On October 19, 2025 Astrazeneca and Daiichi Sankyo reported positive results from the TROPION-Breast02 Phase III trial showed Datroway (datopotamab deruxtecan) demonstrated a statistically significant and clinically meaningful improvement for the dual primary endpoints of overall survival (OS) and progression-free survival (PFS) compared to investigator’s choice of chemotherapy as 1st-line treatment for patients with locally recurrent inoperable or metastatic triple-negative breast cancer (TNBC) for whom immunotherapy was not an option.
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These late-breaking results will be presented today during a Proffered Paper session at the 2025 European Society for Medical Oncology (ESMO) (Free ESMO Whitepaper) Congress in Berlin, Germany (abstract #LBA21).
Datroway demonstrated a 5.0-month improvement in median OS compared to chemotherapy (hazard ratio [HR] 0.79; 95% confidence interval [CI] 0.64-0.98; p=0.0291). Median OS was 23.7 months for patients treated with Datroway versus 18.7 months for those treated with chemotherapy.
Datroway reduced the risk of disease progression or death by 43% compared to chemotherapy (HR 0.57; 95% CI 0.47-0.69; p<0.0001) as assessed by blinded independent central review (BICR). Median PFS was 10.8 months for patients treated with Datroway versus 5.6 months for those treated with chemotherapy.
In addition to patients whose tumours did not express PD-L1, TROPION-Breast02 enrolled patients with PD-L1 expressing tumours for whom immunotherapy was not an option due to other factors.
Rebecca Dent, MD, FRCP, Professor and Deputy Chief Executive Officer, National Cancer Centre Singapore, and principal investigator for the trial, said: "In TROPION-Breast02, datopotamab deruxtecan meaningfully extended patients’ lives and nearly doubled their time without disease progression. These are significant outcomes for patients with metastatic triple-negative breast cancer who are not suitable candidates for immunotherapy, and remarkable results considering the trial included a subset of patients with highly aggressive disease who are often excluded from research in this setting."
Susan Galbraith, Executive Vice President, Oncology Haematology R&D, AstraZeneca, said: "The TROPION-Breast02 results show for the first time that these triple-negative breast cancer patients may have an alternative to chemotherapy in the 1st-line setting that can both delay the progression of their disease and prolong their lives. For Datroway to have so significantly improved patient outcomes in the 1st-line metastatic setting as monotherapy also gives us great confidence in its potential in combination with Imfinzi, and in the early-stage, potentially curative setting where our next studies are ongoing."
Ken Takeshita, Global Head, R&D, Daiichi Sankyo, said: "Patients with metastatic triple-negative breast cancer have one of the worst prognoses of any breast cancer subtype, and for those who are not candidates for immunotherapy, chemotherapy has long been the 1st-line standard of care. The TROPION-Breast02 results show Datroway has the potential to replace traditional chemotherapy in this setting and to meaningfully improve survival of patients."
Datroway is a specifically engineered TROP2-directed DXd antibody drug conjugate (ADC) discovered by Daiichi Sankyo and being jointly developed and commercialised by AstraZeneca and Daiichi Sankyo.
Summary of efficacy results
Datroway (n=323)
ICC (n=321)
Median OS, months (95% CI)
23.7 (19.8-25.6)
18.7 (16.0-21.8)
HR (95% CI)
0.79 (0.64-0.98)
p-value
0.0291
Median PFS by BICR, months (95% CI)
10.8 (8.6-13.0)
5.6 (5.0-7.0)
HR (95% CI)
0.57 (0.47-0.69)
p-value
<0.0001
Median PFS by investigator, months (95% CI)
9.6 (7.4-11.2)
5.2 (4.2-5.6)
HR (95% CI)
0.56 (0.47-0.67)
Confirmed ORR, %
62.5
29.3
CR, % (n)
9.0 (29)
2.5 (8)
PR, % (n)
53.6 (173)
26.8 (86)
Median DoR, months (95% CI)
12.3 (9.1-15.9)
7.1 (5.6-8.9)
As of 25 August 2025, data cut-off, 45 patients (14%) remained on Datroway and 8 patients (3%) on chemotherapy.
BICR, blinded independent central review; CI, confidence interval; CR, complete response; DoR, duration of response; HR, hazard ratio; ICC, investigator’s choice of chemotherapy; ORR, objective response rate; OS, overall survival; PFS, progression-free survival; PR, partial response
Patients receiving Datroway were on treatment more than twice as long as those receiving chemotherapy (median duration of treatment of 8.5 versus 4.1 months) and experienced a lower rate of treatment-related adverse events (TRAEs) associated with discontinuation (4% versus 7%). Grade 3 or higher TRAEs occurred in 33% and 29% of patients in the Datroway and chemotherapy arms, respectively. The most common Grade 3 or higher TRAEs were neutropenia (3%, 13%), stomatitis (8%, 0%), leukopenia (<1%, 4%), fatigue (3%, 3%), vomiting (1%, <1%), anaemia (2%, 3%), alopecia (0%, <1%), peripheral neuropathy (0%, 2%), dry eye (1%, 0%), nausea (<1%, <1%), decreased appetite (<1%, <1%) and constipation (<1%, 0%). There was one Grade 5 interstitial lung disease (ILD) event in the Datroway arm adjudicated as drug-related by an independent committee. This event was characterised as Grade 3 pneumonitis and cause of death was attributed to disease progression by the treating investigator.
