Table I.
Summary of Average Drug-to-Antibody Ratios (DARs) Calculated from Different Mass Spectra of T-DM1
| Sample pretreatment | Charge state | Average DARa | |||||
|---|---|---|---|---|---|---|---|
| MS conditions | Instrument | Deglycosylation | Imidazole | Lowest | Highest | From raw data | From deconvolution |
| Denaturing | Q-TOF | − | − | 43+ | 47+ | 3.3 ± 0.1 | 3.3 |
| + | − | 41+ | 48+ | 3.6 ± 0.1 | 3.5 | ||
| Native | Q-TOF | − | − | 22+ | 27+ | 3.1 ± 0.1 | 2.9 |
| − | 10 mM | 17+ | 20+ | 3.0 ± 0.1 | 3.3 | ||
| + | − | 22+ | 26+ | 3.3 ± 0.2 | 3.2 | ||
| + | 10 mM | 15+ | 19+ | 3.5 ± 0.1 | 3.3 | ||
| Q-TOF in IM-MS mode | + | − | 23+ | 25+ | 3.4 ± 0.2 | N/A | |
| Orbitrap 17.5k | − | − | 22+ | 26+ | 3.0 ± 0.2 | 3.0 | |
| − | 20 mM | 18+ | 24+ | 3.3 ± 0.2 | 3.3 | ||
| − | 40 mM | 16+ | 22+ | 2.8 ± 0.3 | 2.5 | ||
| + | − | 22+ | 26+ | 3.0 ± 0.2 | 3.1 | ||
| Orbitrap 35k | + | − | 22+ | 26+ | 3.4 ± 0.2 | 3.4 | |
| + | 20 mM | 22+ | 26+ | 3.3 ± 0.1 | 3.3 | ||
| + | 40 mM | 17+ | 25+ | 3.5 ± 0.1 | 3.4 | ||
a
Values in bold indicate DARs obtained from spectra in which all Dn species were detected.