Table 1. Cell-surface binding and solution state properties of HER2 agonists and antagonists.
| Molecule† | Activity Type‡ | Cell-surface KD (nM) | Sites Per Cell (×10−5) | Rhyd |
| 1325 (HC118/LC205) | Agonist | 1.9+/−0.3 | 3.2+/−0.2 | 3.70+/−0.11 |
| 1321 (LC110/LC110) | Agonist | 2.5+/−0.6 | 2.8+/−0.1 | 3.66+/−0.11 |
| 1324 (LC205/LC205) | moderate antagonist | 2.0+/−0.3 | 3.8+/−0.1 | 3.80+/−0.06 |
| 1329 (HC228/HC228) | Antagonist | 1.3+/−1.3 | n.d. | 4.18+/−0.07 |
| F(ab′)2 | Antagonist | 1.2+/−0.2 | 2.8+/−0.03 | 3.95+/−0.07 |
| Trastuzumab | Antagonist | 1.6+/−0.3 | 3.0+/−0.2 | 5.15+/−0.08 |
| Fab trastuzumab | weak antagonist | 5.7+/−1.2 | 5.5+/−0.3 | 2.46+/−0.11 |
†
All molecules in this table are derived from trastuzumab. LC = light chain; HC = heavy chain. Numbers indicate the cysteine substitution position.
‡
Activity was determined by cell proliferation assays using BT474 cells.
Rhyd = hydrodynamic radius determined by size exclusion chromatography coupled-light scattering.
Standard deviation is represented by +/− values in the table.