Prospective open uncontrolled phase I study to define a well-tolerated dose of oral artesunate as add-on therapy in patients with metastatic breast cancer (ARTIC M33/2).

Purpose: The antimalarial drug artesunate (ART) is a promising candidate for cancer treatment as it displays anticancer effects in various models. While in short-term treatment of malaria, an excellent safety profile has been found for ART, the potential long-term treatment of cancer patients demands a phase I dose-finding clinical trial determining the daily ART dose which would be well tolerated as add-on therapy.

Methods: Patients with metastatic breast cancer were to receive either 100 or 150 or 200 mg oral ART daily as add-on to their guideline-based oncological therapy for a study period of four weeks with frequent clinical and laboratory monitoring until 4-8 weeks thereafter.