This phase Ib/II BEGONIA study evaluated first-line datopotamab deruxtecan combined with durvalumab in unresectable locally advanced or metastatic triple-negative breast cancer. The combination demonstrated high objective response rates around 80% and durable responses, with manageable safety profiles including low rates of severe adverse events and treatment discontinuations. Efficacy was observed regardless of PD-L1 status.
Study
|
Phase Ib/II, 2-stage, open-label, platform study [BEGONIA] |
| Locally advanced or metastatic triple-negative breast cancer (TNBC) |
| Dato-DXd plus durvalumab every 3 weeks (Arm 7: PD-L1 independent, n=62; Arm 8: PD-L1 high, n=33)
|
Efficacy
|
Order: |
| cORR: 79.0% (CR 12.9%) and 81.8% (CR 6.1%) (Arm 7 and 8) |
| Median DoR: 17.6 mos vs immature |
| Median PFS: 14.0 mos [11.0-21.0] vs immature |
| Median OS: not reached vs not reached
|
Safety
|
Grade >=3 AE: increased amylase, stomatitis, rash, constipation, fatigue, vomiting, dry eye |
| Serious AE: 29.0% vs 15.2% (Arm 7 vs. 8) |
| Treatment discontinuation due to AE: 19.4% vs 9.1% |
| Immune-mediated AE any grade: 32.3% vs 33.3% |
| Oral mucositis/stomatitis Grade >=3: 16.1% vs 0 |
| Ocular surface events Grade 3: 8.1% vs 3.0% |
| Drug-related ILD/pneumonitis: 4.8% vs 3.0% (all low grade)
|
Ann Oncol. Published online 2026-05
http://doi.org/10.1016/j.annonc.2026.05.693
Reviewed by Ulas D. Bayraktar, MD on Jun 17, 2026
