Clinical Trial of Combination Chemotherapy With Aflibercept in Patients With Advanced Colorectal Cancer

Statistical hypotheses and sample size calculation: It is estimated that the progression-free survival (PFS) rate at 1year will be improved from 33% (corresponding to a median PFS of 7.5 months \[null hypothesis\]) to 47% (corresponding to a median PFS of 11 months \[alternative hypothesis\]) with the combination of first-line Folinic acid/5-Fluorouracil/Irinotecan (FOLFIRI) plus aflibercept therapy in patients with metastatic colorectal cancer (mCRC). Using the one-stage Fleming's design, in order to reject the null hypothesis in a one-sided test with a type I error of 5% and power 80%, 73 patients will be needed to enter the study. Analysis population: * Intent-to-treat (ITT) population: all patients who will have given their informed consent and who will have been correctly registered to the study * Evaluable population for tumor response: all treated patients, without major protocol deviation, with at least one tumor evaluation while on treatment (except for early disease progression or death) and evaluable for response * Safety population: the subset of the ITT population that took at least one dose of study medication Primary analysis: The primary efficacy parameter will be PFS rate at 1 year and it will be calculated in the ITT population. Analysis of secondary endpoints: Response to treatment will be described in a frequency table along with the corresponding percentages and 95% exact confidence intervals. Kaplan-Meier method will be used to estimate median PFS and overall survival (OS) values and 95% confidence intervals. All of these analyses will be performed in the ITT population. Analysis for objective response rate (ORR) will additionally be presented in the evaluable population for tumor response. Adverse Events (AEs) of the safety population for the FOLFIRI-aflibercept treatment part and the maintenance therapy will be presented in frequency tables according to grade, along with the corresponding percentages (N, %). Exploratory endpoints: Univariate and multivariate Cox regression analyses will also be performed to explore prognostic factors among basic clinicopathological characteristics and evaluated biomarkers, with respect to PFS and OS. Time-to-event distributions for the expression of examined markers will be estimated by Kaplan-Meier method and compared using log-rank test. Formalin-fixed embedded tumor tissue blocks will be collected from the primaries or metastases for the immunohistochemical and messenger ribonucleic acid (mRNA) study of key angiogenic effectors and regulators, such as: vascular endothelial growth factor A (VEGF A), vascular endothelial growth factor A-121 (VEGFA-121), vascular endothelial growth factor A121b (VEGFA121b), short and long VEGFA isoforms, metalloproteinase inhibitor 3 (TIMP3), vascular endothelial growth factor B (VEGF-B), placental growth factor (PlGF), vascular endothelial growth factor-C (AVEGF-C), Semaphorins, hypoxia-inducible factor 1 (HIF1), vascular endothelial growth factor receptor 1 (VEGFR1), vascular endothelial growth factor receptor 2 (VEGFR2), neuropilin 1 (NRP1), neuropilin 2 (NRP2), thrombospondin 1 (TSP1), thrombospondin 2 (TSP2), angiopoietin-1 (Ang1), Angiopoietin-2 (Ang2), Tie2, interleukin 8 (IL8), CXC chemokine receptor 1 (CXCR1), CXC chemokine receptor 2 (CXCR2) Pharmacokinetic(PK)/Pharmacodynamic analyses (PD) PK/PD assessments (plasma analytes, plasma free and VEGF-bound aflibercept) will be performed in all registered and treated patients at specified timepoints during both FOLFIRI-aflibercept induction and aflibercept maintenance therapy, to assess the free/bound aflibercept ratio over cycles and the potential correlation with clinical endpoints (safety and efficacy).