Bone Marrow Fibrosis Grade Research Articles

Burden of Disease and Clinical Responses in Low and Intermediate-1 Risk Myelofibrosis Patients Treated with Ruxolitinib

Myelofibrosis (MF) is a hematologic neoplasm characterized by variable degrees of cytopenias/ myeloproliferation, extramedullary hematopoiesis, disease-related constitutional symptoms and an increased risk for acute myeloid leukemia (AML) transformation. Ruxolitinib, a JAK1/2 inhibitor is FDA approved for the management of intermediate to high-risk MF. However, intermediate-2 and high-risk MF patients accounted for 99% of patients (pts) in the 2 pivotal trials that led to the approval of ruxolitinib in North America, Australia and Europe (COMFORT 1 and COMFORT 2 studies). However, even low and intermediate-1 (int-1) risk MF pts could have a high burden of disease. Here we report our experience of using ruxolitinib in MF pts stratified as low and int-1 risk by the Dynamic International Prognostic Scoring System (DIPSS). A total of 25 pts with low and Int-1 risk disease were treated with ruxolitinib at the Cleveland Clinic and Northwestern University. The median age of the cohort was 61 yrs (range=33-87; males=9, females=16). The median total symptom score (TSS) by Myeloproliferative Neoplasm Symptom AssessmentForm (MPN SAF) was 20. The median pre-treatment spleen size by palpation was 13 cm below the left costal margin. Baseline median bone marrow (BM) fibrosis grading was 2 (on a scale 0-3; grade 1 N=3, grade 2 N=11, and grade 3 N=11). The indications for starting ruxolitinib were constitutional symptoms (fatigue N=20, night sweats N=4, pruritus N=1) and splenomegaly (N=13). The median starting dose was 5 mg twice daily, 10mg twice daily at 3 months and 6 months, and 5mg twice daily at 12 months. The median dose at last follow up was 10 mg twice daily. The median duration of treatment was 12 months. There was a median 73% reduction in the MPN SAF TSS compared to baseline (P< 0.001). There was improvement in each of the parameters of the TSS. The percentage of reduction in spleen size by palpation at 3, 6, 12 months was 49, 57, and 64%, respectively. In 5 patients who had a repeat BM biopsy, there was an improvement in their BM fibrosis by at least 1 grade (N=3), stable fibrosis (N=1) or increased fibrosis (N=1). Hematologic adverse events were reported at 3, 6, 12 months of treatment. Using Common Terminology Criteria for Adverse Events (CTCAEv4.0), there were seven with grade 3/4 anemia and six with grade 3/4 thrombocytopenia. Non-hematologic adverse events reported at 3, 6, 12 months of treatment included dizziness (N=1), headaches (N=1) and infections (pneumonia N=2, cellulitis N=2, perineal abscess N=1, Herpes Zoster N=2, and gluteal abscess after BM biopsy N=1; only one required hospitalization). Ruxolitinib was discontinued in 5 patients due to lack of clinical response (N=3) and grade 3/4 anemia/thrombocytopenia (N=2). The remaining 20 patients are still on treatment. None of the pts progressed to AML or died. The median follow up of our cohort was 27 months. Further, using a multi-Analyte ELISArray Kit, plasma concentrations of interleukins (IL):IL1A, IL1B, IL2, IL4, IL6, IL8, IL10, IL12, IL17A, INFg, TNFa and GM-CSF were measured in low/int-1 risk pts (N=3) and intermediate-2/high risk patients (N=4) and no statistically significant difference was found between the two risk groups (P>0.05) further supporting the high burden of disease observed even in low and int-1 risk MF patients. In conclusion, pts with low/int-1 risk MF have a high burden of disease and can achieve meaningful clinical responses to ruxolitinib similar to int-2/ high risk MF pts without severe toxicity. Larger studies are needed to further evaluate the safety and efficacy of ruxoltinib in this patient population. DisclosuresNo relevant conflicts of interest to declare.

