Phase III study to compare two different chemotherapy treatments to determine whether the first line with the three drugs + bevacizumab followed by a second line with the same regimen may provide better results than treatment with two drugs + bevacizumab is the first and the second treatment line

Primary objectives: The main objective of this trial is to compare the efficacy of the two proposed treatment strategies in terms of duration of Progression Free Survival 2 (PFS2).
Primary endpoints: The primary endpoint is Progression Free Survival 2 (PFS2).PFS2 will be defined as beginning with randomization and ending with the first of the following events: a) death; b) disease progression on any treatment given after 1st progression. For patients that will not receive any treatment within 3 months after 1st progression, PFS2 will be equal to PFS. The determination of disease progression will be based on investigator-reported measurements. Disease status will be evaluated according to RECIST 1.1 criteria.Censoring rules for PFS2 will be: end of study without PD, loss at follow-up. Curative surgery for metastasis will not result in censoring for PFS2.PFS2 will be analyzed both in the intention-to-treat population (primary analysis) and in the per-protocol population.