Phase II, Open Label, Single Arm Study of SAR302503 In Myelofibrosis Patients Previously Treated With Ruxolitinib

Inclusion criteria: * Diagnosis of PMF or Post-PV MF or Post-ET MF, according to the 2008 World Health Organization and IWG-MRT response criteria * Subjects who previously received Ruxolitinib treatment for PMF or Post-PV MF or Post-ET MF or PV or ET for at least 14 days (exposure of \<14 days is allowed for subjects who discontinued Ruxolitinib due to intolerability or allergy) and discontinued the treatment for at least 14 days prior to the first dose of SAR302503 * MF classified as Intermediate-1 with symptoms, Intermediate-2 or high-risk by Dynamic International Prognostic Scoring System (Passamonti et al., Blood 2010) * Spleen ≥5 cm below costal margin as measured by palpation * Male and female subjects ≥18 years of age * Signed written informed consent Exclusion criteria: * Splenectomy * Eastern Cooperative Oncology Group (ECOG) performance status of \>2 before the first dose of SAR302503 at Cycle 1 Day1 * The following laboratory values within 14 days prior to the initiation of SAR302503: * Absolute Neutrophil Count (ANC) \<1.0 x 10exp9/L * Platelet count \<50 x 10exp9/L * Serum creatinine \>1.5 x Upper limit of normal (ULN) * Serum amylase and lipase \>1.5 x ULN * Aspartate aminotransferase (AST) or alanine aminotransferase (ALT) ≥2.5 x ULN * Total bilirubin ≥3.0 x ULN * Subjects with total bilirubin between 1.5-3.0 x ULN must be excluded if the direct bilirubin fraction is ≥25% of the total * Subjects with known active (acute or chronic) Hepatitis A, B, o…