Oncology Drug Approval News Flash: FDA Approves Datopotamab Deruxtecan-dlnk (Datroway, Daiichi Sankyo/AstraZeneca) for 1L Unresectable or Metastatic TNBC (PD-(L)1 Ineligible)

2026-05-30

FDA Approval: Datopotamab Deruxtecan (Datroway) TROP2 ADC for Triple-Negative Breast Cancer

On May 22, 2026, the U.S. Food and Drug Administration (FDA) approved datopotamab deruxtecan-dlnk (Dato-DXd, brand name: Datroway^®), a TROP2-directed antibody-drug conjugate (ADC) jointly developed by Daiichi Sankyo and AstraZeneca, for first-line treatment of adult patients with unresectable or metastatic triple-negative breast cancer (mTNBC) who are not candidates for PD-1/PD-L1 inhibitor therapy. This is the first TROP2-directed ADC approved in the 1L mTNBC setting, providing patients ineligible for immune checkpoint inhibitor therapy—either PD-L1 negative (CPS < 10) or with contraindicating comorbidities—the first targeted regimen demonstrated to outperform standard chemotherapy in both OS and PFS. This article summarizes the design, key efficacy data, safety profile, and regulatory and clinical significance of the pivotal TROPION-Breast02 trial.

TOC

Patient Population

Adults with unresectable or metastatic triple-negative breast cancer (mTNBC)
No prior chemotherapy or other systemic anti-cancer therapy in the unresectable/metastatic setting (1L)
Not candidates for PD-1/PD-L1 inhibitor therapy—including PD-L1 negative (CPS < 10) or patients with comorbidities/autoimmune disease contraindicating immune checkpoint inhibitors
The FDA narrowly defined the patient population; for PD-L1–positive and immunotherapy-eligible patients, pembrolizumab plus chemotherapy remains the standard

Pivotal Trial Overview

The approval is based on data from the Phase 3 TROPION-Breast02 trial (NCT05374512), a multicenter, open-label, randomized study that enrolled 644 patients randomized 1:1 to either datopotamab deruxtecan or investigator’s choice of standard chemotherapy (paclitaxel, nab-paclitaxel, carboplatin, capecitabine, eribulin, etc.).

Item	TROPION-Breast02
Trial ID	NCT05374512
Design	Randomized, open-label, multicenter, Phase 3
N	644
Population	Unresectable/metastatic TNBC, treatment-naive, PD-(L)1 ineligible
Intervention arm	Dato-DXd 6 mg/kg q3w
Control arm	Investigator’s choice standard chemotherapy
Primary endpoints	Dual primary endpoints: progression-free survival (PFS, BICR) and overall survival (OS)
Key secondary endpoints	Objective response rate (ORR), duration of response (DoR), safety

Datopotamab deruxtecan-dlnk is composed of a humanized monoclonal antibody targeting TROP2 (trophoblast cell-surface antigen 2) covalently linked to deruxtecan (DXd), a topoisomerase I inhibitor payload, with a drug-to-antibody ratio (DAR) of approximately 4. TROP2 is a membrane protein overexpressed across multiple solid tumors—particularly breast cancer (TNBC), lung, and urothelial cancers—with reported TROP2 positivity exceeding 80% on TNBC cells. After internalization into TROP2-positive cells and lysosomal cleavage of the linker, the cytotoxic DXd payload is released; DXd also diffuses to adjacent cells, exerting a bystander effect that is expected to be effective against heterogeneous TROP2 tumors.

Until now, 1L mTNBC standard of care for PD-L1 CPS ≥ 10 patients has been pembrolizumab plus chemotherapy (KEYNOTE-355 regimen). However, for PD-L1 CPS < 10 or immunotherapy-ineligible patients (60–70% of mTNBC), chemotherapy alone remained the standard, representing a major unmet need. TROPION-Breast02 specifically targeted this population and is the first Phase 3 trial to establish a targeted therapy for pembrolizumab-ineligible 1L mTNBC.

Key Efficacy Results

Endpoint	Dato-DXd	Chemotherapy	HR / p-value
Median PFS	10.8 months	5.6 months	HR 0.57, p < 0.0001
Median OS	23.7 months	18.7 months	HR 0.79, p = 0.029
ORR	63%	29%	—
Median DoR	12.3 months	7.1 months	—

For PFS, Dato-DXd extended median PFS by 5.2 months over standard chemotherapy (10.8 vs 5.6 months), with a hazard ratio of 0.57—i.e., a 43% reduction in the risk of progression or death (p < 0.0001). This is among the largest PFS improvements ever reported in 1L mTNBC trials, including comparison to immune-ineligible control arms in ASCENT-04 and KEYNOTE-355.

For OS, median survival reached 23.7 vs 18.7 months—a 5-month extension with HR 0.79 (p = 0.029), confirming that the PFS benefit successfully translated into an OS benefit. TNBC is highly aggressive and 1L outcomes drive subsequent-line success; a 5-month OS gain is clinically very meaningful. ORR was 63% vs 29%—more than double—and median DoR was 12.3 vs 7.1 months, demonstrating both depth and durability of response superior to standard chemotherapy.

TROPION-Breast02 is among the few Phase 3 trials to meet both PFS and OS dual primary endpoints, marking a milestone in mTNBC drug development history.

Safety Profile

The safety profile of Dato-DXd is consistent with prior experience in advanced NSCLC and breast cancer (TROPION-Breast01), and the prescribing information includes the following key warnings.

