Effect of Digoxin on Clusters of Circulating Tumor Cells (CTCs) in Breast Cancer Patients.

Background: Circulating tumor cells (CTCs) are found in the blood of cancer patients as single CTCs and CTC clusters. The presence of CTC clusters is associated with tumor progression and with a bad prognosis in various cancer types1,2. In breast cancer, a pre-clinical model demonstrated that Na/K-ATPase inhibitors such as digoxin could dissolve CTC clusters and reduce metastasis3.

DICCT is a single-arm, therapeutic exploratory phase I study that investigates whether the cardiac glycoside digoxin can disrupt CTC clusters in advanced or metastatic breast cancer patients (BASEC ID2019-00637 and NCT03928210.)

Brief Summary DICCT Study: CTC cluster share several properties that commonly feature stem cell biology which drive metastases formation. Preclinical data shows that CTC clusters can be disaggregated into single cells by the treatment with cardiac glycosides such as digoxin.

DICCT is conducted as multi-centric study in three Swiss centres: The University Hospital Basel (USB) with Prof. Dr. med. Christain Kurzeder as Sponsor Investigator, at the Kantonsspital Baselland (KSBL Liestal) with PD Dr. med. Marcus Vetter as Coordinating Investigator and Dr. med. Angela Kohler as Principal Investigator and at the University Hospital Zurich (UKZ) with Dr med. Bich Doan Nguyen-Sträuli as Principal Investigator and Dr. med. Alexander Ring as local Investigator.

At all study sites, patients with advanced or metastatic breast cancer in whom CTC clusters are found are enrolled into the study. Patients receive an individualized daily maintenance dose of digoxin adapted to their kidney function. Blood samples for analyses of digoxin serum level and CTC cluster size are drawn at specified time points.

The study and subsequent analyses were made possible through a close collaboration with Prof. Dr. Nicola Aceto and his team www.theacetolab.ch at the ETH Zurich.

In December 2022 the digoxin study was acknowledged in Nature Medicine (Volume 28 | December 2022 | 2444–2448 | 2448) among the 11 clinical trials that will shape medicine in 2023.

The Swiss GO Trial Group is proud to provide its administrative support and input in such an important study (Swiss-GO-07). For further information, please also contact the Swiss-GO Office at This email address is being protected from spambots. You need JavaScript enabled to view it.