Ruxolitinib Therapy Effectively Modulates CD34+ Hematopoietic Progenitors and Bone Marrow Angiogenesis in Patients with Myelofibrosis

Background: Myelofibrosis (MF) associated with myeloproliferative neoplasms (MPN) is a multifactorial process resulting from profound modifications of the bone marrow (BM) and spleen stroma, as demonstrated by the presence of reticulin and collagen fibrosis, osteosclerosis and neo-angiogenesis. These stromal accumulations suggest a deregulation of BM stem cell niches, in which hematopoietic progenitor cells (HPCs) are engaged in a constant crosstalk with their stromal environment. Recently, there is strengthening evidence that the BM microenvironment which might contribute to the clinical outcomes in MF can be effectively modulated by JAK inhibitor therapy.Methods: A total of 68 patients (pts) with primary, post polycythemia vera or essential thrombocythemia MF, presenting at baseline (BL) with various degrees of BM fibrosis according to the WHO grading system, were selected from a phase 1/2 study (NCT00509899). All cases had both a BL and a sequential BM biopsy taken at 24 months (mo) following therapy with the JAK1/2 inhibitor ruxolitinib (RUX). Analysis included immunohistochemical and morphometric assessment of CD34+ HPCs (overall frequency, clustering index) by consensus after independent blinded review by 3 pathologists and computer assisted evaluation of BM angiogenesis. Quantification of microvascular density (MVD), luminal dilatation or microvessel area (MVA), and additional parameters, such as shape (form factor), tortuosity, and branching (maximal vessel length), were performed by whole slide digital imaging of the trephine biopsy and subsequent image processing using the ImageJ system. For 16 pts, additional analyses for vascular endothelial growth factor (VEGF) expression at BL and 24 mo were performed.Results: At BL, 79.5% of MF pts presented with a BM fibrosis grade of 2 or 3 according to the WHO definition. Following RUX therapy, 73.5% of cases showed an improvement or stabilization and in 6 pts (8.8%) a further regression to an earlier disease stage was observed. Increase in BM fibers was conspicuously accompanied by higher MVD and MVA at BL, which was also associated with elevated levels of angiogenic cytokines like VEGF. The structure of vessels at BL was significantly altered with an enhanced irregularity of shape and tortuosity. Post-RUX BM samples revealed a reduction in MVD -and in particular MVA- independent of BM fibrosis response. However, cases with improvement in fibrosis post-RUX showed a more profound change in microvessel architecture. Normalization of vessel structure was accompanied by a significant reduction of VEGF expression levels at 24 mo (p < 0.001). Overall frequency and clustering of CD34+ HPCs was reduced by RUX therapy at 24 mo. Improvement or stabilization of BM fibrosis post-RUX was in most cases associated with a corresponding reduction of CD34+ HPCs (88.9%) and a decreased clustering index (77.7%). In this regard, modulation of CD34+ HPCs was associated with a greater spleen size reduction at 24 mo (-10.9 vs -9.7 cm, p=0.061), whereas changes in hemoglobin values and platelet counts showed no correlation to this parameter. Similar effects were observed for MVD, MVA, and additional morphometric alterations of BM microvessel architecure.Conclusions: Our results support previous reports that therapy with the JAK inhibitor RUX effectively modulates the abnormal microenvironment that contributes to the maintenance of the neoplastic clone. In this regard, it is tempting to speculate that RUX therapy might modify vascular niches and therefore could impact the abnormal trafficking and homing of CD34+ HPCs and endothelial precursors that characterize MF. DisclosuresKvasnicka:Novartis: Consultancy, Honoraria, Research Funding; Incyte Corporation: Consultancy, Honoraria. Thiele:Novartis: Consultancy, Honoraria; Incyte Corporation: Consultancy, Honoraria. Verstovsek:Incyte Corporation: Research Funding.

Long-Term Effects of Ruxolitinib on Bone Marrow Morphology in Patients With Myelofibrosis and Comparison to Best Available Therapy

