Treatment-Emergent AEs are events occurring after first drug administration or worsened from baseline.

Treatment-Related AEs are those with a definite, probable, possible or missing causality.

A serious AE is a medical occurrence that results in death, is life-threatening, requires inpatient hospitalization or prolongation of hospitalization, results in persistent or significant disability/incapacity, is a congenital anomaly/birth defect or is a medical event requiring intervention to prevent 1 of the above.

A severe or life-threatening AE is based on intensity, according to National Cancer Institute-Common Toxicity Criteria for Adverse Effects (NCI-CTCAE) v3.0.

Safety population included all patients who received at least 1 dose of study medication.

Clinical improvement was defined according to the International Working Group Myelofibrosis Research and Treatment criteria, and required 1 of the following:

1. A ≥ 2 g/dL increase in Hemoglobin level or becoming transfusion independent;
2. Either a ≥ 50% reduction in palpable splenomegaly if spleen was ≥ 10 cm at Baseline or a spleen palpable at > 5 cm at Baseline becomes not palpable;
3. A ≥ 100% increase in platelet count and an absolute platelet count of ≥ 50,000 x 10^9/L or
4. A ≥ 100% increase in absolute neutrophil count (ANC) and an ANC of ≥ 0.5 x 10^9/L.

The intent-to-treat population included all patients who received at least 1 dose of study medication and had at least 1 follow-up assessment for safety and efficacy. N = the number of patients who had clinical response assessed during the time interval.

For each visit, patients who had a missing value at the visit, dropped out of the study due to any reasons prior to the visit or had non-palpable spleen at baseline and then became palpable at the time of the visit were all considered as having not achieved the ≥ 50% reduction in spleen palpation length.

Intent to treat population. A total of 16 patients had either a splenectomy prior to study entry, missing Baseline spleen values or had spleen lengths reported as 0 cm and were excluded.

Spleen volume was assessed in a subgroup of 27 patients using magnetic resonance imaging (MRI) scans (or computed tomography (CT) scans in patients who were not candidates for MRI) of the abdomen in order to allow objective measurement of spleen volume using standard estimation techniques.

For each visit, patients who had a missing value at the visit or dropped out of the study due to any reason prior to the visit were considered as not having achieved the ≥35% reduction in spleen volume.

Patients with at least 1 Spleen-Volume Measurement. Patients who had not reached the visit were excluded from the analysis. In addition, at Week 48, 5 patients who did not have MRI measurement due to a protocol amendment were considered as not evaluable and were excluded from the analysis.

Symptoms of myelofibrosis were assessed using a modified Myelofibrosis Symptom Assessment Form (MFSAF). Abdominal discomfort, itching, muscle or bone pain, and night sweats are prominent and troubling symptoms in patients with MF. Therefore, the MFSAF-derived responses for these symptoms were analyzed as a total symptom score. Each symptom was assessed on a scale from 0 (absent), 1 (most favorable) to 10 (worst). The total symptom score is a sum of the individual scores and ranges from 0-40. A higher score indicates worse symptoms hence a negative change from baseline indicates improvement.

Intent-to-treat population for whom data was available. The MFSAF was implemented by protocol amendment while the study was ongoing. Hence data are available for only approximately 50% of enrolled patients. This analysis includes patients with a Baseline total symptom score ≥ 0; 8 patients were excluded because they had a Baseline score = 0.

Health-related Quality of Life was assessed using the Global Health Status/Quality of Life Scale of the European Organization for the Research and Treatment of Cancer Quality of Life Questionnaire (EORTC QLQ-C30). This scale ranges from 0 to 100, with higher scores indicating higher quality of life.

The safety population included all subjects who received at least 1 dose of study medication, and for whom data was available at both time points. The EORTC QLQ C30 was implemented by protocol amendment and as a result this data are available for only approximately 50% of the enrolled patients.

Intent-to-treat population for patients who had reached each time point and for whom data was available.

The ECOG performance status measures patients' functional status on the following scale:

• 0=Fully active, no restrictions;
• 1=Restricted in physically strenuous activity but ambulatory, able to carry out light work;
• 2=Ambulatory and capable of all selfcare, unable to carry out any work activities; Up and about > 50% of waking hours;
• 3=Limited selfcare, confined to bed or chair more than 50% of waking hours;
• 4=Completely disabled. Totally confined to bed or chair;
• 5=Dead.

Data reported indicate the number of participants with a change from Baseline score of -2, -1, 0 and 1.

Intent-to-treat population for patients who had reached each time point and for whom data was available.