Table 1.
Potency of redirected lysis by cetuximab- and panitumumab-based BiTE antibodies
| Potency of redirected lysis EC50, pg/mL |
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| Experiment no. | Effector cells | Target cells | C-BiTE | P-BiTE |
| 1 | Unstimulated CD3-selected human T cells (n = 3 donors) | Human EGFR expressing CHO cells | 55 ± 8 | 8.5 ± 3.2 |
| 2 | Unstimulated human CD3-selected T cells | SW480 human CRC cell line (KRAS-mutated) | 3.8 | 12 |
| 3 | Unstimulated human CD3-selected T cells | HCT116 Human CRC cell line (KRAS-mutated) | 14 | 17 |
| 4 | Unstimulated human CD3-selected T cells | HT29 Human CRC cell line (BRAF-mutated) | 27 | 23 |
| 5 | Stimulated Cynomolgus PBMC (n = 9 donors) | KATO III human gastric carcinoma cell line | 39 ± 44 | ND |
| 6 | Stimulated human PBMC (n = 3 Donors) | KATO III human gastric carcinoma cell line | 41 ± 45 | ND |
| 7 | Rhesus T cell line 4119 LnPx | Cynomolgus EGFR-expressing CHO cells | 20 | ND |
| 8 | Unstimulated Cynomolgus PBMC | Cynomolgus EGFR-expressing CHO cells | 570/134 | ND |
Results from various cytotoxicity assays are shown. Potency of redirected lysis is given as EC50 values for cell lysis in pg/mL Various effector and target cell combinations were tested to compare the cytotoxic potential of the C- and P- BiTE antibodies. The 51-chromium release assay (2 –4) used an E:T ratio of 10:1 and an assay duration of 18 h, the FACS-based cytotoxicity assay (1, 5–8) an E:T ratio of 10:1 and an assay period of 24 h. Experiments 2, 3 and 4 used T cells from the same human PBMC donors. ND, not determined.