TAS102 in Patients With ER-positive, HER2-negative Advanced Breast Cancer

"Study medication should be started within 3 days after completion of screening and continue until a study treatment discontinuation criterion is met.~Trifluridine/tipiracil will be administered orally BID on days 1 through 5, with the first dose administered in the morning of day 1 of each cycle and the last dose administered in the evening of day 5, followed by a recovery period from day 6 through day 7. Trifluridine/tipiracil will be administered orally BID on days 8 through 12, with the first dose administered in the morning of day 8 of each cycle and the last dose administered in the evening of day 12, followed by a recovery period from day 13 through day 28. Each cycle will be 28 days."