Trastuzumab Deruxtecan (Enhertu) indication extension for HER2 Low Metastatic Breast Cancer with HR Positive and HR Negative Disease submitted to EMA

European Medicines Agency (EMA) has validated the Type II Variation application for trastuzumab deruxtecan (Enhertu) as monotherapy for the treatment of adult patients with unresectable or metastatic HER2 low (immunohistochemistry (IHC) 1+ or IHC 2+/in-situ hybridization (ISH)-negative) breast cancer who have received a prior systemic therapy in the metastatic setting or developed disease recurrence during or within six months of completing adjuvant chemotherapy. Patients with hormone receptor (HR) positive breast cancer must additionally have received or be ineligible for endocrine therapy.

Trastuzumab deruxtecan is a specifically engineered HER2 directed antibody drug conjugate (ADC) being jointly developed and commercialized by Daiichi Sankyo and AstraZeneca.

This application is based on data from the DESTINY-Breast04 trial, a global, randomized, open-label, pivotal phase 3 trial evaluating the efficacy and safety of trastuzumab deruxtecan (5.4 mg/kg) versus physician’s choice of chemotherapy (capecitabine, eribulin, gemcitabine, paclitaxel or nab-paclitaxel) in patients with HR positive or HR negative, unresectable and/or metastatic breast cancer with low HER2 expression previously treated with one or two prior lines of chemotherapy. Patients were randomized 2:1 to receive either trastuzumab deruxtecan or chemotherapy.

The primary endpoint of DESTINY-Breast04 is PFS in patients with HR positive disease based on blinded independent central review (BICR). Key secondary endpoints include PFS based on BICR in all randomized patients (HR positive and HR negative disease), OS in patients with HR positive disease and OS in all randomized patients (HR positive and HR negative disease). Other secondary endpoints include PFS based on investigator assessment, objective response rate based on BICR and on investigator assessment, duration of response based on BICR and safety. DESTINY-Breast04 enrolled 557 patients at multiple sites in Asia, Europe and North America. 

Validation of the application means that it commences the scientific review process by the EMA’s Committee for Medicinal Products for Human Use (CHMP). Approval can be expected in Q1 2023.