Drug
Trastuzumab Deruxtecan
Drug Profile
| Therapeutic Class | Antibody-Drug Conjugates (ADCs) |
| Drug Class | — |
| Group | ADC |
| Mechanism of Action | HER2 targeting ADC |
| Half-life | 5.4–5.7 d (DXd payload 5.4–6.1 d) |
Study design
RT–Drug Timing Window
Study design
RT–Drug Timing Window
Radiobiological rationale for RT–drug interaction
Inconsistent radiosensitization (topo I sensitization vs. absent free-DXd effect at low dose). The key theoretical adverse event concern is the DXd class-specific ILD/pneumonitis, which overlaps radiographically and biologically with radiation pneumonitis (Cortés et al., New England Journal of Medicine, 2022; Loibl et al., New England Journal of Medicine, 2026), plus a rationale for enhanced CNS normal-tissue injury (radionecrosis) where intracranial RT fields coincide with drug exposure.
Data on this page refer exclusively to patients treated with
Trastuzumab Deruxtecan combined with SBRT, without concurrent use of
drugs from other classes.
Combination therapy data and pooled group-level evidence are available on the
ADC group page.