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DS-8201 Granted Breakthrough Therapy Designation for HER2-Positive Metastatic Breast Cancer

On August 29, the U.S. Food and Drug Administration (FDA) granted Breakthrough Therapy designation to DS-8201, an investigational HER2-targeting antibody-drug conjugate, for the treatment of patients with HER2-positive, locally advanced or metastatic breast cancer who have been treated with trastuzumab and pertuzumab and have disease progression after therapy with ado-trastuzumab emtansine (formerly known as T-DM1), according to an announcement made by Daiichi Sankyo. DS-8201 comprises a humanized HER2 antibody attached to a novel topoisomerase I inhibitor payload by a tetrapeptide linker.

The Breakthrough Therapy designation was based on the results of an ongoing phase I study assessing the safety, tolerability, and preliminary efficacy of DS-8201. In this trial, no dose-limiting toxicities were observed, and the maximum tolerated dose was not reached. Preliminary results of DS-8201 from a subgroup analysis of HER2-expressing metastatic breast cancer pretreated with trastuzumab, pertuzumab, and ado-trastuzumab emtansine were presented by Doi et al at the 2017 ASCO Annual Meeting (Abstract 108).

In addition to Breakthrough Therapy designation, the FDA has granted Fast Track designation to DS-8201 for the treatment of HER2-positive unresectable and/or metastatic breast cancer in patients with disease progression after prior treatment with HER2-targeted therapies including ado-trastuzumab emtansine.