Breakthrough Therapy Designation Granted for T-DXd in HER2-Positive Breast Cancer
Posted: Monday, October 11, 2021
On October 4, the U.S. Food and Drug Administration (FDA) granted fam-trastuzumab deruxtecan-nxki (T-DXd), a HER2-directed antibody-drug conjugate, Breakthrough Therapy designation for the treatment of adults with unresectable or metastatic HER2-positive breast cancer who have received one or more prior anti–HER2-based regimens. T-DXd is currently approved for the treatment of adults with unresectable or metastatic HER2-positive breast cancer who have had two or more prior anti–HER2-based regimens in the metastatic setting in the United States, Japan, the European Union, and several other countries.
The FDA’s decision was based on favorable results from the phase III DESTINY-Breast03 clinical trial, presented during the European Society for Medical Oncology (ESMO) Congress 2021. In patients with HER2-positive unresectable and/or metastatic breast cancer previously treated with trastuzumab and a taxane, a 72% reduction in the risk of disease progression was observed with T-DXd compared with T-DM1 (ado-trastuzumab emtansine). Additionally, the confirmed objective response rate more than doubled in the T-DXd arm versus the T-DM1 arm (79.7% vs. 34.2%).
Almost all patients (94.1%) treated with T-DXd were alive after 1 year. In contrast, 85.9% of patients administered with T-DM1 were alive after 1 year. In addition, there were no new safety concerns raised during the trial, along with no reported grade 4 or 5 treatment-related interstitial lung disease events. Overall, the safety profile of T-DXd was consistent with previous clinical trials.
