The U.S. Food and Drug Administration has approved datopotamab deruxtecan (brand name Datroway, also referred to in trial literature as Dato-DXd) for adults with unresectable or metastatic triple-negative breast cancer (TNBC) — tumors that lack estrogen receptor, progesterone receptor, and HER2 expression, and that have historically had the fewest targeted-treatment options of any major breast cancer subtype. The approval, reported in May 2026, is based on results from the international TROPION-Breast02 trial, with the U.S. arm led by researchers at Memorial Sloan Kettering Cancer Center (MSK).
What was approved
Datopotamab deruxtecan is an antibody-drug conjugate: a monoclonal antibody targeting TROP2, a protein expressed on the surface of most TNBC cells, chemically linked to a cytotoxic chemotherapy payload. The antibody carries the drug directly into TROP2-expressing tumor cells, sparing more of the surrounding healthy tissue than conventional intravenous chemotherapy. The drug is jointly developed by AstraZeneca and Daiichi Sankyo. It is not entirely new to the market — the FDA first approved it in January 2025 for a different population, HR-positive, HER2-negative metastatic breast cancer previously treated with endocrine therapy and chemotherapy, based on the related TROPION-Breast01 trial. The May 2026 action extends the drug’s label to triple-negative disease, a biologically distinct and typically more aggressive subtype.
The trial behind the approval
TROPION-Breast02 (registered as NCT05374512) is an international randomized trial comparing datopotamab deruxtecan against standard chemotherapy in patients with unresectable or metastatic TNBC. Dr. Tiffany A. Traina, MD, FASCO — Section Head of the Triple Negative Breast Cancer Clinical Research Program at MSK — led the trial’s U.S. arm and is senior author of the results, published in the Annals of Oncology in April 2026.
What the results showed
According to MSK’s reporting on the trial, patients treated with datopotamab deruxtecan had a substantially higher objective response rate than those on chemotherapy — tumor shrinkage in roughly 63% of patients, compared with about 29% on chemotherapy. Median progression-free survival was approximately 11 months on datopotamab deruxtecan, versus fewer than 6 months on chemotherapy. Median overall survival was around 24 months on the antibody-drug conjugate compared with about 18 months on chemotherapy — a roughly six-month survival benefit in a disease where treatment gains are typically measured in weeks. Reported side effects included mouth sores, gastrointestinal symptoms, and fatigue, with fewer patients discontinuing treatment because of side effects than on standard chemotherapy.
Why this matters
Triple-negative breast cancer accounts for roughly 10-15% of breast cancer diagnoses but a disproportionate share of breast cancer mortality, in part because it cannot be treated with the hormone-blocking or HER2-targeted drugs that have transformed outcomes in other subtypes, and in part because it more often recurs and spreads. Until relatively recently, cytotoxic chemotherapy was the only systemic option for most patients with metastatic TNBC. The approval of a second TROP2-directed antibody-drug conjugate class option (following earlier approvals of sacituzumab govitecan in this same disease setting) gives clinicians another targeted tool and gives patients another sequencing option once prior lines of therapy stop working. “Dato-DXd helps patients with this incredibly challenging type of breast cancer live significantly longer than they would on other treatments,” Dr. Traina said, per MSK’s reporting on the approval.
What to watch next
As with other antibody-drug conjugates, the open questions now move to sequencing and resistance: how datopotamab deruxtecan performs relative to and in combination with other TROP2- and HER2-directed conjugates already in use for breast cancer, where it fits for patients who received earlier immunotherapy or chemotherapy in the curative-intent setting, and whether biomarker testing beyond ER/PR/HER2 status can help identify which TNBC patients are most likely to benefit. For research administrators and grants professionals tracking the clinical-trials pipeline behind conjugate therapies, TROPION-Breast02 is also a useful recent example of how multi-site international registration trials (see MSK’s role as U.S.-arm lead alongside AstraZeneca and Daiichi Sankyo as trial sponsors) move from a ClinicalTrials.gov registration to an FDA label change.
Source: Memorial Sloan Kettering Cancer Center, “FDA Approves New Treatment for Triple-Negative Breast Cancer”; trial registration at ClinicalTrials.gov (NCT05374512); results published in the Annals of Oncology (April 2026).
