LCL161 in Treating Patients With Primary Myelofibrosis, Post-Polycythemia Vera Myelofibrosis, or Post-Essential Thrombocytosis Myelofibrosis

This phase II trial studies how well second mitochondrial-derived activator of caspases (SMAC) mimetic LCL161 (LCL161) works in treating patients with primary myelofibrosis, post-polycythemia vera myelofibrosis, or post-essential thrombocytosis myelofibrosis. SMAC mimetic LCL161 may help control the growth of abnormal cells by promoting apoptosis (programmed cell death).

PRIMARY OBJECTIVES: I. To determine the efficacy of LCL161 as therapy for primary myelofibrosis (PMF), post-polycythemia vera (PV) myelofibrosis (MF) and post-essential thrombocytosis (ET) MF. II. To determine the objective response which is defined as CR (complete remission) + PR (partial remission) + CI (clinical improvement) after three cycles of treatment. SECONDARY OBJECTIVES: I. To determine the safety of LCL161 as therapy for PMF, post-PV MF and post-ET MF. II. To determine time to response and response duration. III. To assess changes in symptom burden as assessed by Myeloproliferative Neoplasm Symptom Assessment Form Total Symptom Score (MPN-SAF TSS) and M.D. Anderson Symptom Inventory (MDASI) questionnaires. EXPLORATORY OBJECTIVE: I. To assess the mechanisms of action of LCL161 in patients with MF; these studies will include the analysis of baculoviral IAP repeat containing 2 (cIAP1), X-linked inhibitor of apoptosis, E3 ubiquitin protein ligase (XIAP), and poly (adenosine diphosphate \[ADP\]-ribose) polymerase 1 (PARP) protein levels which will be determined by western blot (actin as loading control) and will be measured at baseline and at beginning of each cycle for first 3 cycles and at end of study. OUTLINE: Patients receive SMAC mimetic LCL161 orally (PO) on days 1, 8, 15, and 22. Cycles repeat every 28 days in the absence of disease progression or unacceptable toxicity. After completion of study treatment, patients are followed up for 30 days.