Exploratory Phase II Study of INC424 Patients With Primary Myelofibrosis (PMF) or Post Polycythaemia Myelofibrosis (PPV MF) or Post Essential Thrombocythaemia Myelofibrosis (PET-MF)

Inclusion Criteria: * Patients must not be eligible for another ongoing INC424 clinical trial. * Patients must be diagnosed with PMF, PPV MF or PET-MF, according to the 2008 revised World Health Organization criteria irrespective of JAK2 mutation status. * Patients with PMF requiring therapy must be classified as high risk (3 prognostic factors) OR intermediate risk level 2 (2 prognostic factors, no more), OR intermediate risk level 1 (1 prognostic factor, no more) with an enlarged spleen. The prognostic factors, defined by the International Working Group are: 1. Age \> 65 years; 2. Presence of constitutional symptoms (weight loss, fever, night sweats); marked anemia (Hgb \< 10g/dL)\*; 3. Leukocytosis (history of WBC \> 25 x109/L); 4. Circulating blasts \> 1%. • A hemoglobin value \< 10 g/dL must be demonstrated during the Screening Visit for patients who are not transfusion dependent. Patients receiving regular transfusions of packed red blood cells will be considered to have hemoglobin \< 10 g/dL for the purpose of evaluation of risk factors. * Patients with Intermediate-1 disease and splenomegaly must have a palpable spleen measuring 5 cm or greater from the costal margin to the point of greatest splenic protrusion. * Patients must have a peripheral blood blast count of \< 10%. * Patients with adequate liver function defined as direct bilirubin ≤ 2.0 x ULN and ALT ≤ 2.5 x ULN. * Patients with adequate renal function defined as serum creatinine ≤ 2 x ULN. * Patients with an ECOG performance status of 0, 1, or 2 (Appendix 5). Exclusion criteria: * Patients eligible for hematopoietic stem cell transplantation (suitable candidate and a suitable donor is available). * Patients with history of malignancy in past 3 years except for treated, early-stage squamous or basal cell carcinoma in situ. * Patients undergoing treatment with hematopoietic growth factor receptor agonists (i.e., erythropoietin \[Epo\], granulocyte colony stimulating factor (GCSF \[Neupogen; Neulasta\], romiplostim, eltrombopag) at any time within 2 weeks prior to Screening or 4 weeks prior to Baseline. * Impairment of gastrointestinal (GI) function or GI disease that may significantly alter the absorption of oral INC424 (e.g., ulcerative diseases, uncontrolled nausea, vomiting, diarrhea, malabsorption syndrome, small bowel resection). * Patients with cardiac disease which in the Investigator's opinion may jeopardize the safety of the patient or the compliance with the protocol. * Patients with clinically significant bacterial, fungal, parasitic or viral infection which require therapy. Patients with acute bacterial infections requiring antibiotic use should delay screening/enrollment until the course of antibiotic therapy has been completed. * Patients with known active hepatitis A, B, C or who are HIV-positive. * Patients with inadequate bone marrow reserve as demonstrated by: 1. Absolute neutrophil count (ANC) that is ≤ 1000/µL. 2. Platelet count that is \< 100,000/µL without the assistance of growth factors, thrombopoietic factors or platelet transfusions. * Patients with any history of platelet counts \< 50,000/µL or ANC \< 500/µL except during treatment for a myeloproliferative disorder or treatment with cytotoxic therapy for any other reason. * Patients with coagulation parameters (PT, PTT, INR) ≥ 1.5. * Patients with known hypersensitivity to INC424 or other JAK1/2 inhibitors, or to their excipients. * Patients under ongoing treatment with another investigational medication or having been treated with an investigational medication within 30 days of screening. * Patients with any concurrent condition that, in the Investigator's opinion would jeopardize the safety of the patient or compliance with the protocol. Other protocol-defined inclusion/exclusion criteria may apply.