PURPOSE: This study aimed to identify the efficacy and toxicity of the FOLFIRI regimen (fluorouracil, leucovorin, and irinotecan) with irinotecan dose escalation plus bevacizumab as first-line chemotherapy for metastatic colorectal cancer (mCRC) via UGT1A1 genotyping. METHODS: We administered bevacizumab plus FOLFIRI with irinotecan dose escalation to treat 70 mCRC patients. The UGT1A1 *1/*1 and *1/*28 genotypes started with a 180- mg/m 2 dose of irinotecan, and UGT1A1 *28/*28 genotype started with a dose of 120 mg/m 2 . The dose of irinotecan was escalated at increasing intervals of 20 to 30 mg/m2 until grade 3/4 adverse events (AEs) occurred. The clinical response rate, toxicity, and survival were analyzed. RESULTS: The clinical response and disease control rates of mCRC patients treated with FOLFIRI plus bevacizumab were significantly better in patients with UGT1A1 *1/*1 and *1/*28 genotypes than in patients with UGT1A1 *28/*28 (P = .006 and P < .001, respectively). Grade 3/4 AEs were significantly more common in mCRC patients with the UGT1A1 *28/*28 genotype (P < .001). Progression-free survival was significantly higher in UGT1A1 *1/*1 and *1/*28 patients (P = .002). mCRC patients who underwent metastasectomy achieved better overall survival than those who did not undergo metastasectomy (P = .015). CONCLUSIONS: Our study showed that mCRC patients with UGT1A1 *1/*1 and *1/*28 genotypes could receive escalated doses of irinotecan to obtain a more favorable clinical outcome without significant AEs.
Lu, C. Y., Huang, C. W., Wu, I. C., Tsai, H. L., Ma, C. J., Yeh, Y. S., … Wang, J. Y. (2015). Clinical implication of UGT1A1 promoter polymorphism for irinotecan dose escalation in metastatic colorectal cancer patients treated with bevacizumab combined with FOLFIRI in the first-line setting. Translational Oncology, 8(6), 474–479. https://doi.org/10.1016/j.tranon.2015.11.002