Title: Toxicity and efficacy of FOLFIRI regimen and aflibercept combination in metastatic colorectal cancer: first results of a Russian multicenter retrospective study
Abstract: Purpose . To assess the incidence and severity of adverse events; to explore clinical factors associated with grade 3–4 non-hematologic toxicity; to assess the immediate efficacy and progression-free survival during treatment with the FOLFIRI regimen in combination with aflibercept in Russia. Materials and Methods . A retrospective multicenter study has been conducted with data collected from 20 clinics in 15 regions of Russia. There was no statistical hypothesis. Progression-free survival was the main efficacy criterion. The statistical analysis was performed using IBM SPPS Statistics v. 20 software. Results . FOLFIRI and Aflibercept combination was administered to 264 patients. The mean number of treatment cycles was 6 (1 to 29). The toxicity of aflibercept was addressed by dose reduction and dosing delay in 10.1 % and 11.4 % of patients, respectively, and dose reductions and dosing delays in any of FOLIFRI components were reported in 20.1 % of participants. The objective response rate was 20.3 %. The median progression-free survival in patients receiving second-line treatment was 6 months (95 % CI: 5.3–6.6 months). Seventy-two percent of patients experienced any grade of adverse events most of which were limited to grade 1–2 (62.1 %). Non-hematologic toxicity was reported in 64 % of patients (grade 3–4 in 17.9 %). Hematologic events were detected in only 17.9 % of patients. Multifactorial analysis has shown that drug therapy for concomitant diseases (OR 1.98, 95 % CI: 1.04–3.78, p = 0.037) and the number of chemotherapy lines prior to aflibercept (ОR 1.5, 95 % CI: 1.06–2.11, p = 0.02) were independent predictors of grade 3–4 non-hematologic toxicity. Conclusions . Objective response rate, progression-free survival, and frequency of toxicity-related aflibercept discontinuations in the Russian study with patients receiving aflibercept in combination with FOLFIRI regimen as a second-line treatment has shown the results that were comparable with VELOUR study. Comorbidities requiring drug treatment and the number of prior chemotherapy lines appear to be risk factors for grade 3–4 nonhematological toxicity events.