Post-polycythemia Myelofibrosis Research Articles

CCN2/CTGF expression does not correlate with fibrosis in myeloproliferative neoplasms, consistent with noncanonical TGF-β signaling driving myelofibrosis

The classical BCR::ABL1-negative myeloproliferative neoplasms (MPN) form a group of bone marrow (BM) diseases with the potential to progress to acute myeloid leukemia or develop marrow fibrosis and subsequent BM failure. The mechanism by which BM fibrosis develops and the factors that drive stromal activation and fibrosis are not well understood. Cellular Communication Network 2 (CCN2), also known as CTGF (Connective Tissue Growth Factor), is a profibrotic matricellular protein functioning as an important driver and biomarker of fibrosis in a wide range of diseases outside the marrow. CCN2 can promote fibrosis directly or by acting as a factor downstream of TGF-β, the latter already known to contribute to myelofibrosis in MPN.To study the possible involvement of CCN2 in BM fibrosis in MPN, we assessed CCN2 protein expression by immunohistochemistry in 75 BM biopsies (55 × MPN and 20 × normal controls). We found variable expression of CCN2 in megakaryocytes with significant overexpression in a subgroup of 7 (13%) MPN cases; 4 of them (3 × essential thrombocytemia and 1 × prefibrotic primary myelofibrosis) showed no fibrosis (MF-0), 2 (1 × post-polycythemic myelofibrosis and 1 × primary myelofibrosis) showed moderate fibrosis (MF-2), and 1 (primary myelofibrosis) severe fibrosis (MF-3). Remarkably, CCN2 expression did not correlate with fibrosis or other disease parameters such as platelet count or thrombovascular events, neither in this subgroup nor in the whole study group. This suggests that in BM of MPN patients other, CCN2-independent pathways (such as noncanonical TGF-β signaling) may be more important for the development of fibrosis.

Approaches to the Treatment of Patients with Myelofibrosis and Polycythemia Vera with Constitutional Symptoms in Real-World Clinical Practice in the Russian Federation: Intermediate Results of a Multi-Center Observational Prospective Clinical Study

Aim. To describe the methods of drug therapy implemented for the disease control in patients with polycythemia vera (PV) and myelofibrosis (MF) as well as to analyze manifestations and severity of the disease symptoms in real-world clinical practice.
 Materials & Methods. The analysis focused on the data of 1229 patients. In 629 (51.18 %) patients, PV was diagnosed, MF was identified in 521 (42.39 %) patients. The diagnosis of 79 (6.43 %) patients was not reported. Early stage of primary MF (PMF) was detected in 182 (34.93 %) patients, PMF fibrosis stage was identified in 251 (48.18 %) patients, post-polycythemic MF was registered in 61 (11.71 %) patients, and 13 (2.5 %) patients showed post-thrombocythemic MF. In 14 (2.69 %) patients, MF type was not reported. By the time of diagnosis, the median age of PV patients was 56 years (range 17–86 years), and that of MF patients was 55 years (range 16–83 years) (p = 0.022). The proportion of women among PV patients was 57 %, among MF patients it was 65 % (p = 0.0065).
 Results. The assessment of thrombotic complication risk in PV showed that 51.01 % (n = 302) of patients belong to the low-risk, 39.86 % (n = 236) belong to the intermediate-risk, and only 9.12 % (n = 54) of patients belong to the high-risk groups. Distribution of MF patients between risk groups demonstrates favorable prognosis for most patients. The group of low and intermediate-1 risks includes 56.43 % (n = 294) patients according to the prognostic scoring system IPSS and 68.52 % (n = 357) according to the prognostic scoring system DIPSS. In the vast majority of cases, patients received hydroxycarbamide therapy: 81.81 % (n = 832) in the total cohort, 83.33 % (n = 465) in the PV group, and 79.96 % (n = 367) in the MF group. Interferon-α was administered to 19.71 % (n = 110) of PV patients and 29.85 % (n = 137) of MF patients. Ruxolitinib was assigned to 3.14 % (n = 19) of PV patients and 21.35 % (n = 98) of MF patients.
 Conclusion. Regular monitoring of the PV and MF course and treatment efficacy can provide recommendations for adequate change of therapy in case of the failure of previous treatment. It should be emphasized that the timely switch to the second-line therapy results in reduced disability and mortality among PV and MF patients with myeloproliferative neoplasms.

Role of Next Generation Immune Checkpoint Inhibitor (ICI) Therapy in Philadelphia Negative Classic Myeloproliferative Neoplasm (MPN): Review of the Literature.

