Overall response rate (ORR) in STEAM, a randomized, open-label, phase 2 trial of sequential and concurrent FOLFOXIRI-bevacizumab (BEV) vs FOLFOX-BEV for the first-line (1L) treatment (tx) of patients (pts) with metastatic colorectal cancer (mCRC).

492 Background: 3-drug chemotherapy (CT) + BEV (cFOLFOXIRI-BEV) significantly improved efficacy vs FOLFIRI-BEV for 1L mCRC tx, but safety and the impact of subsequent fluoropyrimidine-BEV maintenance tx require further definition. The phase 2 STEAM (NCT01765582) trial assessed efficacy of 1L cFOLFOXIRI-BEV vs FOLFOX-BEV and safety of alternating 2-drug CT (FOLFOX and FOLFIRI) + BEV tx monthly in a sequential sFOLFOXIRI-BEV regimen. Methods: Pts with unresectable, previously untreated mCRC were randomized 1:1:1 to BEV-containing (5 mg/kg) arms (cFOLFOXIRI, sFOLFOXIRI [alternating FOLFOX and FOLFIRI every 4 weeks {q4w}], or FOLFOX q3w) in a 4–6 month induction phase, followed by BEV-containing maintenance tx. Stratification factors included extent of metastatic disease and tumor location. Primary objectives: 1L ORR, 1L progression-free survival (PFS), safety. Secondary objectives: resection and conversion to resectable disease rates, time to 2L PFS, overall survival. ORR was tested with a 1-sided alpha of 5...