Interstitial lung disease / pneumonitis (ILD)—a class effect shared across DXd-based ADCs. Grade ≥ 3 incidence is in the low single digits, but Grade 5 (fatal) cases have been reported. Routine imaging surveillance and symptom monitoring are essential for early detection
Ocular adverse events—dry eye, keratitis, visual impairment. A relatively frequent and distinctive profile for Dato-DXd
Stomatitis / oral mucositis—Grade ≥ 3 in approximately 5–10%; preventive oral care interventions are important
Embryo-fetal toxicity—contraindicated in pregnancy or those who may become pregnant

Adverse Event	All Grades	Grade ≥3
Nausea	~70%	~5%
Stomatitis / oral mucositis	~55%	~8%
Fatigue	~50%	~5%
Alopecia	~40%	—
Dry eye / keratitis	~30%	~2%
ILD / pneumonitis	~9%	~3% (Grade 5 ≤ 1%)

Compared with the competing TROP2 ADC sacituzumab govitecan (Trodelvy), Dato-DXd shows less myelosuppression (neutropenia) and diarrhea, but more stomatitis, ocular AEs, and ILD. Future drug selection will weigh patient profiles (history of oral/ocular disease, pulmonary function, etc.) against the contrasting toxicity profiles.

Regulatory Significance and Clinical Positioning

The significance of this approval can be summarized along three axes.

(1) First targeted therapy for PD-(L)1–ineligible 1L mTNBC. Since KEYNOTE-355 established pembrolizumab + chemotherapy for PD-L1 CPS ≥ 10 patients, the CPS < 10 / immunotherapy-ineligible cohort (60–70% of mTNBC) has been a development void. Dato-DXd provides the first option clinically superior to chemotherapy for this large patient segment, bifurcating the 1L mTNBC standard into immunotherapy-based and ADC-based pathways.

(2) Clinical establishment of TROP2 ADCs and the competitive landscape vs. sacituzumab govitecan. Sacituzumab govitecan (Trodelvy, Gilead) had previously won approval in 2L+ TNBC (ASCENT trial). With Dato-DXd’s 1L approval, TROP2 ADC positioning advances from 2L to 1L. Key clinical questions now become: (a) what to use in 2L after 1L Dato-DXd, (b) whether Trodelvy can maintain its 2L survival benefit. Daiichi Sankyo/AstraZeneca versus Gilead in TROP2 ADCs is forming a competitive dynamic comparable to HER2 ADCs (T-DXd vs T-DM1).

(3) Strategic significance of ADC pipeline expansion. Daiichi Sankyo’s DXd platform—T-DXd (HER2), Dato-DXd (TROP2), Patritumab deruxtecan (HER3), and others—now has two DXd-based ADCs approved in large indications. Combined with HER3-DXd development in breast/NSCLC and the recent T-DXd early breast cancer expansion (DESTINY-Breast05/11, approved May 15), the DXd platform is consolidating as the leading ADC platform across tumor types, targets, and treatment lines. This approval further strengthens the company’s global ADC leadership.

My Thoughts and Future Outlook

This approval reshapes the 1L mTNBC landscape in what had been the “valley” of pembrolizumab-ineligible patients. A 5.2-month PFS gain, 5-month OS gain, and more than doubled ORR—delivered in patients excluded from PD-(L)1 inhibitor therapy—reframe the long-standing narrative that “PD-L1 negative means poor prognosis.” Daiichi Sankyo/AstraZeneca delivered the HER2-DXd early breast cancer approval (May 15) and the TROP2-DXd 1L mTNBC approval just one week later, underscoring the DXd platform’s clinical depth and development velocity.

However, ILD and ocular AEs—Dato-DXd’s distinctive toxicities—will require dedicated management infrastructure from day one. Breast cancer patients face long treatment durations; ILD imaging surveillance, ophthalmology coordination for dry eye and keratitis, and oral mucositis prevention will be foundational to safe deployment alongside the establishment of ADC specialty clinics. Approval at the 1L setting—high patient volume—will test real-world toxicity management maturity. Clinical selection criteria for Dato-DXd versus sacituzumab govitecan (prior treatment history, toxicity profile, patient lifestyle) will likely crystallize from real-world evidence over the next 1–2 years.

Next-wave developments include: (1) Dato-DXd expansion into early breast cancer (neoadjuvant/adjuvant), (2) combination with pembrolizumab in PD-(L)1–eligible TNBC, (3) optimal positioning in HER2-low / HER2-ultralow / HR+ breast cancer, (4) elucidation of TROP2 expression (IHC scores) and efficacy correlation, (5) mechanistic dissection of bystander effect modulation by tumor microenvironment. As an opening milestone of the era when “ADC becomes 1L standard in breast cancer,” this approval will likely be remembered.

※This article is an independent summary by Morningglorysciences based on FDA approval documents, Daiichi Sankyo/AstraZeneca press releases, and TROPION-Breast02 presentations. Treatment decisions should always reference the original publications, the latest prescribing information, and regional clinical guidelines.

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Author of this article

Morning Glory Sciences

After completing graduate school, I studied at a Top tier research hospital in the U.S., where I was involved in the creation of treatments and therapeutics in earnest. I have worked for several major pharmaceutical companies, focusing on research, business, venture creation, and investment in the U.S. During this time, I also serve as a faculty member of graduate program at the university.