29844189 , Related PDB id: 6BA5
- Qi J, Li X, Peng H, Cook EM, Dadashian EL, Wiestner A, Park H, Rader C
- Potent and selective antitumor activity of a T cell-engaging bispecific antibody targeting a membrane-proximal epitope of ROR1.
- Proc Natl Acad Sci U S A. 2018 Jun 12;115(24):E5467-E5476. doi:, 10.1073/pnas.1719905115. Epub 2018 May 29.
- T cell-engaging bispecific antibodies (biAbs) present a promising strategy for cancer immunotherapy, and numerous bispecific formats have been developed for retargeting cytolytic T cells toward tumor cells. To explore the therapeutic utility of T cell-engaging biAbs targeting the receptor tyrosine kinase ROR1, which is expressed by tumor cells of various hematologic and solid malignancies, we used a bispecific ROR1 x CD3 scFv-Fc format based on a heterodimeric and aglycosylated Fc domain designed for extended circulatory t1/2 and diminished systemic T cell activation. A diverse panel of ROR1-targeting scFv derived from immune and naive rabbit antibody repertoires was compared in this bispecific format for target-dependent T cell recruitment and activation. An ROR1-targeting scFv with a membrane-proximal epitope, R11, revealed potent and selective antitumor activity in vitro, in vivo, and ex vivo and emerged as a prime candidate for further preclinical and clinical studies. To elucidate the precise location and engagement of this membrane-proximal epitope, which is conserved between human and mouse ROR1, the 3D structure of scFv R11 in complex with the kringle domain of ROR1 was determined by X-ray crystallography at 1.6-A resolution.