The Philadelphia chromosome-negative (Ph-) myeloproliferative neoplasms (MPNs), which include essential thrombocythemia (ET), polycythemia vera (PV), and myelofibrosis (MF), are enduring and well-known conditions. These disorders are characterized by the abnormal growth of one or more hematopoietic cell lineages in the body's stem cells, leading to the enlargement of organs and the manifestation of constitutional symptoms. Numerous studies have provided evidence indicating that the pathogenesis of these diseases involves the dysregulation of the immune system and the presence of chronic inflammation, both of which are significant factors. Lately, the treatment of cancer including hematological malignancy has progressed on the agents aiming for the immune system, cytokine environment, immunotherapy agents, and targeted immune therapy. Immune checkpoints are the molecules that regulate T cell function in the tumor microenvironment (TME). The first line of primary immune checkpoints are programmed cell death-1 (PD-1)/programmed cell death ligand-1 (PD-L1), and cytotoxic T-lymphocyte antigen-4 (CTLA-4). Immune checkpoint inhibitor therapy (ICIT) exerts its anti-tumor actions by blocking the inhibitory pathways in T cells and has reformed cancer treatment. Despite the impressive clinical success of ICIT, tumor internal resistance poses a challenge for oncologists leading to a low response rate in solid tumors and hematological malignancies. A Phase II trial on nivolumab for patients with post-essential thrombocythemia myelofibrosis, primary myelofibrosis, or post-polycythemia myelofibrosis was performed (Identifier: NCT02421354). This trial tested the efficacy of a PD-1 blockade agent, namely nivolumab, but was terminated prematurely due to adverse events and lack of efficacy. A multicenter, Phase II, single-arm open-label study was conducted including pembrolizumab in patients with primary thrombocythemia, post-essential thrombocythemia or post-polycythemia vera myelofibrosis that were ineligible for or were previously treated with ruxolitinib. This study showed that pembrolizumab treatment did not have many adverse events, but there were no pertinent clinical responses hence it was terminated after the first stage was completed. To avail the benefits from immunotherapy, the paradigm has shifted to new immune checkpoints in the TME such as lymphocyte activation gene-3 (LAG-3), T cell immunoglobulin and mucin domain 3 (TIM-3), T cell immunoglobulin and ITIM domain (TIGIT), V-domain immunoglobulin-containing suppressor of T cell activation (VISTA), and human endogenous retrovirus-H long terminal repeat-associating protein 2 (HHLA2) forming the basis of next-generation ICIT. The primary aim of this article is to underscore and elucidate the significance of next-generation ICIT in the context of MPN. Specifically, we aim to explore the potential of monoclonal antibodies as targeted immunotherapy and the development of vaccines targeting specific MPN epitopes, with the intent of augmenting tumor-related immune responses. It is anticipated that these therapeutic modalities rooted in immunotherapy will not only expand but also enhance the existing treatment regimens for patients afflicted with MPN. Preliminary studies from our laboratory showed over-expressed MDSC and over-expressed VISTA in MDSC, and in progenitor and immune cells directing the need for more clinical trials using next-generation ICI in the treatment of MPN.

Splenomegaly (SPML) in polycythemia vera (PV): its clinical significance and its relation to symptoms, post-polycythemic myelofibrosis (PPMF) and survival.

Splenomegaly (SPML) in polycythemia vera (PV): its clinical significance and its relation to symptoms, post-polycythemic myelofibrosis (PPMF) and survival.

