Raltitrexed Chemotherapy Regimen Plus Bevacizumab as Second-Line Treatment for Metastatic Colorectal Cancer: A Prospective Multicenter Phase II Trial

Abstract

Objectives Clinical studies have shown that bevacizumab plus chemotherapy significantly improves efficacy in metastatic colorectal cancer (mCRC). This prospective study aims to investigate the efficacy and safety of changing second-line treatment to raltitrexed-based chemotherapy regimens plus bevacizumab in mCRC patients who have failed the first-line fluorouracil-based chemotherapy regimen with or without bevacizumab/cetuximab. Methods This is a prospective, open-label, multicenter, phase II clinical study. A total of 100 patients with mCRC after failure of the first-line fluorouracil-based chemotherapy regimen with or without bevacizumab/cetuximab were enrolled from November 2016 to October 2021, and received second-line raltitrexed-based chemotherapy regimen plus bevacizumab. Patients were treated for 6 cycles, and efficacy evaluation over stable disease were followed by maintenance treatment of bevacizumab and raltitrexed until disease progression or intolerable toxicity. The primary endpoint was progression-free survival (PFS). Secondary endpoints included overall survival (OS), objective response rate (ORR), disease control rate (DCR), safety, and toxicity. Results Ninety-four patients were treated with SALIRI (raltitrexed + irinotecan) plus bevacizumab, and six patients with SALOX (raltitrexed + oxaliplatin) plus bevacizumab. Median PFS was 8.4 (95% CI: 6.2-11.0) months, including 8.2 (95% CI 6.2, 11.0) months in the SALIRI group and 11.6 (95% CI 3.1, NA) months in the SALOX group. Median OS was 17.6 (95% CI 15.2, 22.0) months in the SALIRI group and 17.1 (95% CI 4.1, NA) months in the SALOX group. ORR and DCR were 25.5% and 87.2% in the SALIRI group, and 33.3% and 83.3% in the SALOX group, respectively. A low incidence of grade 3-4 adverse events was observed. Conclusions Raltitrexed-based chemotherapy regimens plus bevacizumab improved survival duration in mCRC patients with failed first-line therapy. Therefore, treatment with raltitrexed-based chemotherapy regimens plus bevacizumab could be a superior therapeutic option for second-line chemotherapy in mCRC ( ClinicalTrials.gov registration number: NCT03126071).