Phase III trial of metronomic capecitabine maintenance after standard treatment in operable triple-negative breast cancer (SYSUCC-001).

507 Background: Triple-negative breast cancer (TNBC) has a relatively high relapse rate and poor outcome after standard therapy among all subtypes of breast cancer. Effective strategies to reduce risk of relapse and death are unmet medical needs. Methods: In this phase III trial, patients with operable TNBC were randomly assigned to receive metronomic capecitabine (650 mg/m2 twice daily continuously for one year) as maintenance therapy or observation after standard local and systemic treatment for curative intent. The primary end point was disease-free survival (DFS). Secondary end points included distant disease-free survival (DDFS), overall survival (OS) and safety. Results: A total of 434 patients were randomly assigned to capecitabine group (n = 221) or observation group (n = 213). At a median follow-up of 56.5 months, 5-year DFS was significantly better in capecitabine group than in observation group (83% vs. 73%, HR, 0.63; 95% CI, 0.42 to 0.96; p = 0.027). 5-year DDFS was also significantly better in capecitabine group than in observation group (85% vs. 76%, HR, 0.56; 95% CI, 0.37 to 0.90; p = 0.016). However, 5-year OS was not significantly different between two groups (85% vs. 81%, HR, 0.74; 95% CI, 0.47 to 1.18; p = 0.203). Two hundred and two (91.4%) of patients completed one year of capecitabine therapy as planned. The most common capecitabine-related adverse events were hand-foot syndrome (46%), leukopenia (24%), Hyperbilirubinemia (13%), gastrointestinal pain (7%) and elevated serum transaminases (5%). Conclusions: Maintenance therapy with metronomic capecitabine for one year following standard treatment significantly improved DFS in operable TNBC, which was safe and well tolerated. (SYSUCC-001, Clinical trial information: NCT01112826 .