Possibilities of targeted therapy for myelofibrosis: Moscow experience

Background. For many years the primary aim of treatment strategy for ph-negative myeloproliferative neoplasms has been to restrain disease progression, with lasting relief and management of symptoms to improve patients’ quality of life. Generally, this did not lead to a significant increase in life expectancy with primary myelofibrosis and didn’t decrease the risk of fibrosis in patients with polycythemia vera and essential thrombocythemia. To date a new class of targeted drugs has been developed, it is JAK2 inhibitors with pathogenetic effects. The results of clinical trials showed the high efficacy of the first registered drug of this its kind – ruxolitinib – that includes a faster reduction in the symptoms of tumor intoxication and in symptoms associated with the development of splenomegaly and increase in the overall survival rates. It is known that the data obtained during clinical trials of medicines may differ from the results obtained in routine clinical practice. In actual practice drugs are used in a much wider heterogeneous population of patients, less limited first of all by age and comorbid characteristics. It is possible to analyze cohorts of patients including a larger number of clinical cases with a longer follow-up period. In this regard of great interest is the actual clinical experience of long-term use of ruxolitinib in patients whose set is limited only by clinical contraindications for prescribing the drug.Aim. To present our own actual experience of targeted therapy of myelofibrosis and compare the results obtained with the data of clinical trials.Materials and methods. Our analysis includes data from 141 patients (67 (47.5 %) men and 74 (52.5 %) women) in a chronic phase myelofibrosis. All patients received ruxolitinib. Of these, 109 (69 %) patients had primary myelofibrosis, 26 (16 %) – postpolycythemia myelofibrosis, 6 (4 %) – postessential thrombocythemia myelofibrosis. The median age at the start of therapy was 62 (18–84) years. The median disease duration before ruxolitinib was prescribed – 79 (1–401) months. According to the dIpSS (dynamic International prognostic Scoring System) criteria, 13 % of patients were assigned to the low risk group, 38 % – to the intermediate-1, 36 % – to the intermediate-2, 13 % – to the high risk group. Most patients (52 %) had grade 3 bone marrow fibrosis.Results. The median duration of treatment was 18 (range from 1 to 115) months. Symptoms of intoxication were relieved 74 (81 %) of 91 patients, the spleen size decreased in 81 % of patients (the spleen size returned to normal in 25 % of patients). The increase in the median hemoglobin level was 15 %. The proportion of patients requiring blood transfusion decreased by 4 times (from 39 to 9 %). Mean platelet levels normalized in most patients with baseline high and low platelet levels. A complete clinical and hematological response was achieved in 16 % (n = 23) of cases, a partial response – in 26 % (n = 37) of cases, clinical improvement – in 21 % (n = 30), disease stabilization – in 33 % (n = 46) of cases. No response was received in 1 (1 %) patient and in 3 (3 %) cases there was progression of the disease. At the time of analysis, 81 (57 %) of 141 patients were continuing the ruxolitinib treatment. The fatal outcome in 33 (22 %) patients was associated with concomitant diseases, among which 20 (14 %) died from proven COvId-19 infection. Overall survival: 1-year 81 %, 2-year 73 %, 5-year 50 %. Overall survival excluding deaths due to COvId-19: 1-year 92 %, 2-year 85 %, 5-year 70 %. Massive splenomegaly and a high degree of fibrosis were unfavorable predictors of prognosis of overall survival.Conclusion. Target therapy with Janus kinase inhibitor ruxolitinib has demonstrated high efficacy in patients with myelofibrosis in routine clinical practice. The most rapid effect ruxolitinib had on the spleen size and the symptoms of intoxication. Tolerability of ruxolitinib therapy was generally satisfactory. The overall and progression-free survival rates in patients with myelofibrosis, receiving ruxolitinib in the clinical setting was consistent with the results of international multicenter clinical trials.

Splenomegaly (SPML) in Polycythemia Vera (PV): Its Clinical Significance and its Relation to Symptoms, Post-Polycythemic Myelofibrosis (PPMF), and Survival

Splenomegaly (SPML) in Polycythemia Vera (PV): Its Clinical Significance and its Relation to Symptoms, Post-Polycythemic Myelofibrosis (PPMF), and Survival

A Pooled Overall Survival Analysis of The COMFORT Studies: 2 Randomized Phase 3 Trials of Ruxolitinib For The Treatment of Myelofibrosis

A Pooled Overall Survival Analysis of The COMFORT Studies: 2 Randomized Phase 3 Trials of Ruxolitinib For The Treatment of Myelofibrosis

СОВРЕМЕННАЯ ТЕРАПИЯ ПАЦИЕНТОВ С ПЕРВИЧНЫМ И ПОСТ-ПОЛИЦИТЕМИЧЕСКИМ МИЕЛОФИБРОЗОМ

Ph-negative myeloproliferative neoplasm are the group of hematologic disorders which includes primary myelofibrosis, polycythemia vera, essential trombocytemia and several rare diseases. After the discovery of V617 Fgain-of-function mutation the new period of diagnostics, treatment and evaluating of MPN prognosis began. At the current moment several molecules inhibiting JAK2 function are developed. Advanced therapy in patients with primary and post-polycythemic myelofibrosis included molecules inhibiting JAK2 function resulted in rapid and durable improvements in splenomegaly and disease-related symptoms in the phase 3 trials COMFORT-I and COMFORT-II. The effectiveness of the advanced therapy included molecule inhibiting JAK2 was evaluated in three patients with primary myelofibrosis and post-polycitemic myelofibrosis. All represented clinical cases demonstrated positive dynamics of the disease manifested in spleen size reduction, improvement of the symptoms and in one case in reduction of blood transfusions. None of three patients met serious adverse events leading to dose reduction or discontinuation of the molecule inhibiting JAK2. Target agents therapy demonstrated high treatment rates in patients with primary and post-polycythemic myelofibrosis. Thus, it is clearly necessary to perform molecular diagnosis, screening tests at early stages of the chronic myeloproliferative disease for the selection of patients in need for specific treatment.

Characteristics and clinical significance of cytogenetic abnormalities in polycythemia vera.