Context: Ruxolitinib is a JAK1/JAK2 inhibitor that reduced splenomegaly and symptoms and was associated with improved survival in patients with myelofibrosis relative to placebo or best available therapy (BAT) in phase 3 studies. Objective: To evaluate the effects of long-term ruxolitinib treatment on bone marrow (BM) morphology in patients with myelofibrosis. Design and Patients: Trephine biopsies were obtained at baseline, 24 (68 patients), and 48 (18 patients) months from ruxolitinib-treated patients enrolled in a phase I/II trial (NCT00509899; Verstovsek, NEJM 2010). Two of the authors (JT, HMK) independently quantified BM fibrosis and a third (CB-R) reviewed the findings. Reviewers were blinded to patient characteristics and outcomes. BM fibrosis grading was determined in prospectively collected specimens from 139 patients (160 biopsies) treated for 24 (97 patients) and 48 (63 patients) months receiving BAT from an independent, multicenter, observational database. BAT included hydroxyurea (47%), interferon-alpha (7%), assorted sequential therapies (25%), or supportive-only therapy (21%). Outcome Measure: BM fibrosiswasgraded per the World Health Organization (WHO) criteria (scale: 0-3). Changes in BM fibrosis grade versus baseline were categorized as improvement, stabilization, or worsening. Results: At baseline, 21% of ruxolitinib-treated patients had grade 1, 53% grade 2, and 26% grade3BM fibrosis;approximately50%ofpatientshadosteosclerosis at baseline (grade 1: 33%; grade 2: 9%; grade 3: 9%). Collagen accumulation was observed in 32 cases (47%): 30% grade 1, 18% grade 2/3. There were no differences in the distribution of baseline BM fibrosis grades between ruxolitinib and BAT (p¼0.441; CochraneManteleHaenszel test). A greater percentage of ruxolitinib-treated versus BAT-treated patients showed stabilization (24 months: 57% versus 54%; 48 months: 56% versus 46%) or improvement (24 months: 15% versus 6%; 48 months: 22% versus 2%) in BM fibrosis. Worsening (excluding patients with baseline grade 3 BM fibrosis) was more prevalent with BAT (24 months: 37% versus62%;OR[95%CI]:0.40[0.18,0.87],48months:25%versus 75%; OR [95% CI]: 0.11[0.03, 0.43]). Conclusions: Long-term ruxolitinib therapy may meaningfully delay BM fibrosis progression. A comparable effect was not seen with long-term BAT, which supports earlier observations with hydroxyurea (Kvasnicka ASCO

Contribution of comorbidities and grade of bone marrow fibrosis to the prognosis of survival in patients with primary myelofibrosis

The widely used current International Prognostic Scoring System (IPSS) for primary myelofibrosis (PMF) is based on clinical parameters. The objective of this study was to identify additional prognostic factors at the time of diagnosis, which could have an impact on the future treatment of patients with PMF. We conducted a study of 131 consecutive PMF patients with median follow-up of 44 months. Data on baseline demographics, clinical and laboratory parameters, IPSS, grade of bone marrow fibrosis (MF), as well as influence of concomitant comorbidities were analyzed in terms of survival. Comorbidity was assessed using the Adult Comorbidity Evaluation-27 (ACE-27) score and the hematopoietic cell transplantation comorbidity index. An improved prognostic model of survival was obtained by deploying the MF and ACE-27 to the IPSS. A multivariable regression analyses confirmed the statistical significance of IPSS (P<0.001, HR 3.754, 95% CI 2.130-6.615), MF>1 (P=0.001, HR 2.694, 95% CI 1.466-4.951) and ACE-27 (P<0.001, HR 4.141, 95% CI 2.322-7.386) in predicting the survival of patients with PMF. When the IPSS was modified with MF and ACE-27, the final prognostic model for overall survival was stratified as low (score 0-1), intermediate (score 2-3) and high risk (score 4-6) with median survival of not reached, 115 and 22 months, respectively (P<0.001). Our findings indicate that the combination of histological changes, comorbidity assessment and clinical parameters at the time of diagnosis allows better discrimination of patients in survival prognostic groups and helps to identify high-risk patients for a poor outcome.

Effects Of Five-Years Of Ruxolitinib Therapy On Bone Marrow Morphology In Patients With Myelofibrosis and Comparison With Best Available Therapy

