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For a subset of patients with inoperable or metastatic HR-positive/HER2-negative breast cancer, treatment with datopotamab deruxtecan improved progression-free survival.
Dato-DXd demonstrated significant improvements in progression-free survival for patients with inoperable or metastatic HR-positive/HER2-negative breast cancer.
Datopotamab deruxtecan (Dato-DXd) demonstrated significant improvements in progression-free survival (PFS; time a person lives without their disease getting worse) with a manageable safety profile compared with chemotherapy in patients with previously treated inoperable or metastatic HR-positive, HER2-negative breast cancer, study findings demonstrated.
“[These] results support Dato-DXd as a novel treatment option for patients with inoperable/metastatic HR-positive/HER2-negative breast cancer who have received one to two previous lines of chemotherapy in this setting,” researchers wrote in the study published in the Journal of Clinical Oncology.
In the TROPION-Breast-1 study, researchers compared Dato-DXd with chemotherapy in patients with inoperable or metastatic HR-positive, HER2-negative breast cancer with disease progression on endocrine therapy, those who were considered unsuitable for endocrine therapy and were previously treated with one to two lines of chemotherapy in the inoperable/metastatic setting. The majority of patients (82.5%) had previously received CDK4/6 inhibitor therapy (treatment that targets specific proteins involved in cancer cell growth).
After a median follow-up of 10.8 months, treatment with Dato-DXd showed a 37% reduction in the risk of disease progression or death compared with chemotherapy. While data on overall survival (time from the start of treatment when a patient with cancer is still alive) were not mature at the time it was assessed (meaning there was a lack of data to draw a meaningful conclusion), a trend favoring Dato-DXd was observed.
Dato-DXd demonstrated a longer median PFS than chemotherapy (6.9 months versus 4.9 months). A higher proportion of patients in the Dato-DXd arm remained progression-free compared with the chemotherapy arm at nine months (37.5% versus 18.7%) and 12 months (25.5% versus 14.6%). Of note, improvements in PFS were consistent across several patient subgroups including geographic region, previous lines of therapy and previous use of CDK4/6 inhibitors.
Additionally, the rate of grade 3 (severe) or worse side effects was lower in patients treated with Dato-DXd compared with those treated with chemotherapy (20.8% versus 44.7%). The most common treatment-related side effects in the Dato-DXd group were nausea and stomatitis (swelling and sores inside the mouth). For patients treated with chemotherapy, the most common treatment-related side effect was neutropenia (a low count of neutrophils, a type of white blood cell).
Serious treatment-related side effects occurred in 5.8% of patients assigned to Dato-DXd and 9.1% of patients assigned to chemotherapy. In addition, treatment-related side effects led to dose reductions in 20.8% of patients treated with Dato-DXd and 30.2% of those treated with chemotherapy, with dose interruptions in 11.9% and 24.5%, respectively. Treatment discontinuations due to side effects were similar, occurring at 2.5% in the Dato-DXd group and 2.6% in the chemotherapy group.
“Datopotamab Deruxtecan Versus Chemotherapy in Previously Treated Inoperable/Metastatic Hormone Receptor–Positive Human Epidermal Growth Factor Receptor 2–Negative Breast Cancer: Primary Results From TROPION-Breast01” by Dr. Aditya Bardia, et al. Journal of Clinical Oncology.
“Overall, Dato-DXd demonstrated a statistically significant and clinically meaningful improvement in PFS and a favorable and manageable safety profile compared with [chemotherapy] for a patient population with previously unmet need for more efficacious and less toxic therapies,” study authors concluded. “Further phase 3 studies are now in progress evaluating Dato-DXd in other breast cancer settings, including early and metastatic [triple-negative breast cancer], either as monotherapy [treatment with a single drug] or in combination with immunotherapy [treatment that stimulates the immune system to fight cancer].”
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