38MO - Datopotamab deruxtecan (Dato-DXd) vs chemotherapy (CT) in patients (pts) with pre-treated inoperable/metastatic hormone receptor-positive, HER2-negative (HR+/HER2–) breast cancer (BC): Results from TROPION-Breast01 China cohort

Background

In the global, phase III TROPION-Breast01 study (NCT05104866), the TROP2-directed antibody-drug conjugate Dato-DXd showed statistically significant and clinically meaningful improvement in progression-free survival (PFS) by blinded independent central review (BICR) vs investigator’s choice of CT (ICC) (HR 0.63 [95% CI 0.52‒0.76]; p<0.0001) (Bardia et al, ESMO 2023) in pts with pre-treated inoperable/metastatic HR+/HER2–BC. Here we present efficacy and safety data from pts enrolled in mainland China.

Methods

Adult pts with inoperable/metastatic HR+/HER2– BC who had experienced progression on endocrine therapy (ET) and for whom ET was unsuitable and who had received 1‒2 prior lines of systemic CT were randomised 1:1 to Dato-DXd (6 mg/kg Q3W) or ICC (capecitabine/eribulin/gemcitabine/vinorelbine) until progression or unacceptable toxicity. Dual primary endpoints were PFS by BICR and overall survival (OS).

Results

Of the 732 pts in the full analysis set, 83 (11.3%) were randomised in China (Dato-DXd: 44; ICC: 39). Median age (range) was 50 (30–73) vs 48 (33–70) yrs in the Dato-DXd vs ICC arms. Treatment was ongoing for 10 vs 3 patients in the Dato-DXd vs ICC arms at data cutoff (DCO: 17Jul23). Median PFS by BICR was 8.1 vs 4.2 months with Dato-DXd vs ICC (HR 0.54 [95% CI 0.30‒0.96]). OS data were not mature at this DCO, however, a trend for improvement favouring Dato-DXd over ICC was observed (HR 0.43 [95% CI 0.17‒1.01]). Confirmed objective response rate (by BICR) was 38.6% (17/44; all partial responses [PR]) with Dato-DXd vs 18.0% (7/39; all PR) with ICC. Safety is summarised in the table. Most common TRAEs were nausea (47.7%) with Dato-DXd and anaemia (52.8%) with ICC.

Conclusions

In this China cohort, Dato-DXd showed improved efficacy with a manageable safety profile compared with ICC, consistent with results in the overall global population Table: 38MO

AEs, adverse events; TRAEs, treatment-related AEs; ILD, interstitial lung disease

Clinical trial identification

NCT05104866.

Editorial acknowledgement

Medical writing support for the development of this abstract, under the direction of the authors, was provided by Ella Spencer, MSci of Ashfield MedComms (London, UK), an Inizio company.

Legal entity responsible for the study

AstraZeneca PLC in collaboration with Daiichi Sankyo.

Funding

AstraZeneca PLC in collaboration with Daiichi Sankyo.

Disclosure

S. Wang: Financial Interests, Personal, Advisory Role, Consulting or advisory role: AstraZeneca, Daiichi Sankyo; Financial Interests, Personal, Speaker’s Bureau: Pfizer, Roche, AstraZeneca, Novartis, Lilly; Financial Interests, Personal, Research Funding: Pfizer, AstraZeneca. A. Bardia: Financial Interests, Personal, Advisory Role, Consulting or advisory role (personal): Novartis, Genentech, Pfizer, Merck, Sanofi, Daiichi Sankyo, AstraZeneca, Lilly, Gilead Sciences, Menarini, Mersana; Financial Interests, Institutional, Advisory Board, Consulting or advisory role (to institution): Novartis, Genetech/Roche, Pfizer, Radius Health, Innocrin Pharma, Lilly, Gilead Sciences, Menarini; Financial Interests, Personal, Advisory Board, Research funding (to institution): Genentech, Novartis, Pfizer, Merck, Sanofi, Radius Health, Immunomedics, AstraZeneca, Daiichi Sankyo. B. Xu: Financial Interests, Personal, Speaker’s Bureau: AstraZeneca, Pfizer, Roche; Financial Interests, Personal, Advisory Role, Consulting or advisory role: AstraZeneca, Novartis. All other authors have declared no conflicts of interest.