BackgroundMyelofibrosis (MF) is characterized by progressive bone marrow (BM) fibrosis and ineffective, extramedullary hematopoiesis resulting in splenomegaly, debilitating symptoms, and shortened survival. So far, conventional pharmacotherapy had limited success in improving BM fibrosis. The JAK1/JAK2 inhibitor ruxolitinib (RUX) reduced splenomegaly and symptom burden and improved survival in patients (pts) with intermediate-2 or high-risk MF compared with placebo or best available therapy (BAT) in two phase 3 studies. We examined the effects of long-term RUX treatment on BM morphology in pts with MF from the MD Anderson Cancer Center enrolled in the phase 1/2 study (NCT00509899) and compared the results with a cohort of pts treated with BAT. MethodsTrephine biopsies of pts with primary MF (PMF), post-polycythemia vera MF, or post-essential thrombocythemia were obtained at baseline and at 24 (68 pts), 48 (38 pts), 54 (24 pts), 60 (10 pts) and 66 (4 pts) months (mo) of therapy. World Health Organization (WHO)-defined BM fibrosis grade (scale 0-3) was assessed independently by two authors (JT and HMK) and reviewed by a third author (CB-R). Final grade was determined by consensus, with all reviewers blinded to pt characteristics and outcomes. Accuracy of grading was validated in randomly selected biopsies by a consortium of 8 European LeukemiaNET hematopathologists. BM fibrosis grade in 192 pts with PMF treated with BAT for 24 (97 pts), 48 (63 pts), 54 (17 pts), 60 (9 pts), or 66 (6 pts) mo was determined from prospectively collected biopsies from an independent, multicenter, observational database. The majority of BAT patients were treated with hydroxyurea [HU], various sequential therapies, or watchful waiting; few pts were treated with interferon-alpha. Biopsies were performed at protocol-defined intervals for RUX-treated pts or at the discretion of the treating physician in BAT-treated pts, mostly based on changes in a patient's clinical condition. Changes from baseline in BM fibrosis grade were categorized as improvement, stabilization, or worsening. Changes over time in the extent of collagen deposition and osteosclerosis and in BM cellularity were evaluated in RUX-treated pts only. ResultsAt baseline, 22%, 53%, and 25% of the 68 eligible RUX-treated pts had BM fibrosis grade 1, 2, and 3, respectively. Baseline osteosclerosis grade 0, 1, 2, and 3 was present in 50%, 32%, 9%, and 9% of RUX-treated pts, respectively. Accumulation of collagen fibers at baseline was observed in 32 pts (47%), with 29% having mild (grade 1) and 18% having manifest (grade 2) or intense (grade 3) collagen deposition. BM fibrosis grade distribution at baseline did not differ significantly between RUX- and BAT-treated pts (p=0.308, Cochran–Mantel–Haenszel test). At 24, 48, and 60 mo, a greater percentage of RUX-treated pts experienced stabilization or improvement of BM fibrosis relative to their baseline status compared with BAT-treated pts. Worsening BM fibrosis was more prevalent in BAT-treated pts compared with RUX-treated pts (Table). The majority of RUX-treated pts experienced durable spleen size reductions; effect on spleen size was associated with improvement or stabilization of BM morphology. In RUX-treated pts, improvement or stabilization of BM fibrosis at 24 mo was associated with a reduced relative risk of death compared with worsening BM fibrosis at 24 mo. ConclusionsLong-term therapy with RUX may provide a clinically meaningful delay of BM fibrosis progression in pts with MF. The lack of a beneficial effect of long-term BAT is consistent with previous observations in a smaller cohort of HU-treated pts (Kvasnicka et al. ASCO 2013. Abstract 7030). Improvement or stabilization of BM fibrosis with RUX may be associated with more favorable outcomes. Results from this analysis support the importance of BM fibrosis as a prognostic marker in pts with MF. [Display omitted] Disclosures:Kvasnicka:Novartis: Consultancy; Incyte Corporation: Consultancy; Novartis: Research Funding; Incyte Corporation: Research Funding; Shire: Research Funding; AOP Orphan Pharmaceuticals: Research Funding; Novartis: Honoraria; Shire: Honoraria; Incyte Corporation: Honoraria. Thiele:AOP Orphan Pharmaceuticals: Consultancy; Incyte Corporation: Consultancy; Novartis: Consultancy; Shire: Consultancy; Sanofi: Consultancy; Novartis: Research Funding; Shire: Research Funding; AOP Orphan Pharmaceuticals: Honoraria; Incyte Corporation: Honoraria; Novartis: Honoraria; Shire: Honoraria; Sanofi: Honoraria. Sun:Incyte: Employment; Incyte: Equity Ownership. Cortes:Incyte, Sanofi: Consultancy; Incyte, Sanofi: Research Funding. Kantarjian:Ariad: Research Funding; Novartis: Research Funding; BMS: Research Funding; Pfizer: Research Funding. Verstovsek:Incyte Corporation: Research Funding.

Effect Of Treatment With The JAK2-Selective Inhibitor Fedratinib (SAR302503) On Bone Marrow Histology In Patients With Myeloproliferative Neoplasms With Myelofibrosis

