A Multicenter Clinical Phase II Study of FOLFOXIRI Plus Bevacizumab as First-line Therapy in Patients With Metastatic Colorectal Cancer: QUATTRO Study

FOLFOXIRI plus bevacizumab is an effective for Asian metastatic colorectal cancer patients and the safety profile is manageable by adopting appropriate measures, even if severe neutropenia and febrile neutropenia develop at a higher frequency in ethnic Asian patients with UGT1A1*6 and *28 polymorphism. Background: FOLFOXIRI (Fluorouracil, folinate, oxaliplatin, and irinotecan) plus bevacizumab improved progression-free survival (PFS) and overall survival in patients with metastatic colorectal cancer (mCRC), compared with FOLFIRI (fluorouracil, folinate, and irinotecan) plus bevacizumab, but significantly increased the incidences of adverse events. The efficacy and safety profiles of FOLFOXIRI plus bevacizumab in ethnic Asian patients have not been established yet. Patients and Methods: This study was an open-label, single-arm, multi-centered phase II prospective clinical trial in patients with mCRC who received FOLFOXIRI plus bevacizumab. The primary endpoint was the PFS rate at 10 months. Secondary endpoints included overall survival, response rate, and safety. Results: A total of 69 patients received FOLFOXIRI plus bevacizumab as induction therapy and were assessed for efficacy and safety. The PFS rate at 10 months was 75.2% and the median PFS was 13.3 months. Complete response and partial response were achieved in 2 (2.9%) and 47 patients (69.1%), respectively. Grade 3 and 4 adverse events with incidence rates exceeding 20% were neutropenia (72.5%), hypertension (34.8%), leucopenia (33.3%), and febrile neutropenia (21.7%). Significantly more patients with grade 4 neutropenia had single-heterozygous UGT1A1*1/*6 or *1/*28 (46.2%) than UGT1A1 wild-type genotype (*1/*1) (13.3%) (P =.004). Conclusions: FOLFOXIRI plus bevacizumab is considered an effective first-line regimen that improves the outcome of patients with mCRC regardless of ethnicity. In Asian patients, utmost attention should be paid to the possible onset of severe neutropenia or febrile neutropenia attributed to different types of UGT1A1*6 and *28 polymorphism, when FOLFOXIRI plus bevacizumab is administered.