A Study of Trifluridine/Tipiracil in Triple Negative Metastatic Breast Cancer

This is an open-label, single arm, multi-stage, phase II trial of Trifluridine/tipiracil (TAS-102) as a palliative treatment for patients with metastatic triple negative breast cancer who have failed both a taxane and anthracycline or have contraindications to these agents. The trial will begin with a safety run-in of 10 patients treated as follows: Cycle 1: Trifluridine/tipiracil administered at 30 mg/m2 orally bid, 5 days per week, with 2 days of rest, for 2 weeks, followed by 14 day rest. Intra-patient dose escalation to 35 mg/m2 orally bid, 5 days per week, with 2 days of rest, for 2 weeks, followed by 14 day rest for subsequent cycles in the absence of dose limiting toxicities. As long as at least 80% of patients tolerate dose escalation, the trial will proceed to the next stage. Patients enrolled in stages I and II will start Trifluridine/tipiracil at 35 mg/m2 orally bid, 5 days per week, with 2 days of rest, for 2 weeks, followed by 14 day rest.