IntroductionFedratinib, a JAK2-selective inhibitor, demonstrated clinical benefit through a reduction in splenomegaly and symptoms in patients with myelofibrosis (MF), including post-polycythemia vera MF (post-PV MF), post-essential thrombocythemia MF (post-ET MF) and primary MF (PMF), in Phase I and II studies (J Clin Oncol 2011;29:789; Haematologica 2013;98:S1113). Bone marrow fibrosis (BMF) has been associated with splenomegaly and cytopenias (Ann Hematol 2006;85:226). Hence, stabilization and/or reversal of BMF remain important therapeutic goals. This report represents an exploratory analysis of sequential BMF data from patients with MF in an open-label Phase I/II study to evaluate the long-term effects of orally administered fedratinib (TED12015; NCT00724334). MethodsPatients with intermediate or high-risk MF (Mayo Prognostic Scoring System) received fedratinib therapy in consecutive cycles (1 cycle = 28 days) as long as they derived clinical benefit. Bone marrow trephine biopsies were performed at baseline and after every 6 cycles. Hematoxylin and eosin, reticulin, and Masson's trichrome staining of core biopsy slides were used to grade BMF on a scale from 0 to 3 using the 2008 WHO MF grading criteria. BMF was graded independently in a blinded fashion by 3 hematopathologists. BMF grades were established as long as at least 2 of the 3 pathologists agreed independently. Changes in BMF grade from baseline were categorized as improvement (≥1 grade reduction), stabilization (no change), or worsening (≥1 grade increase). ResultsOf the 43 patients enrolled in the TED12015 study, the median fedratinib dose received was 473 (range 144–683) mg/day and median treatment duration was 32.3 (range 7–61) cycles. Bone marrow biopsies at baseline and at least one other time point were available for 21/43 (49%) patients, whose baseline characteristics were: median age 61 years (range 43–85); 57% male; 38% high-risk MF by WHO 2008 criteria (Leukemia 2008; 22:14); and 90% JAK2V617F positive. A consensus grade was achieved for 96% of the samples. At baseline, 2, 10, and 9 patients had grade 1, 2, and 3 BMF, respectively. Changes in BMF grade from baseline are shown in the figure. BMF improvement with 1 grade reduction was observed in 8/18 (44%) patients at Cycle 6. By Cycle 30, 4/9 (44%) evaluable patients had BMF improvement, including 2 patients with improvement by 2 grades and 2 patients with improvement by 1 grade. Of patients with Grade 3 BMF at baseline, 6/9 (67%) exhibited 1 grade improvement at Cycle 6. Two patients had 2 grades of BMF reduction from baseline during treatment (grade 3 to 1, and grade 2 to 0, both at Cycle 12), and the latter achieved a complete clinical remission at Cycle 30 assessed by IWG-MRT response criteria. The two patients who experienced complete reversal of BMF to grade 0 (one from grade 2 and one from grade 1) had normalization of not only hemoglobin level but also white blood cell and platelet counts at Cycle 18. [Display omitted] ConclusionsThese exploratory analyses suggest that a proportion of patients treated long-term with fedratinib demonstrate stable or improved BMF. The disease modifying impact of fedratinib on BMF changes will be further assessed in a randomized, placebo-controlled Phase III clinical trial (JAKARTA; NCT01437787). This study was sponsored by Sanofi. Disclosures:Jamieson:J&J, Roche: Research Funding; Sanofi: Membership on an entity's Board of Directors or advisory committees. Hasserjian:Sanofi, Inc: Consultancy. Gotlib:Sanofi: Travel to EHA 2012, Travel to EHA 2012 Other; Sanofi: Membership on an entity's Board of Directors or advisory committees; Sanofi: Research Funding. Cortes:Incyte, Sanofi: Consultancy; Incyte, Sanofi: Research Funding. Talpaz:Novartis, Bristol-Myers Squibb, Ariad, Deciphera: Research Funding; Novartis, Bristol-Myers Squibb, Ariad, Deciphera: Speakers Bureau. Thiele:AOP Orphan Pharmaceuticals, Incyte, Novartis, Shire, Sanofi: Consultancy; Novartis, Shire: Research Funding; AOP Orphan Pharmaceuticals, Incyte, Novartis, Shire, Sanofi: Honoraria. Rodig:Ventana/Roche Inc.: Research Funding; Daiichi-Sankyo/Arqule Inc., Ventana/Roche Inc., Shape Pharmaceuticals Inc.: Consultancy. Patki:Sanofi: Employment. Wu:Sanofi: Employment. Wu:Sanofi: Employment. Pozdnyakova:Sanofi: Honoraria; Sanofi: Consultancy.

