Therapeutic intervention based on circulating tumor cell phenotype in metastatic breast cancer: concept of the DETECT study program

PURPOSE: The aim of the ongoing DETECT study program is to evaluate therapeutic intervention based on phenotypes of circulating tumor cells (CTC) in patients with metastatic breast cancer (MBC). Currently (as of July 2015) more than half of the projected about 2000 patients with MBC have already been screened for CTC.

METHODS: Women with HER2-negative primary tumor and presence of CTC are recruited into different DETECT trials according to the HER2-phenotype of CTC. Patients with HER2-positive CTC are randomized to treatment with physicians' choice therapy (standard chemo- or endocrine therapy) with or without additional HER2-targeted therapy with lapatinib in the DETECT III trial. In DETECT IVa, postmenopausal patients with hormone-receptor positive primary cancer and HER2-negative CTC receive everolimus and standard endocrine therapy. For women with HER2-negative CTC and triple negative MBC or hormone-receptor positive tumor and indication for chemotherapy, a treatment with eribulin is offered (DETECT IVb). The clinical efficacy is investigated by CTC-Clearance and progression-free survival (PFS). The DETECT V/CHEVENDO trial extends the DETECT study program for women with HER2-positive and hormone-receptor positive MBC. The primary objective of this trial is to compare safety and quality of life (QoL) as assessed by the occurrence of adverse events in patients treated with dual (trastuzumab plus pertuzumab) HER2-targeted therapy plus either endocrine or chemotherapy. The translational research projects of the DETECT study program focus on further molecular characterization of CTC and evaluation of markers for their suitability to predict treatment response and to facilitate the development of more personalized treatment options.