A Phase 1b Study of Pelabresib (DAK539) add-on to Stable Dose of Ruxolitinib in Japanese Adult Patients With Myelofibrosis
This Phase 1b, multicenter, open-label study aims to evaluate the safety, pharmacokinetics (PK), and preliminary efficacy of pelabresib as add-on to ruxolitinib in Japanese patients with myelofibrosis (MF).
• Participants have diagnosis of primary myelofibrosis (PMF), post-polycythemia vera MF (Post-PV MF) or post-essential thrombocythemia MF (Post-ET MF) according to the International Consensus Classification (ICC) for Myeloid Neoplasms and Acute Leukemias 2022.
• DIPSS risk category intermediate-1, intermediate-2 or high-risk at screening.
• Participants currently treated with ruxolitinib monotherapy AND who are likely to benefit from the addition of pelabresib to ruxolitinib in the opinion of the investigator.
• Receiving ruxolitinib at a stable dose (5 to 25 mg BID) for at least 8 weeks prior to the first dose of pelabresib.
• Palpable spleen (spleen length below left costal margin \[LCM\] must be recorded) or documented splenomegaly by MRI or CT (image report must be recorded) at screening.
• Platelet count ≥ 100 × 10\^9/L in the absence of growth factor support (including thrombopoietin mimetics/agonists) or platelet transfusions 4 weeks prior to the first dose of pelabresib.
• Blasts \< 5% in peripheral blood. Assessment of blasts in peripheral blood is mandatory at screening.