- To evaluate the efficacy of once daily dose of SAR302503 in subjects previously treated with ruxolitinib and with a current diagnosis of intermediate-1 with symptoms, Intermediate-2 or high-risk primary myelofibrosis (PMF), post-polycythemia vera myelofibrosis (Post-PV MF), or post-essential thrombocythemia myelofibrosis (Post-ET MF) based on the reduction of spleen volume at the end of 6 treatment cycles;