Study of Combination Ruxolitinib and Decitabine Treatment for Accelerated Phase MPN or Post-MPN AML

Overview

The purpose of this study is to test the safety and tolerability of ruxolitinib at different dose levels in combination with decitabine and the effectiveness of ruxolitinib in combination with decitabine in patients with accelerated or blast phase Myeloproliferative Neoplasm (MPN), which is a group of diseases of the bone marrow in which excess cells are produced. Ruxolitinib is a drug that is approved by the Federal Drug Administration (FDA) for the treatment of patients with advanced forms of myelofibrosis. It inhibits the Jak proteins that are often abnormal in MPN. A recent clinical study showed that ruxolitinib treatment could put some patients with this disease into remission. Decitabine is a chemotherapy, approved by the Federal Drug Administration (FDA), that has been used to treat acute leukemia. It works in some patients, but most patients with accelerated and blastic MPN do not respond to treatment. Ruxolitinib and decitabine will be combined in this study to find out what dose of the two medicines are safe together. Using Ruxolitinib in combination with Decitabine is experimental. The investigators want to find out what effects, good and/or bad it has on the patient and the disease.

At this time, there is no standard medical treatment for MF-BP or MF-AP. The investigators believe that the combination of ruxolitinib and DEC is a candidate approach to the treatment of MF-BP/MF-AP that is worthy of exploration based on both the current understanding of the biology of disease and emerging preclinical data. The molecular pathogenesis of MPN and progression to blast phase is almost certainly due to a complex combination of gene mutations (JAK2V617F, MPL) and epigenetic alterations (IDH1/2, IKZF1, EZH2, TET2) that culminate in the emergence of leukemic clones. Recent evidence indicates that the JAK2V617F protein can localize in the nucleus and influence global DNA methylation patterns which may lead to genomic instability and disease progression. The inhibition of JAK-STAT mediated cell proliferation and survival in conjunction with the reversal of DNA hypermethylation of tumor suppressor genes would be predicted to have at least an additive if not synergistic effect in inducing apoptosis of cells belonging to the malignant myeloid clone. Correlative studies conducted within a trial of Private and Confidential MPD-RC 109 Ruxolitinib + Decitabine combination JAK2 inhibitor and DMNT1 inhibitor in patients with MPN-BP would explore the effect on methylation status of various gene promoters as well as the influence on gene expression of chromatin related proteins and ultimately leukemic cell survival. The sequential administration of a JAK2 inhibitor followed by a DNMT inhibitor would also potentially serve to overcome the JAK2-independent effects of epigenetic lesions that lead to MPN-BP. In addition, a murine model of leukemic transformation has been described. In this model, bone marrow obtained from Tp53 null mice is retrovirally transduced with Jak2V617F, and transplanted into donor C56BL/6 mice. The transplanted mice develop an MPN which progresses to AML. In vitro drug studies utilizing bone marrow from these leukemic mice have demonstrated that exposure to decitabine or ruxolitinib inhibits colony formation in a methylcellulose colony-forming assay. Importantly, the combination of decitabine and ruxolitinib in this assay significantly reduces colony formation when compared to either drug alone (Rampal et al. ASH 2012 oral abstract 808) thus providing pre-clinical evidence for the combination study proposed here.