0000000000300525
AUTHOR
Florian H. Heidel
Updated Results from the German Mpnsg-0212 Combination Trial: Ruxolitinib Plus Pomalidomide in Myelofibrosis with Anemia
Background: Anemia remains one cardinal symptom associated with reduced quality of life (QoL) in patients (pts) with myelofibrosis (MF) which is normally not being addressed by ruxolitinib (RUX). In our previous MPNSG-0109 trial, single-agent pomalidomide (POM) improved cytopenia in 14% (POM 0.5 mg QD) and 29% (POM 2.0 mg QD) of MF pts, respectively. In the MPNSG-0212 study, we sought to investigate the potential synergism of RUX plus POM to improve anemia and QoL in MF pts. Study Design: MPNSG-0212 is an ongoing multicenter, open-label, single-arm phase-Ib/II trial with a target population of 90 pts following a two-stage design (NCT01644110). Pts 1-40 in cohort 1 (co1) were treated with RU…
A neoepitope generated by an FLT3 internal tandem duplication (FLT3-ITD) is recognized by leukemia-reactive autologous CD8+ T cells.
Abstract The FLT3 receptor tyrosine kinase is expressed in more than 90% of acute myelogeneous leukemias (AMLs), up to 30% of which carry an internal tandem duplication (ITD) within the FLT3 gene. Although varying duplication sites exist, most FLT3-ITDs affect a single protein domain. We analyzed the FLT3-ITD of an AML patient for encoding HLA class I–restricted immunogenic peptides. One of the tested peptides (YVDFREYEYY) induced in vitro autologous T-cell responses restricted by HLA-A*0101 that were also detectable ex vivo. These peptide-reactive T cells recognized targets transfected with the patient's FLT3-ITD, but not wild-type FLT3, and recognized the patient's AML cells. Our results …
Genomic Landscape and Molecular Risk in Patients with Advanced Myelofibrosis Treated within the Multicenter Phase Ib/II MPNSG0212 (POMINC) Trial
Abstract Introduction: Mutations (muts) in JAK2, MPL, and CALR are genetic hallmarks in myeloproliferative neoplasms such as myelofibrosis (MF). Prognostication in MF is predominantly based on clinical parameters according to the Dynamic International Prognostic Scoring System (DIPSS). However, gene mutations become increasingly important allowing for a more precised assessment of prognosis. For instance, CALR mutated MF is associated with favorable prognosis, while mutations in distinct high molecular-risk (HMR) genes are considered adverse. Our multicenter phase-Ib/II MPNSG-0212 trial (NCT01644110) investigating ruxolitinib plus pomalidomide in a total cohort of 92 patients with advanced …
Bis(1H-indol-2-yl)methanones are effective inhibitors of FLT3-ITD tyrosine kinase and partially overcome resistance to PKC412A in vitro.
Inhibition of the mutated fms-like tyrosine kinase 3 (FLT3) receptor tyrosine kinase is a promising therapeutic strategy in acute myeloid leukaemia (AML). However, development of resistance to FLT3 tyrosine kinase inhibitors (TKI), such as PKC412A, has been described recently. This observation may have an increasing impact on the duration of response and relapse rates in upcoming clinical trials employing FLT3-TKI. Herein we investigated two representatives of a novel class of FLT3-TKI: Bis(1H-indol-2-yl)methanones. Both compounds effectively induced apoptosis in FLT3-internal tandem duplicate (ITD)-transfected murine myeloid cells and in primary FLT3-ITD positive blasts. Combination of bot…
Analysis of Differentially Activated Signaling Pathways in Myeloproliferative Disease Using Kinomics Chip Profiling
Abstract In a multitude of cases, oncogenic mutations are gain of function mutations that confer a constitutively activated gene product. Currently, evidence from a large body of experimental studies suggests that oncogenic transformation induced by activating kinase mutations is not sufficiently explained by constitutive kinase activation alone but is a result of aberrantly activated signaling pathways in affected cells. The JAK2V617F-mutation is a highly prevalent molecular marker in Ph-negative myeloproliferative disease (MPD). In vitro, Ba/F3-cells expressing both erythropoietin receptor (EpoR) and the JAK2V617F-mutation show constitutive activation of the JAK-STAT pathway and cytokine …
LS104, a non-ATP-competitive small-molecule inhibitor of JAK2, is potently inducing apoptosis in JAK2V617F-positive cells
Abstract The activating JAK2V617F mutation has been described in the majority of patients with BCR-ABL-negative myeloproliferative disorders (MPD). In this report, we characterize the small-molecule LS104 as a novel non-ATP-competitive JAK2 inhibitor: Treatment of JAK2V617F-positive cells with LS104 resulted in dose-dependent induction of apoptosis and inhibition of JAK2 autophosphorylation and of downstream targets. Activation of these targets by JAK2 was confirmed in experiments using small interfering RNA. LS104 inhibited JAK2 kinase activity in vitro. This effect was not reversible using elevated ATP concentrations, whereas variation of the kinase substrate peptide led to modulation of …
Clinical resistance to the kinase inhibitor PKC412 in acute myeloid leukemia by mutation of Asn-676 in the FLT3 tyrosine kinase domain.
