SUMMARY: The FDA on May 22, 2026, approved DATROWAY® (Datopotamab Deruxtecan-dlnk) for adult patients with unresectable or metastatic Triple-Negative Breast Cancer (TNBC) who are not candidates for PD-1/PD-L1 inhibitor therapy.
Breast cancer is the most common cancer among women in the US and about 1 in 8 women (12%) will develop invasive breast cancer during their lifetime. It is estimated that in the US, approximately 321,910 new cases of female breast cancer will be diagnosed in 2026, and about 42,140 women will die of the disease, largely due to metastatic recurrence.
Triple-Negative Breast Cancer (TNBC) which accounts for roughly 10-15% of breast cancers remains one of the most biologically aggressive breast cancer subtypes, defined by the absence of estrogen and progesterone receptor expression and lack of HER2 overexpression. The disease is associated with aggressive clinical behavior, high rates of visceral and CNS metastases, early recurrence, and limited Overall Survival once metastatic. Despite therapeutic advances, metastatic TNBC carries a dismal prognosis, with 5-year relative survival rates near 15%. While immune checkpoint inhibitors and targeted therapies have improved prognosis in selected populations, nearly 70% of patients with metastatic TNBC are not candidates for immunotherapy and continue to rely on conventional chemotherapy as first-line treatment. For these individuals, response rates remain modest, disease control is often short-lived, and many patients never reach subsequent lines of therapy. Consequently, there is a critical need for therapies capable of improving outcomes earlier in the disease course.
A Potential New Standard for Patients Ineligible for Immunotherapy
Datopotamab-deruxtecan (Dato-DXd) is an ADC composed of a TROP2-directed monoclonal antibody conjugated to a potent topoisomerase I inhibitor via a stable tetrapeptide-based cleavable linker. Trop-2 is a transmembrane calcium signal transducer that stimulates cancer cell growth. TROP-2 is overexpressed in several epithelial cancers including cancers of the breast, colon and lung, and has limited expression in normal human tissues. It has been associated with poor Overall and Disease-Free Survival in several types of solid tumors. TROP-2 is expressed in more than 85% of breast tumors including Triple Negative Breast Cancer. Upon binding to TROP-2, the anti-TROP-2 monoclonal antibody is internalized and delivers the payload directly into the tumor cell, making it a suitable transporter for the delivery of cytotoxic drugs. Further, the cleavable linker enables the payload to be released both intracellularly into the tumor cells, as well as the tumor microenvironment, thereby allowing for the delivery of therapeutic concentrations of the active drug in bystander cells to which the conjugate has not bound. The agent has already demonstrated efficacy in Hormone Receptor-positive, HER2-negative metastatic breast cancer and previously showed encouraging activity in heavily pretreated TNBC populations.
Results from the Phase III TROPION-Breast02 trial suggest that Datopotamab Deruxtecan (Dato-DXd) may offer a meaningful new treatment option for this underserved population.
Trial Design and Patient Population
TROPION-Breast02 was a global, randomized, open-label Phase III study evaluating Dato-DXd versus investigator’s choice chemotherapy in patients with previously untreated, locally recurrent inoperable or metastatic TNBC, who were not eligible for immunotherapy.
Between May 2022 and June 2024, 644 patients were enrolled and randomized in a 1:1 ratio to receive either Dato-DXd 6 mg/kg IV every three weeks (N=323) or standard chemotherapy (N=321). The study’s dual Primary endpoints were Progression-Free Survival (PFS) assessed by Blinded Independent Central Review and Overall Survival (OS). Importantly, the trial population reflected real-world clinical practice, including patients with early relapse following curative-intent therapy, short disease-free intervals, and brain metastases, groups frequently underrepresented in pivotal studies.
Significant Improvements in Progression-Free and Overall Survival
The study met both of its Primary endpoints, demonstrating statistically significant and clinically meaningful improvements in PFS and OS with Dato-DXd compared with chemotherapy.
Median PFS reached 10.8 months with Dato-DXd versus 5.6 months with chemotherapy, translating to a 43% reduction in the risk of disease progression or death (HR 0.57; P < 0.0001).
