The study design is a non comparative randomized phase II trial: ARM 1: cabazitaxel (20 mg/m2, every 3 weeks) versus ARM 2 methotrexate (40 mg/m2, weekly). Cabazitaxel dose will be increased to 25mg/m2 for the second and subsequent cycles, in the absence of non-hematological AE > grade 2 and hematological AE > grade 3 during the first cycle. (maximum 10 cycles). The aim of the randomization is to offer a valid internal control group by avoiding possible selection bias. However, results obtained in the two treatment group will not be formally compared as this is not the objective of a phase II study.