The US Food and Drug Administration (FDA) granted Breakthrough Therapy designation to DS-8201 for the treatment of patients with locally advanced or metastatic, HER2-positive breast cancer who have been treated with trastuzumab, pertuzumab, and have progressed after ado-trastuzumab emtansine (T-DM1).1
DS-8201 is an investigational HER2-targeting antibody drug conjugate (ADC), a targeted therapy for cancer that delivers cytotoxic chemotherapy by means of a linker on the monoclonal antibody that attaches to a specific target on cancer cells.
Breakthrough therapy designation was granted based on evidence from an ongoing 2-part stage 1 dosing trial (ClinicalTrials.gov Identifier: NCT02564900) evaluating the safety and efficacy of DS-8201. A maximum tolerated dose was not reached and no dose-limiting toxicities were reported in the phase 1 study.
Preliminary results demonstrated that patients achieved a 46.7% overall response rate (ORR) (14 of 30 patients) and a 100% disease control rate. Patients who were previously treated with T-DM1 achieved an ORR of 45.7% (16 of 35 patients) and a 100% disease control rate.2