Impact of the prior chemotherapy with two different fluoropyrimidines on the efficacy of CapeIRI or FOLFIRI in metastatic colorectal cancer: An exploratory analysis of the phase III AXEPT trial

711 Background: Modified CapeIRI (irinotecan 200 mg/m2 on day 1, capecitabine 1600 mg/m2 on days 1–14 every 3 weeks) with or without bevacizumab (± BV) has shown non-inferiority of overall survival compared with FOLFIRI ± BV based on the phase III study, AXEPT, as second-line chemotherapy for patients with mCRC. In this exploratory analysis of the AXEPT trial, we evaluated the impact of the prior chemotherapy with two different fluoropyrimidine backbones (fluorouracil and leucovorin vs oral fluoropyrimidine) on the efficacy of CapeIRI and FOLFIRI. Methods: Patients were randomized to receive standard FOLFIRI ± bevacizumab or modified CapeIRI ± bevacizumab after failure to fluoropyrimidine-based chemotherapy in the AXEPT study. Prior fluoropyrimidine backbones were categorized into oral fluoropyrimidine-based (eg, capecitabine or S-1) regimen (oral 5-FU group) and fluorouracil and leucovorin-based regimen (infusional 5-FU group). Assessed endpoints included overall survival, progression-free survival, response rate, and safety. Results: Prior fluoropyrimidine backbone was available for 642 patients among all 650 randomized patients (oral 5-FU group in 291, and infusional 5-FU group in 351). Median overall survival was 17.0 and 16.7 months for FOLFIRI ± BV and CapeIRI ± BV in the prior oral 5-FU group, and 14.9 and 16.7 months for FOLFIRI ± BV and CapeIRI ± BV in the prior infusional 5-FU group. Median progression-free survival was 7.9 and 8.6 months for FOLFIRI ± BV and CapeIRI ± BV in the prior oral 5-FU group, and 6.8 and 8.3 months for FOLFIRI ± BV and CapeIRI ± BV in the prior infusional 5-FU group. Conclusions: There was no significant difference in the efficacy of CapeIRI or FOLFIRI regardless of prior fluoropyrimidine backbones. Therefore, CapeIRI ± BV could also be effective for patients after failure of oral fluoropyrimidine-based chemotherapy (eg, CapeOX ± BV). Clinical trial information: NCT01996306. [Table: see text]