Activating mutations in the FLT3 tyrosine kinase (TK) occur in approximately 35% of patients with acute myeloid leukemia (AML). Therefore, targeting mutated FLT3 is an attractive therapeutic strategy, and early clinical trials testing FLT3 TK inhibitors (TKI) showed measurable clinical responses. Most of these responses were transient; however, in a subset of patients blast recurrence was preceded by an interval of prolonged remission. The etiology of clinical resistance to FLT3-TKI in AML is unclear but is of major significance for the development of future therapeutic strategies. We searched for mechanisms of resistance in 6 patients with AML who had relapses upon PKC412 treatment. In an …
A phase 1b, dose-finding study of ruxolitinib plus panobinostat in patients with myelofibrosis.
7022^ Background: Myelofibrosis (MF) is a myeloproliferative neoplasm characterized by dysregulation of the Janus kinase (JAK) pathway resulting in bone marrow fibrosis, splenomegaly, and debilitat...
Efficacy, Safety, and Confirmation of the Recommended Phase 2 Starting Dose of the Combination of Ruxolitinib (RUX) and Panobinostat (PAN) in Patients (Pts) with Myelofibrosis (MF)
Abstract BACKGROUND: MF is a myeloproliferative neoplasm characterized by bone marrow (BM) fibrosis, splenomegaly, and debilitating constitutional symptoms. RUX is a potent JAK1/JAK2 inhibitor that has demonstrated superiority in spleen volume reduction, symptom improvement, and survival in the phase 3 COMFORT studies compared with placebo and best available therapy. PAN, a potent pan-deacetylase inhibitor, inhibits JAK signaling by disrupting the interaction between JAK2 and heat shock protein 90, a protein chaperone. PAN has demonstrated reductions in splenomegaly and improvement of BM fibrosis in phase 1/2 studies. The combination of RUX and PAN demonstrated synergistic activity in precl…
Efficacy, Safety, and Confirmation of the Recommended Phase 2 Dose of Ruxolitinib Plus Panobinostat in Patients with Intermediate or High-Risk Myelofibrosis
Abstract Background: Myelofibrosis (MF) is a clonal neoplastic disease resulting in bone marrow fibrosis, splenomegaly, and debilitating constitutional symptoms. The Janus kinase (JAK) pathway is often dysregulated in MF, and agents targeting this pathway have demonstrated efficacy in this disease. Ruxolitinib (RUX), a potent JAK1/JAK2 inhibitor, demonstrated superiority in spleen volume reduction, symptom improvement, and survival compared with the control arm in the phase III COMFORT-I and COMFORT-II studies. Panobinostat (PAN), a potent pan-deacetylase inhibitor (pan-DACi), inhibits JAK signaling through disruption of the interaction of JAK2 with the protein chaperone heat shock protein …
Ruxolitinib Plus Pomalidomide in Myelofibrosis: Updated Results from the Mpnsg-0212 Trial (NCT01644110)
Abstract Background: Although ruxolitinib (RUX) reduces constitutional symptoms and splenomegaly in myelofibrosis (MF) therapy options for anemia are limited. In our prior MPNSG-0109 trial of pomalidomide (POM) in MF with cytopenia, anemia responses were reported in 14% and 29% of subjects receiving POM 0.5 mg/d and 2 mg/d, respectively (Schlenk RF et al., ASH 2013, abstract #2822). We designed a phase-Ib/-II combination study of RUX plus POM to evaluate synergistic effects in subjects with anemia and splenomegaly (MPNSG-0212 trial, NCT01644110; Stegelmann et al., ASH 2015, abstract #826). Study Design: Primary endpoints are response rate after 12 treatment cycles (28 days each) according t…
Different FLT3-ITD Integration Sites Are Associated with Differential Sensitivity to Tyrosine Kinase Inhibitors (TKI) In Vitro.
Abstract Abstract 1709 Introduction: Currently, small molecule FLT3 tyrosine kinase inhibitors (TKIs) are promising therapeutic approaches to overcome the dismal prognosis of AML patients harbouring FLT3-ITD mutations. However, up to 30% of these patients show primary resistance to FLT3-TKIs. Recently, we uncovered a novel mechanism of primary resistance to FLT3 TKIs in a patient displaying an atypical integration site of ITD within the beta2-sheet (ITD_A627E). The data suggested that atypical integration sites of ITDs within the tyrosine kinase domain-1 (TKD1) of FLT3 (beta1-sheet, nucleotide binding loop and beta2-sheet) are associated with rewired signaling and differential responsivenes…