. To enable such a therapy for cancers expressing TRBC2, here we developed a high-affinity anti-TRBC2 antibody. An ADC generated with this antibody and a pyrrolobenzodiazepine dimer payload showed specific killing of TRBC2+ cancers in vitro and in mouse models. The anti-TRBC2 ADC provides a promising, off-the-shelf therapy for patients with T cell cancers.