(BOREAS: This phase II trial is evaluating an oral drug (KRT-232) for the treatment of patients with myelofibrosis who are no longer benefiting their current treatment with a JAK inhibitorAn Open-Label, Phase 2a/2b Study of KRT-232 in Subjects With Primary Myelofibrosis (PMF), Post-Polycythemia Vera MF (Post-PV-MF), Or Post-Essential Thrombocythemia MF (Post-ET-MF) Who Have Failed a JAK Inhibitor

Exclusion

• Prior splenectomy
• Splenic irradiation within 3 months prior to randomization
• History of major hemorrhage or intracranial hemorrhage within 6 months prior to randomization
• History of stroke, reversible ischemic neurological defect or transient ischemic attack within 6 months prior to randomization
• Prior MDM2 inhibitor therapy or p53-directed therapy
• Prior allogeneic stem-cell transplant or plans for allogeneic stem cell transplant
• History of major organ transplant
• Grade 2 or higher QTc prolongation (> 480 milliseconds per NCI-CTCAE criteria, version 5.0)