Up to 20% of patients with polycythemia vera have karyotypic abnormalities at the time of the initial diagnosis. However, the cytogenetic abnormalities in polycythemia vera have not been well characterized and their prognostic impact is largely unknown. In this study, we aimed to address these issues using a large cohort of polycythemia vera patients with cytogenetic information available. The study included 422 patients, 271 in polycythemic phase, 112 with post-polycythemic myelofibrosis, 11 in accelerated phase, and 28 in blast phase. Abnormal karyotypes were detected in 139 (33%) patients, ranging from 20% in those in the polycythemic phase to 90% among patients in accelerated/blast phase. Different phases harbored different abnormalities: isolated del(20q), +8 and +9 were the most common abnormalities in the polycythemic phase; del(20q) and +1q were the most common abnormalities in post-polycythemic myelofibrosis; and complex karyotypes were the most common karyotypes in accelerated and blast phases. Patients with an abnormal karyotype showed a higher frequency of disease progression, a shorter transformation-free survival and an inferior overall survival compared with patients with a normal karyotype in the same disease phase. Cytogenetics could be effectively stratified into three risk groups, low- (normal karyotype, sole +8, +9 and other single abnormality), intermediate- (sole del20q, +1q and other two abnormalities), and high-risk (complex karyotype) groups. We conclude that cytogenetic changes in polycythemia vera vary in different phases of disease, and carry different prognostic impacts.

Targeted Therapy of Myelofibrosis

Background. Myelofibrosis (primary myelofibrosis, postessential trombocythemia myelofibrosis, post-polycythemia myelofibrosis) is the most complex and pressing problem among all Ph-negative myeloproliferative diseases. The present article summarizes the author's experience of using new Janus kinase inhibitors in routine clinical practice, and compares the data with the results of other clinical research. Aim. To evaluate the use of ruxolitinib in patients with myelofibrosis. Materials & Methods. Our analysis includes 48 patients (21 men and 27 women) with histologically verified myelofibrosis (primary myelofibrosis in 36 cases, post-essential trombocythemia myelofibrosis in 10 cases, and post-polycythemia myelofibrosis in 2 cases) in a chronic stage. All patients received ruxolitinib. Median age at the start of therapy was 60 years (range from 35 to 79). Massive splenomegaly (> 10 cm below the costal margin) was found in 34 (71 %) of 48 patients. The initial dose of ruxolitinib was determined by the platelet level. The efficacy of the therapy was evaluated in accordance with ELN 2013 criteria. Results. Median duration of treatment was 18 months (range from 1 to 50 months). Symptoms of intoxication were relieved in 33 of 37 patients (89 %). The spleen size decreased in 64 % of patients. In 33 % of cases spleen size did not change, whereas an increase was observed in 3 % of patients. In the majority of patients hemoglobin level remained stable through the course of treatment. Three of 14 transfusion dependent patients did not require blood transfusions after 3 months of therapy. In patients with high thrombocyte levels prior to ruxolitinib therapy the mean level was approaching normal by the end of the 1st month of treatment. The median JAK2V617F mutant allele burden at the beginning treatment was 56.5 % (n = 20; 22.5-126.1 %). After 6 moths of treatment it accounted for 62.3 % (n = 11; 25.4-79.7 %) and in 12 months accounted for 47.4 % (n = 12; 14.2-102.2 %). By the time of the analysis 42 of 48 patients continued the ruxolitinib treatment (88 %). Death occurred in 4 patients. Overall 1-year (92 %) and 2-year (87 %) survival corresponds to the data of COMFORT-I, COMFORT-II and JUMP clinical trials. Conclusion. Ruxolitinib showed to be an effective treatment for myelofibrosis. The most pronounced and rapid effect ruxolitinib had on the spleen size and the symptoms of intoxication. The tolerability of ruxolitinib was satisfactory in the majority of patients. According to the author's data, ruxolitinib had a small impact on the JAK2V617F mutant allele burden. The overall survival rate in patients with myelofibrosis, receiving ruxolitinib in the clinical setting was similar to that of in the clinical trials.

Neutrophilic leukocytosis in advanced stage polycythemia vera: hematopathologic features and prognostic implications

Polycythemia vera in 20–30% of cases progresses towards post-polycythemic myelofibrosis, an advanced phase characterized by decreased red blood cells counts and increasing splenomegaly with extramedullary hematopoiesis. There is evidence that the presence of neutrophilic leukocytosis at polycythemia vera disease outset is associated with an increased risk of recurrent thrombosis. However, its clinical significance when developing later in the course of the disease is not well defined. Over a period of 8 years we identified from the files of two reference centers 10 patients (7M/3F, median age: 68 years) who developed persistent absolute leukocytosis ≥13 × 109/l (median: 25.1 × 109/l; range: 16.1–89.7 × 109/l) at or around the time of diagnosis of post-polycythemic myelofibrosis (median interval from diagnosis:0 months; range: −6/31) and persisted for a median period of 13 months. Peripheral blood smears showed numerous neutrophils without dysplastic features and, in four, ≥10% immature myeloid precursors. In five cases, corresponding marrow specimens obtained at or immediately after the onset of leukocytosis showed a markedly increased myeloid:erythroid ratio due to granulocytic proliferation. No change in JAK2 and BCR-ABL1 status or cytogenetic evolution was associated with the development of leukocytosis. The mutational status of CSF3R, SETBP1, and SRSF2, genes associated with other chronic myeloid neoplasms where neutrophilic leukocytosis occurs, was investigated but all cases showed wild-type only alleles. Four patients died after developing leukocytosis and one experienced worsening disease. Compared with a control group of post-polycythemic myelofibrosis patients (n=23) who never developed persistent leukocytosis, patients with leukocytosis showed higher white blood cells counts and a shorter overall survival. This is the first study describing the development of significant neutrophilic leukocytosis during advanced stages of polycythemia vera; it includes comprehensive hematologic, marrow morphological, molecular, and clinical data. Our findings suggest that persistent leukocytosis occurring at or around the time of progression to post-polycythemic myelofibrosis is associated with an overall more aggressive course of the disease.

