Recent treatments of leukemias with chimeric antigen receptor (CAR) expressing T cells underline their impressive therapeutic potential. However, once adoptively transferred into patients, there is little scope left to shut them down after elimination of tumor cells or in case adverse side effects occur. This becomes of special relevance if they are directed against commonly expressed tumor associated antigens (TAAs) such as receptors of the ErbB family. To overcome this limitation, we recently established a modular CAR platform technology termed UniCAR. UniCARs are not directed against TAAs but instead against a unique peptide epitope on engineered recombinant targeting modules (TMs), which guide them to the target. In the absence of a TM UniCAR T cells are inactive. Thus an interruption of any UniCAR activity requires an elimination of unbound TM and the TM complexed with UniCAR T cells. Elimination of the latter one requires a disassembly of the UniCAR-TM complexes. Here, we describe a first nanobody (nb)-based TM directed against EGFR. The novel TM efficiently retargets UniCAR T cells to EGFR positive tumors and mediates highly efficient target-specific and target-dependent tumor cell lysis both in vitro and in vivo. After radiolabeling of the novel TM with 64Cu and 68Ga, we analyzed its biodistribution and clearance as well as the stability of the UniCAR-TM complexes. As expected unbound TM is rapidly eliminated while the elimination of the TM complexed with UniCAR T cells is delayed. Nonetheless, we show that UniCAR-TM complexes dissociate in vitro and in vivo in a concentration-dependent manner in line with the concept of a repeated stop and go retargeting of tumor cells via the UniCAR technology.
Author Info: (1) Tumor Immunology, University Cancer Center (UCC), 'Carl Gustav Carus,' TU Dresden, Dresden, Germany. (2) Helmholtz-Zentrum Dresden-Rossendorf (HZDR), Institute of Radiopharmace
Author Info: (1) Tumor Immunology, University Cancer Center (UCC), 'Carl Gustav Carus,' TU Dresden, Dresden, Germany. (2) Helmholtz-Zentrum Dresden-Rossendorf (HZDR), Institute of Radiopharmaceutical Cancer Research, Dresden, Germany. (3) Helmholtz-Zentrum Dresden-Rossendorf (HZDR), Institute of Radiopharmaceutical Cancer Research, Dresden, Germany. (4) Helmholtz-Zentrum Dresden-Rossendorf (HZDR), Institute of Radiopharmaceutical Cancer Research, Dresden, Germany. (5) Tumor Immunology, University Cancer Center (UCC), 'Carl Gustav Carus,' TU Dresden, Dresden, Germany. (6) Helmholtz-Zentrum Dresden-Rossendorf (HZDR), Institute of Radiopharmaceutical Cancer Research, Dresden, Germany. (7) Tumor Immunology, University Cancer Center (UCC), 'Carl Gustav Carus,' TU Dresden, Dresden, Germany. (8) Tumor Immunology, University Cancer Center (UCC), 'Carl Gustav Carus,' TU Dresden, Dresden, Germany. (9) Helmholtz-Zentrum Dresden-Rossendorf (HZDR), Institute of Radiopharmaceutical Cancer Research, Dresden, Germany. (10) Helmholtz-Zentrum Dresden-Rossendorf (HZDR), Institute of Radiopharmaceutical Cancer Research, Dresden, Germany. (11) Institute of Immunology, 'Carl Gustav Carus', TU Dresden, Dresden, Germany. (12) GEMoaB Monoclonals GmbH, Dresden, Germany. (13) Cellex Patient Treatment GmbH, Dresden, Germany. (14) Medical Clinic and Policlinic I, University Hospital 'Carl Gustav Carus', TU Dresden, Dresden, Germany. German Cancer Consortium (DKTK), partner site Dresden, Germany, and German Cancer Research Center (DKFZ), Heidelberg, Germany. National Center for Tumor Diseases (NCT), 'Carl Gustav Carus,' TU Dresden, Dresden, Germany. (15) Helmholtz-Zentrum Dresden-Rossendorf (HZDR), Institute of Radiopharmaceutical Cancer Research, Dresden, Germany. (16) Helmholtz-Zentrum Dresden-Rossendorf (HZDR), Institute of Radiopharmaceutical Cancer Research, Dresden, Germany. Department of Chemistry and Food Chemistry, School of Science, TU Dresden, Dresden, Germany. (17) Helmholtz-Zentrum Dresden-Rossendorf (HZDR), Institute of Radiopharmaceutical Cancer Research, Dresden, Germany. German Cancer Consortium (DKTK), partner site Dresden, Germany, and German Cancer Research Center (DKFZ), Heidelberg, Germany. National Center for Tumor Diseases (NCT), 'Carl Gustav Carus,' TU Dresden, Dresden, Germany. Department of Chemistry and Food Chemistry, School of Science, TU Dresden, Dresden, Germany. (18) Tumor Immunology, University Cancer Center (UCC), 'Carl Gustav Carus,' TU Dresden, Dresden, Germany. Helmholtz-Zentrum Dresden-Rossendorf (HZDR), Institute of Radiopharmaceutical Cancer Research, Dresden, Germany. German Cancer Consortium (DKTK), partner site Dresden, Germany, and German Cancer Research Center (DKFZ), Heidelberg, Germany. National Center for Tumor Diseases (NCT), 'Carl Gustav Carus,' TU Dresden, Dresden, Germany.
