FRIDAY, Sept. 24, 2021 (HealthDay News) — For patients with HER2-positive metastatic breast cancer (mBC) previously treated with trastuzumab and taxane, trastuzumab deruxtecan (T-DXd) yields a significant improvement in progression-free survival compared with trastuzumab emtansine (T-DM1), according to a study presented at the annual meeting of the European Society for Medical Oncology, held virtually from Sept. 16 to 21.
Javier Cortés, M.D., Ph.D., from the UCLA Jonsson Comprehensive Cancer Center in Los Angeles, and colleagues compared the efficacy and safety of T-DXd versus T-DM1 in patients with HER2-positive mBC previously treated with trastuzumab and taxane. A total of 524 patients were randomly assigned in a 1:1 ratio as of May 21, 2021.
The researchers found that the hazard ratio was 0.2840 for progression-free survival (median not reached for T-DXd versus 6.8 months for T-DM1). The estimated 12-month overall survival event rates were 94.1 and 85.9 percent for T-DXd and T-DM1, respectively (hazard ratio, 0.5546; did not cross prespecified boundary for significance). The median treatment duration was 14.3 and 6.9 months with T-DXd and T-DM1, respectively. The rates of treatment-emergent adverse events were similar.
“T-DM1 became the standard of care second-line therapy in 2013 and is the first U.S. Food and Drug Administration-approved antibody drug conjugate. It has a solid safety and efficacy profile,” senior author Sara Hurvitz, M.D., director of the Breast Cancer Clinical Research Program at the UCLA Jonsson Comprehensive Cancer Center, said in a statement. “In the past eight years we have not seen any other therapy try to beat it in a head-to-head trial. Seeing a new therapy demonstrate such a substantial improvement in progression-free survival compared to T-DM1 is really exciting for our patients.”
Several authors disclosed financial ties to pharmaceutical companies, including Daiichi Sankyo and AstraZeneca, which manufacture T-DXd and funded the study.
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