Jumping Translocations in Myeloid Malignancies Associated With Treatment Resistance and Poor Survival.

Jumping translocations (JT) are uncommon cytogenetic abnormalities involving nonreciprocal translocations of a single donor chromosome onto 2 or more chromosomes. The clinical characteristics and prognosis of JTs in patients with myeloid malignancies are not well described. We searched our cytogenetic database from 2003 to 2014 to identify cases of myeloid malignancies associated with a JT. These cases were cross-referenced with our clinical databases to determine patient characteristics, response to treatment and overall survival. We identified 10 patients with myeloid malignancies and a JT: 4 cases of acute myeloid leukemia with myelodysplastic syndrome-related changes, 4 cases of myelodysplastic syndrome, and 2 cases of postpolycythemia myelofibrosis. The donor segment was derived from chromosome 1 in every case. The acquisition of a JT was a late occurrence, with a median time to JT development of 24.9 months (range, 0-248 months) from diagnosis. The overall response to treatment was poor, with no patients experiencing a response to conventional chemotherapy or hypomethylating agents. The median overall survival for the group was 9 months (95% confidence interval, 2.5-15.5) after identification of a JT. The acquisition of a JT in patients with myeloid malignancies appears to be a late event and is associated with myelodysplasia. In our series, this was associated with a poor prognosis with a poor response to treatment, disease transformation to acute myeloid leukemia, and short overall survival.

Imatinib and ruxolitinib association: first experience in two patients

We report the first case of 2 patients with a previous diagnosis of post-polycythemic (PV) myelofibrosis who developed chronic myeloid leukemia (CML) seven years later, both treated with an association of a tyrosine-kinase inhibitor (imatinib) and a JAK1/JAK2 inhibitor (ruxolitinib). In 1992, a 46-

Morphologic and cytogenetic differences between post-polycythemic myelofibrosis and primary myelofibrosis in fibrotic stage

Polycythemia vera and primary myelofibrosis share a propensity to progress toward a myelofibrotic late stage with overlapping clinical characteristics. Bone marrow features potentially useful for distinguishing the two entities have not been thoroughly investigated and, currently, clinical history is used for purposes of disease classification. This study describes in detail the morphologic features of 23 cases of post-polycythemic myelofibrosis and 15 cases of primary myelofibrosis with a similar degree of fibrosis, from two large medical centers. Cytogenetic results were available in 19 post-polycythemic myelofibrosis and in 13 primary myelofibrosis cases. JAK2 status and follow-up information was available in all cases. Cellularity was increased in both groups, but more so in post-polycythemic myelofibrosis than in primary myelofibrosis. In post-polycythemic myelofibrosis, most megakaryocytes retained polycythemia vera-like features including normally folded and/or hyperlobulated nuclei devoid of severe maturation defects; only in a few cases were rare tight clusters present. In primary myelofibrosis cases, megakaryocytes showed pronounced anomalies, including increased nuclear:cytoplasmic ratio, abnormal clumping of chromatin and frequent tight clustering. No differences in blast number (<1%) or in the myeloid:erythroid ratio were observed. Post-polycythemic myelofibrosis showed a higher degree of karyotypic alterations and higher percentage of cases with complex karyotype and/or two or more clones. Chromosome 1 defects were common in post-polycythemic myelofibrosis, whereas isolated del(20q) was the most common alteration in primary myelofibrosis. No survival differences were noted between the two groups. Post-polycythemic myelofibrosis cases retain a distinct megakaryocytic morphology that represents a useful clue for differential diagnosis. In addition, they more often display a complex karyotype than do primary myelofibrosis cases. These results suggest that myelofibrosis in polycythemia vera represents a form of progression characterized by profound genetic damage whereas in primary myelofibrosis it is an intrinsic part of the phenotypic manifestation of the disease, not necessarily associated with adverse cytogenetics.

