Phase II trial of combined chemotherapy with S-1, oral leucovorin, and bevacizumab in heavily pretreated patients with metastatic colorectal cancer.

627 Background: Regorafenib improves survival in refractory metastatic colorectal cancer (mCRC), but alternative chemotherapy is required to avoid severe toxicity. S-1+oral leucovorin (SL) has shown promising results in untreated mCRC without severe toxicity. TML trial demonstrated that continuation of bevacizumab (Bev) after progression prolongs overall survival. Thus, we hypothesized that combination chemotherapy of SL/Bev would be beneficial; we conducted a single-center phase II trial to assess the efficacy and safety of SL/Bev as a salvage therapy in mCRC. Methods: Major eligibility criteria were: mCRC with confirmed adenocarcinoma diagnosis; age > 20 years; ECOG performance status, 0–2; and progression after administration or intolerance to approved drugs for mCRC (5-FU, oxaliplatin, irinotecan, Bev, and anti-EGFR antibody, if KRAS wild-type). S-1 (80–120 mg/body) and leucovorin (25 mg) were orally administered for 1 week followed by 1 week rest. Bev (5 mg/kg) was administered on day 1 of every 2-we...