Study of Ruxolitinib (INCB018424) Sustained Release Formulation in Myelofibrosis Patients

An Open-label Assessment of Once-daily Dosing of a Sustained Release (SR) Formulation of INCB018424 in Patients With Primary Myelofibrosis, Post-essential Thrombocythemia Myelofibrosis, and Post-polycythemia Vera Myelofibrosis

The purpose of this study is to determine the safety and tolerability of ruxolitinib (INCB018424) sustained release (SR) formulation in participants with primary myelofibrosis (PMF), post-polycythemia vera MF (PPV-MF), and post-essential thrombocythemia MF (PET-MF).

The study will enroll approximately 40 participants with PMF, PPV-MF or PET-MF. Participants will take ruxolitinib SR once daily for 16 consecutive weeks and then transition to a comparable twice daily dose regimen of ruxolitinib using the immediate release (IR) tablets which have been under investigation in controlled Phase 1, 2, and 3 clinical trials.

Participants receiving benefit from treatment with ruxolitinib may continue further participation with IR tablets up to the time when the last participant completed Week 36 or the commercial availability of ruxolitinib IR, whichever was earlier. Follow-up will occur at least 30 days following the last dose of ruxolitinib.

Inclusion Criteria:

• Participants 18 years of age or older.
• Participants must be diagnosed with primary myelofibrosis (PMF), post-essential thrombocythemia myelofibrosis (PPV-MF), or post-polycythemia vera myelofibrosis (PET-MF).
• Participants with myelofibrosis requiring therapy must be classified as high risk (3 or more prognostic factors), intermediate risk level 2 (2 prognostic factors), or intermediate risk level 1 (1 prognostic factor)defined by International Working Group for Myelofibrosis Research and Treatment (IWG-MRT).
• Participants must have a palpable spleen measuring 5 cm or greater below the costal margin.

Exclusion Criteria:

• Participants with a life expectancy of less than 6 months.
• Participants of childbearing potential who are unwilling to take appropriate precautions to avoid pregnancy or fathering a child.
• Participants with inadequate bone marrow reserve.
• Participants with history of platelet counts < 50,000/μL, platelet transfusion(s), or an absolute neutrophil count < 500/μL in the month prior to Screening.
• Participants with inadequate liver or renal function at Screening and Baseline visits.