Severe delayed postpolypectomy bleeding in elder patient with post-polycythemia myelofibrosis

BackgroundThe interest of the case lies in an unexpected delayed bleeding following an endoscopic procedure in a patient with post-polycythemia myelofibrosis. The case gives the opportunity to discuss the medical management and monitoring of patients with myeloproliferative disorders undergoing minimally invasive surgery interventions.Case presentationA 75 years old woman affected by post-polycythemia myelofibrosis underwent endoscopy polypectomy followed by a delayed major local bleeding. At the time of the endoscopy followed by bleeding, the platelet count was 837 × 109/L, haemoglobin 113 g/L, PCV 35,2% and WBC 20.22 × 106/L. No antithrombotic prophylaxis with low molecular weight heparin was used. Antiplatelet drug was withdraw seven days before endoscopy and restarted one week after the procedure. Polyp size was 11x19 mm and it was located on right side of the colon.Fourteen days after procedure the patient developed a severe lower intestinal bleeding, which required RBC transfusion; the bleeding was in the site of polypectomy as demonstrated by arteriography; selective embolization of the three branches of the ileo-colic artery resolve the haemorrhage.ConclusionThere are some patients in whom current guidelines do not apply and our case stress the importance of myeloproliferative neoplasms as a risk factor for complications of endoscopic polypectomy. The delayed haemorrhage we observed suggest to strictly control the patient for a period longer than only one week also in case of antithrombotic treatment with antiplatelet drugs.

Results of A Phase I Study of Ruxolitinib in Patients (pts) with Relapsed/Refractory Acute Leukemia

AbstractAbstract 3617 Background:Outcomes in the treatment of AML remain overall poor. Novel targeted approaches to therapy are warranted. Ruxolitinib is a potent JAK1 and JAK2 inhibitor recently approved in the US for treatment of intermediate or high-risk myelofibrosis (MF), including primary MF, post-polycythemia MF, and post-essential thrombocytopenia MF and is being actively investigated as treatment for pts with acute leukemia. Objectives:To determine safety, maximum tolerated dose (MTD) and dose-limiting toxicity (DLT) of ruxolitinib in treatment of relapsed/refractory acute leukemia pts (AML or ALL). Methods:We conducted a single-center prospective phase I clinical trial (n=27) in which 3 different dose levels were tested (mg, oral, BID): 50 (n=4), 100 (n=5), 200 (n=18) as continuous daily dosing. One cycle of therapy was defined as 28 days. Inclusion criteria: Age >14 years, relapsed/refractory AML or ALL, adequate organ function (ALT and/or AST ≤1.5x upper limit of normal and serum creatinine ≤2.5mg/dL, ECOG PS 0–2, at least 2 weeks from prior leukemia therapy with exception of hydroxyurea. Toxicities were defined with CTCAE criteria, v4.0. Results:A total of 27 pts with acute leukemias were enrolled. All but one pt had AML (one pt with B-ALL). Median age at diagnosis was 66 years (range 25–88 years). 14 pts (52%) were male. 11 pts (41%) were PS=2 at enrollment. 5 pts had splenomegaly at baseline (range 4–21 cm). Baseline median laboratory parameters included: Hb (g/dL)= 9.2 (7.9–10.9), platelet (109/L)=22(3–271), WBC (109/L) =4(0.3–42.8), Blast % (PB)=23(0–97), Blast % (BM)=56 (1–99). The pt with only 1% BM blasts prior to starting therapy had persistent AML represented by extramedullary disease requiring further treatment. Baseline cytogenetics: diploid (n=9), Trisomy 8 (n=1), −5/-7/both (n=8), abnormal 11q (n=1), miscellaneous (n=8). Baseline molecular mutations: JAK2V617F (n=5), NRAS (n=3), MPL (n=1), FLT3-ITD (n=1), NPM1 (n=1), CEBPA (n=1), IDH2 (n=1), DNMT3a (n=1). Majority of pts (23 pts, 85%) were treated in salvage 2 (S2) or beyond: S2-S3 (n=11), ≥S4 (n=12). 7 pts had a prior non-leukemia malignancy (mantle cell lymphoma, breast, colon, lung, prostate, melanoma, T-cell lymphoma), all 7 of whom required prior chemotherapy, radiation, or surgery. 16 pts had prior diagnosis of either MPN or MDS. Median number of treatment cycles on protocol was 2 (range 1–4). Among 27 pts enrolled, 12 pts were found to be evaluable for DLT-assessment, responses below in Table. Only one pt required a dose reduction during study period (during cycle 3, from 200mg BID to 150mg BID in setting of drug-related Grade 3 thrombocytopenia). Most common Grade ≥3 non-hematologic event was infection (n=17)(most commonly pneumonia (n=9); most commonly occurring at 200mg po BID dosing level (8/17, 47%), followed by stroke (n=2), cerebral edema (n=1), fatigue (n=1), mucositis (n=1), elevation of alkaline phosphatase (n=1). 1 pt had CRp at 200mg po BID dosing (68 year old AML pt, received 6 prior AML therapies, Trisomy 8-positive, JAK2 mutation negative; achieved CRp after 2 cycles and was on study for total of 3 cycles). Among the 5 JAK2-positive pts, 4 were evaluable for response; median number of cycles was 1(range 1–3) and no CR/CRp were noted among this group. Conclusion:In this heavily pre-treated cohort of acute leukemia pts, 1 CRp was noted at highest dosing level (200mg po BID), in a relapsed/refractory AML pt, however this response was short (1 cycle). Most common grade ≥3 non-hematologic event during study period was infection, with pneumonia being most commonly reported.TableResponse Parameters by Ruxolitinib Dose for 28 day Protocol Evaluable Pts (n=12)N (%)Dose level (mg, oral, BID)50100200OverallTotal # enrolled451827Total # evaluable32712CRp001 (14)1 (8)Total number of courses11 (33)2 (100)2 (29)5 (42)≥ 22 (67)05 (71)7 (58) Disclosures:Off Label Use: Ruxolitinib off label investigational drug. Cortes:Incyte: Research Funding. Ravandi:Incyte: Research Funding. Verstovsek:Incyte: Research Funding.

