Updated results, multivariate and subgroups analysis confirm improved activity and efficacy for FOLFOXIRI versus FOLFIRI in the G.O.N.O. randomized phase III study in metastatic colorectal cancer (MCRC)

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4026 Background: As previously reported (ASCO 2006) the G.O.N.O. conduced a phase III study comparing FOLFIRI to FOLFOXIRI in 244 patients (pts) with not resectable MCRC. At a median follow-up of 18.4 months (mos) we reported significant improvements in response-rate (RR), R0 resection of metastases (mts), PFS and OS for FOLFOXIRI. Methods: Results have been updated (median follow-up of 36.2 mos) and 14 variables were tested as possible prognostic factors for response, R0 resection, PFS and OS. Results: At this updated analysis 225 (111 vs 114) pts have progressed and 180 (84 vs 96) have died. Results confirm the significant improvements for FOLFOXIRI in terms of confirmed RR (60% vs 34% p<0.001), R0 resection of residual mts (15% vs 6% p=0.033 and 36% vs 12% p=0.017 for pts with liver only mts), PFS (median 9.8 vs 6.9 mos p<0.001) and OS (median 23.6 vs 16.7 mos p=0.042) at the cost of a modest and acceptable increase in toxicity. In the logistic regression multivariate analysis treatment with FOLFOXIRI was the only independent predictive factor for response (HR:2.9, p<0.001) and for achieving an R0 surgical resection of mts (HR:3.1, p=0.018). The Cox’s multivariate analysis demonstrates that independent prognostic factors for improved time to progression were treatment with FOLFOXIRI (HR:0.64, p<0.001), and ECOG PS = 0 (HR:0.73, p=0.02) and for time to death were treatment with FOLFOXIRI (HR:0.74, p=0.04) and liver involvement <25% (HR:0.57, p=0.006). The benefits of FOLFOXIRI was consistent across all subgroups, including those with unfavorable prognosis such as pts with time from diagnosis to randomization <3 mos, multiple site of disease or liver involvement ≥ 25%. Conclusions: FOLFOXIRI confirms to be the first combination demonstrated to be superior to an infusional 5FU containing doublet as FOLFIRI in terms of RR, R0 resections, PFS and OS. FOLFOXIRI represents a new treatment option in MCRC and its use and study is of particular interest in a neoadjuvant strategy, in pts with few chances to achieve a three-drug exposure in a sequential strategy and in combination with targeted agents. Partially supported by Fondazione ARCO. No significant financial relationships to disclose.