Daiichi Sankyo, Inc. issued the following announcement on Jan. 14.
Daiichi Sankyo Company, Limited (hereafter, Daiichi Sankyo) announced that the first patient has been dosed in DESTINY-Breast04, a global pivotal phase 3 study evaluating the safety and efficacy of [fam-] trastuzumab deruxtecan (DS-8201), an investigational HER2 targeting antibody drug conjugate (ADC), in patients with HER2 low, unresectable and/or metastatic breast cancer previously treated with standard chemotherapy.
Over 40 percent of all breast cancers express low levels of HER2 as a cell surface antigen (IHC 2+/ISH- or IHC 1+), but no anti-HER2 therapies are currently approved for these low expressing tumors.1,2 In current clinical practice, these patients are classified and treated according to guidelines for HER2 negative breast cancer and according to the hormone receptor (HR) status.2 Many patients eventually progress on current treatments to a point where limited options are available.2 For HER2 negative, HR positive breast cancer, guidelines recommend endocrine therapy plus a cyclin-dependent kinase (CDK) 4/6 inhibitor, and, if tumors become resistant, physician’s choice of single-agent chemotherapies is recommended.2 For HER2 negative, HR negative breast cancer (“triple negative"), treatment is typically with physician’s choice of single-agent chemotherapies.2
“DESTINY-Breast04 has been initiated based on preliminary phase 1 study results to determine whether [fam-] trastuzumab deruxtecan could serve as a targeted therapy option for patients with HER2 low metastatic breast cancer that progresses after standard chemotherapy, regardless of HR status,” said Gilles Gallant, BPharm, PhD, Vice President, DS-8201 Global Team Leader, Oncology Research and Development, Daiichi Sankyo. “HER2 targeting agents have improved survival rates for HER2 positive breast cancer, but none have been approved in HER2 low expressing tumors. DESTINY-Breast04, our third phase 3 breast cancer trial with [fam-] trastuzumab deruxtecan, has potential to define a new patient population for HER2 targeted treatment.”