An open-label, multicenter, expanded access study assessing the safety and efficacy of oral ruxolitinib administered to patients with primary myelofibrosis (PMF), post-polycythemia myelofibrosis (PPV MF) or post-essential thrombocythemia myelofibrosis (PET-MF).

TPS6640 Background: Myelofibrosis (MF) can be primary in origin or can progress from polycythemia vera (PPV-MF) or essential thrombocythemia (PET-MF). MF is characterized by cytopenias, reactive bone marrow fibrosis, splenomegaly, and constitutional symptoms including weight loss, fever, and night sweats. MF is associated with dysregulation of the Janus kinase pathway, irrespective of JAK2V617F mutation status. Recently, ruxolitinib (INCB018424) was approved for the treatment of MF on the basis of results from 2 phase 3 trials (COMFORT-I and -II). These trials demonstrated marked reductions in splenomegaly and symptom burden, and improvements in health-related quality of life (QoL) measures. Methods: JAK Inhibitor rUxolitinib in Myelofibrosis Patients (JUMP) is a global, phase 3b expanded access trial (NCT01493414) designed to assess the safety and efficacy of ruxolitinib in adult pts with PMF, PPV-MF or PET-MF who are treatment naïve, and are intolerant of, or had progressed on any prior therapy. Inclusion criteria: peripheral blast count of &lt;10%, adequate liver and renal function and intermediate-2 or high risk MF according to IPSS criteria or intermediate-1 risk MF with palpable spleen length ≥ 5 cm. The primary endpoint is to assess the safety of ruxolitinib. Additional endpoints include the proportion of pts with a &gt; 50% reduction in palpable spleen length, % change in white blood cell and platelet counts from baseline (BL), and change in packed red blood cell transfusion requirements. Changes from BL in QoL scores will be assessed using validated ECOG PS, FACT-Lymphoma, and FACIT instruments. Pts with a BL platelet count &gt; 200,000/μL will receive oral ruxolitinib 20 mg BID; pts with a BL platelet count of 100,000/μL to 200,000/μL will receive 15 mg BID; dose modifications are permitted for safety and efficacy. Global enrollment is open and currently includes 277 pts. This is planned to be the largest study ever conducted in pts with MF. [Table: see text]

Complex hypereosinophilia arising from post-polycythemia vera myelofibrosis: A case of imatinib-responsiveness

The classical myeloproliferative neoplasms (MPNs) feature an overproduction of mature blood elements. Phenotypic conversion, including transformation to myelofibrosis (MF) in those with antecedent ET and PV is a feared complication. Hypereosinophilic syndromes (HESs), especially those with myeloproliferative variants, can display similar features, including organomegaly, marrow fibrosis, clonality, thrombotic tendencies, and acute myeloid leukemia (AML) transformation. However, this group of illnesses is typically clinically and molecularly distinct from the classical MPNs. We report a case of a 59-yr-old woman with complex hypereosinophilia in the setting of post-polycythemic myelofibrosis (post-PVMF), with multi-system end-organ damage characteristic of HES.