Overall Survival findings were equally compelling. Patients receiving Dato-DXd achieved a median OS of 23.7 months compared with 18.7 months for those treated with chemotherapy, representing an approximately five-month survival benefit (HR 0.79; P =0.029).
Beyond survival outcomes, Dato-DXd also demonstrated superior antitumor activity. Confirmed Objective Response Rates were higher and was 64% and 30% in the respective arms. Responses were more durable, with a longer median duration of response.
Investigators noted that efficacy benefits were generally consistent across key patient subgroups, including PD-L1 status, disease-free interval, and geographic region. Although certain regional analyses showed variability in OS hazard ratios, these findings were exploratory and likely influenced by baseline prognostic imbalances and differential use of subsequent ADC therapies.
Expanding the Role of TROP2-Directed ADCs
The positive findings from TROPION-Breast02 further strengthen the emerging role of TROP2-targeted ADCs in metastatic TNBC. The results complement observations from the Phase III ASCENT-03 study evaluating Sacituzumab govitecan in a similar first-line setting. Together, these studies provide growing evidence that TROP2-directed ADCs can outperform standard chemotherapy and potentially redefine treatment paradigms for patients with advanced TNBC.
However, important differences exist between the trials, including eligibility criteria, disease-free interval requirements, chemotherapy comparators, and access to subsequent therapies. Notably, TROPION-Breast02 enrolled patients regardless of disease-free interval, allowing inclusion of patients with particularly aggressive disease who are often excluded from clinical trials.
Manageable Safety Profile Supports Long-Term Treatment
Safety findings were consistent with the established profile of Dato-DXd and did not reveal any new safety signals. Grade 3 or higher treatment-related adverse events occurred in 33% of patients receiving Dato-DXd and 29% of those receiving chemotherapy. Importantly, treatment discontinuation due to adverse events was less frequent with Dato-DXd (4%) than with chemotherapy (7%). No treatment-related deaths were reported in either treatment arm.
The most commonly observed adverse events included stomatitis, nausea, gastrointestinal toxicities, and ocular surface events such as dry eye. Most oral and ocular toxicities were low grade and manageable with supportive care measures. Notably, no patients discontinued Dato-DXd because of stomatitis, while only a small proportion discontinued treatment due to ocular events. When treatment exposure was taken into account, overall adverse event rates, including serious toxicities and treatment discontinuations, were lower with Dato-DXd than with chemotherapy, highlighting the tolerability of prolonged treatment.
Patient-Reported Outcomes Reinforce Clinical Benefit
Beyond traditional efficacy endpoints, Patient-Reported Outcomes (PROs) provided additional evidence supporting the clinical value of Dato-DXd.
Compared with chemotherapy, patients receiving Dato-DXd experienced delayed deterioration in pain, physical functioning, breast and arm symptoms, and overall Quality of Life measures. These findings suggest that the survival improvements achieved with Dato-DXd were accompanied by meaningful preservation of day-to-day functioning and patient well-being.
Looking Ahead
Although the open-label design represents a limitation, the overall results from TROPION-Breast02 are highly encouraging. The study demonstrated robust improvements in both Progression-Free and Overall Survival while maintaining a manageable safety profile in a patient population with historically limited treatment options.
As the treatment landscape for TNBC continues to evolve, these findings position Dato-DXd as a strong candidate for first-line therapy in patients with locally recurrent inoperable or metastatic TNBC who are not eligible for immunotherapy.
For oncology clinicians, the trial marks a significant step forward in addressing one of the most challenging segments of breast cancer care and underscores the growing impact of Antibody-Drug Conjugates in transforming outcomes for patients with aggressive disease.
Datopotamab deruxtecan in patients with untreated, advanced triple-negative breast cancer (TROPION-Breast02): a randomised, open-label, international, phase III trial. Dent R, Shao Z, Schmid P, on behalf of the TROPION-Breast02 investigators. Annals of Oncology, April 03, 2026. https://doi.org/10.1016/j.annonc.2026.03.008.