AstraZeneca and Daiichi Sankyo will also present updated results from the BEGONIA Phase Ib/II trial at ESMO (Free ESMO Whitepaper) showing Datroway in combination with Imfinzi (durvalumab) continued to demonstrate robust anti-tumour activity as 1st-line treatment for patients with metastatic TNBC across PD-L1 expression levels and specifically in those with high PD-L1-expressing tumours. These results will be presented on Monday, 20 October (abstract #555MO).
AstraZeneca and Daiichi Sankyo are evaluating Datroway across stages and treatment settings of TNBC in three additional Phase III trials. TROPION-Breast03 is evaluating Datroway with or without Imfinzi in patients with Stage I-III TNBC with residual invasive disease after neoadjuvant systemic therapy. TROPION-Breast04 is evaluating neoadjuvant Datroway plus Imfinzi in patients with Stage II-III triple-negative or hormone receptor (HR)-low, HER2-low or -negative breast cancer. TROPION-Breast05 is evaluating 1st-line Datroway with or without Imfinzi in patients with metastatic TNBC whose tumours express PD-L1.
Notes
Triple-negative breast cancer
TNBC accounts for approximately 15% of all breast cancer cases, with an estimated 345,000 diagnoses globally each year.1,2 TNBC is diagnosed more frequently in younger and premenopausal women, and is more prevalent in Black and Hispanic women.3-5 Metastatic TNBC is the most aggressive type of breast cancer and has one of the worst prognoses, with median OS of just 12 to 18 months and only about 14% of patients living five years following diagnosis.3,6,7
While some breast cancers may test positive for oestrogen receptors, progesterone receptors or overexpression of HER2, TNBC tests negative for all three.3 Due to its aggressive nature and absence of common breast cancer receptors, TNBC is characteristically difficult to treat.3 For patients with metastatic disease with PD-L1 expressing tumours, the addition of immunotherapy to chemotherapy has improved outcomes in the 1st-line setting.8,9 However, for the approximately 70% of patients with metastatic TNBC who are not candidates for immunotherapy, chemotherapy remains the 1st-line standard of care.10,11
TROP2 is a protein broadly expressed in several solid tumours including TNBC.12 TROP2 is associated with increased tumour progression and poor survival in patients with breast cancer.13,14
TROPION-Breast02
TROPION-Breast02 is a global, multicentre, randomised, open-label Phase III trial evaluating the efficacy and safety of Datroway versus investigator’s choice of chemotherapy (paclitaxel, nab-paclitaxel, capecitabine, carboplatin or eribulin) in patients with previously untreated locally recurrent inoperable or metastatic TNBC for whom immunotherapy was not an option. This included patients whose tumours did not express PD-L1 as well as patients with PD-L1 expressing tumours who could not receive immunotherapy due to prior exposure in early-stage disease, comorbidities or immunotherapy not being accessible in their geography. Enrolment included patients with de novo or recurrent disease, regardless of disease-free interval, and those with poor prognostic factors such as stable brain metastases.
The dual primary endpoints of TROPION-Breast02 are PFS as assessed by BICR and OS. Key secondary endpoints include PFS as assessed by investigator, objective response rate, duration of response, disease control rate, pharmacokinetics and safety.
TROPION-Breast02 enrolled 644 patients at sites in Africa, Asia, Europe, North America and South America. For more information, visit ClinicalTrials.gov.
Datroway
Datroway (datopotamab deruxtecan; datopotamab deruxtecan-dlnk in the US only) is a TROP2-directed ADC. Designed using Daiichi Sankyo’s proprietary DXd ADC Technology, Datroway is one of six DXd ADCs in the oncology pipeline of Daiichi Sankyo, and one of the most advanced programmes in AstraZeneca’s ADC scientific platform. Datroway is comprised of a humanised anti-TROP2 IgG1 monoclonal antibody, developed in collaboration with Sapporo Medical University, attached to a number of topoisomerase I inhibitor payloads (an exatecan derivative, DXd) via tetrapeptide-based cleavable linkers.
Datroway is approved in more than 35 countries/regions worldwide for the treatment of adult patients with unresectable or metastatic HR-positive, HER2-negative (IHC 0, IHC 1+ or IHC 2+/ISH-) breast cancer who have received prior endocrine-based therapy and chemotherapy for unresectable or metastatic disease based on results from the TROPION-Breast01 trial.
Datroway is available in the US under accelerated approval for the treatment of adult patients with locally advanced or metastatic EGFR-mutated non-small cell lung cancer (NSCLC) who have received prior EGFR-directed therapy and platinum-based chemotherapy based on results from the TROPION-Lung05 and TROPION-Lung01 trials. Continued approval for this indication in the US may be contingent upon verification and description of clinical benefit in a confirmatory trial. Datroway is approved in Russia for the same population.
(Press release, AstraZeneca, OCT 19, 2025, View Source [SID1234656785])