Disruption of the ASXL1 gene is frequent in primary, post-essential thrombocytosis and post-polycythemia vera myelofibrosis, but not essential thrombocytosis or polycythemia vera: analysis of molecular genetics and clinical phenotypes

The myeloproliferative neoplasms, essential thrombocytosis, polycythemia vera and primary myelofibrosis, share the same acquired genetic lesion, but the concept of JAK2 V617F serving as the sole lesion responsible for these neoplasms is under question, and there has been interest in identifying additional mutations that may contribute to disease pathogenesis. Because ASXL1 lesions have been increasingly identified in myeloid neoplasms, we examined the relationships of ASXL1 mutation or deletion to both clinical phenotype and associated molecular features in 166 patients with myeloproliferative neoplasms. Exon 12 of ASXL1 was amplified from neutrophil genomic DNA and bidirectionally sequenced in 77 patients with myelofibrosis (including patients with primary and post-essential thrombocytosis or post-polycythemia myelofibrosis), 42 patients with polycythemia vera, 41 with essential thrombocytosis and 6 with post-myelofibrosis acute myeloid leukemia. Pyrosequencing assays were designed to determine the allele percentages of JAK2 V617F (G5073770T), ASXL1 2475dupA, and ASXL1 2846_2847del in neutrophil genomic DNA samples. Clinical and laboratory characteristics of patients with wild-type and ASXL1 mutations were then compared. We identified nonsense mutations or hemizygous deletion of ASXL1 in 36% of the patients with myelofibrosis, but very rarely among those with polycythemia vera or essential thrombocytosis. Among the patients with myelofibrosis, those with ASXL1 lesions were not distinguished from their wild-type counterparts with regard to JAK2 V617F status, exposure to chemotherapy or evolution to leukemia. Myelofibrosis patients with ASXL1 lesions were more likely to have received anemia-directed therapy compared to those without lesions [15/26 (58%) versus 11/39 (23%); P=0.02]. Using serial banked samples and quantitative ASXL1 mutant allele burden assays, we observed the acquisition and accumulation of ASXL1 mutations over time in two patients with post-essential thrombocytosis myelofibrosis. ASXL1 haploinsufficiency is associated with a myelofibrosis phenotype in the context of other known and unknown lesions, and disruption of ASXL1 function may contribute to the disease pathogenesis of myelofibrosis.

Gene Expression Profiling with Principal Component Analysis Depicts the Biological Continuum From Essential Thrombocythemia Over Polycythemia Vera to Myelofibrosis

AbstractAbstract 4115 Introduction:The classical Philadelphia-negative chronic myeloproliferative neoplasms (CMPNs) encompass polycythemia vera (PV), essential thrombocythemia (ET), and primary myelofibrosis (PMF). After several years, a proportion of patients with PV may develop increasing splenomegaly and bone marrow fibrosis to terminate in postpolycythemic myelofibrosis, which then has a very poor prognosis with median survival of only a few years. A high proportion of the ET-population has been shown to have prefibrotic PMF or a “PV-like” phenotype, which after a variable time may terminate in myelofibrosis with myeloid metaplasia (MMM). Although the concept of prefibrotic myelofibrosis as a separate disease entity to be distinguished from ET by distinct histopathological features has been questioned, it seems logical that a continuum exists from “early” myelofibrosis with no or minimal bone marrow fibrosis to the advanced stage of myelofibrosis with myeloid metaplasia. Accordingly, a new concept of these diseases as a biological continuum from ET over PV to PMF has emerged. Indeed, this biological continuum reflects the various clinical stages as also described for chronic myelogenous leukaemia (CML) – a chronic stable phase (ET-PV), an accelerated phase (transitional phase), and a terminal myelofibrosis or blast phase of the disease (PMF-BP).It is evident that the JAK2 V617F mutational load is an important determinant of phenotype, but other genetic and epigenetic events contribute to the phenotypic presentation. Several gene expression studies have identified genes which might be of pathogenetic relevance for the development of CMPNs. However, no study has applied an unsupervised method as Principal Component Analysis (PCA) to discover unknown trends in the data. We have carried out gene expression profiling with PCA to ascertain if this analysis might unravel distinct grouping of disease entities supporting the biological continuum from early ET over PV to the advanced myelofibrosis phase. Patients and Methods:Using HG-U133 Plus 2.0 microarray from Affymetrix, recognizing 54675 probe sets (38500 genes), gene expression microarray studies have been performed on control subjects (n=21) and patients with ET (n =19), PV (n=41), and PMF (n=9). An unsupervised statistical method, PCA, which is an exploratory tool used to uncover unknown trends in the data based on gene expression profiles, was applied to the data. Results:The results from the PCA confirm the hypothesis of a biological continuum from control subjects over ET to PV and finally PMF (figure 1). The figure also reveals that patients with PV in a transitional stage (PVtrans) with pancytosis, huge splenomegaly, and bone marrow fibrosis have a gene profile between PV and PMF. Furthermore, single gene analysis revealed that several genes are highly dysregulated in patients with ET, PV, and PMF compared to control subjects even after correcting for multiple testing. Discussion and Conclusions:Using global gene expression profiling with PCA in patients with different CMPNs (ET, PV, PMF), we have yielded support to the concept of a biological continuum from early ET to the advanced myelofibrosis stage. Studies are in progress to identify single genes or clusters of genes accounting for the biological continuum and accordingly the progression from ET over PV to myelofibrosis. Disclosures:No relevant conflicts of interest to declare.