DETECT III – A multicenter, randomized, phase III study to compare standard therapy alone versus standard therapy plus lapatinib in patients with initially HER2-negative metastatic breast cancer and HER2-positive circulating tumor cells

Background: Despite a HER2-negative primary tumor approximately 20–30% of patients develop HER2-positive metastases (Zidan et al. 2005; Tewes et al. 2009). As previously described in the DETECT I trial (Fehm et al. 2010) determination of HER2 status on circulating tumor cells (CTCs) is one option for re-evaluating HER2-status in the metastatic setting. Currently it is unclear if HER2-targeted therapy based on the assessment of HER2-status of CTCs reveals a clinical benefit. Trial design: DETECT III is a randomized, open-label, two arm phase III study comparing standard treatment alone vs. standard treatment plus HER2-targeted therapy with lapatinib in HER2-negative metastatic breast cancer patients with HER2-positive CTCs.