Dr Geyer talks to ecancer at ESMO 2025 about data he presented from the phase 3 DESTINY-Breast05 trial comparing trastuzumab deruxtecan (T-DXd) with trastuzumab emtansine (T-DM1) in 1,635 patients with high-risk HER2-positive early breast cancer and residual invasive disease after neoadjuvant therapy.

At a median follow-up of ~30 months, T-DXd significantly improved invasive disease-free survival (IDFS) and disease-free survival (DFS) versus T-DM1 (hazard ratio 0.47 for both). Brain metastasis–free interval also favored T-DXd (HR 0.64). Grade ≥3 adverse events occurred in about half of patients in each arm, with interstitial lung disease in 9.6% (mostly grade 1–2).

Dr Geyer concludes that T-DXd demonstrated superior efficacy with manageable safety, supporting its potential as a new post-neoadjuvant standard of care.