Ruxolitinib Treatment Outcome In a Patient With Secondary Chronic Myelomonocytic Leukemia

Chronic myelomonocytic leukemia ( CMML) is a de novo myelodysplastic/myeloproliferative disease with an unfavorable prognosis. Secondary CMML cases are rare and sporadically reported. Published data have shown that development of monocytosis in patients during the course of PMF or MDS is associated with poor prognosis (M.A. Elliott, Leukemia Research, 31 (2007).Essential thrombocythemia (ET) is an indolent myeloproliferative disorder characterized by long symptom-free intervals. Uncommonly, few patients with ET may develop bone marrow (BM) fibrosis which to be distinguished from cases with early PMF accompanied by thrombocytosis. Progression to acute leukemia or myelodysplastic syndrome (MDS) occurs in < 5% of patients and is likely related to previous cytotoxic therapy.We report here a rare case of a patient with ET who developed BM fibrosis and rapidly progressed to a secondary myelomonocytic leukemia.A 54 years old female patient, diagnosed with ET in 2003, as she presented a persistent isolated high platelet count of 700 G/L, with normal white blood cells (WBCs): 8 G/L, hemoglobin (hb): 15 g/dl, monocytes: 0.5 G/L and no splenomegaly. She was treated with Anagrelide 1.5 -2 mg daily due to intolerance to hydroxyurea. No major event has been declared during the last 10 years and a median platelet count of 450 G/L.In January 2013, a routine check-up showed leukocytosis (WBCs: 25 G/L), slight anemia (hb: 11.6 g/dl), with relative thrombocytopenia, 266 G/L, monocytosis: 2 G/L with 3% circulating blasts and a palpable spleen. The bone marrow biopsy revealed BM fibrosis grade III and 7% of blasts. Progression to secondary myelofibrosis was declared and treatment with hydroxyurea was initiated to control peripheral blood counts prior to transplantation. Treatment with ruxolitinib started in May, at a dose of 20 mg bid due to failure of blood count reduction with hydroyurea. A rapid decline in WBCs count to 3 G/L was achieved but with sustained median monocytosis of 1.4 G/L. The patient developed marked anemia (7.5 g/dl) as well as thrombocytopenia (13 G/L) and ruxolitinib was interrupted by the end of June 2013.Within 15 days, the patient showed rapid progression, her WBCs count attained 105 G/L, anemia and thrombocytopenia persisted. The absolute monocyte count increased up to 66 G/L with marked dysplastic features and morphological shifting to aspects compatible with overt secondary myelomonocytic leukemia in both blood and bone marrow smears, 3% circulating and 8% bone marrow blastes (WHO criteria for CMML diagnosis). Molecular studies showed the presence of JAK2 V617F allele burden at 66% and absence of BCR/ABL transcript. Only two mitosis, with an unidentified additional marker were obtained on chromosome analysis. Unfortunately, the patient died 2 weeks later.This observation shows the adverse prognostic development of monocytosis in ET which is similar to that published in PMF in 10 patients (Leonardo Boiocchi, Modern pathology, 2013), thus requiring particular attention in the treatment of these patients. As chromosomal analysis was unavailable at diagnosis, we weren't able to prove the presence of clonal heterogeneity, a concept developed recently to explain the mechanism of development of two different diseases.Ruxolitinib is an inhibitor of JAK1 and JAK2 resulting in a dramatic decrease in cytokines and growth factors that are important for hematopoiesis and growth function. Of note, in this case, ruxolitinib which was administrated for the treatment of 2ry myelofibrosis, inhibited as well the increase in monocytosis and controlled the progression of CMML evidenced by the remarkable increase in dysplastic monocytes after its interruption. To our knowledge a clinical trial is actually on going to assess if its administration can improve the outcome of patients with CMML and the optimal dose to be administrated. Disclosures:No relevant conflicts of interest to declare.

Discrepancy in diagnosis of primary myelofibrosis between referral and tertiary care centers

Primary myelofibrosis (PMF) is myeloproliferative neoplasm whose diagnosis is based on a combination of clinical and pathology criteria. We evaluated 560 consecutive patients who were diagnosed with PMF upon a referral to our center and evaluated the frequency of and reasons for diagnostic discordance. Discordance in the diagnosis was found in 70 (12.5%) patients. Discordant cases had a significantly lower grade of bone marrow fibrosis (grade 0-1), more likely to be JAK2V617F-mutation negative, and have no peripheral blood blasts, possibly explaining the difficulty in making a proper diagnosis and underscoring the need for a complete evaluation at a tertiary center.

Exploratory analysis of the effect of ruxolitinib on bone marrow morphology in patients with myelofibrosis.

7030 Background: Myelofibrosis(MF) is characterized by splenomegaly, burdensome symptoms, progressive bone marrow (BM) fibrosis, and shortened survival. Ruxolitinib (Rux), an oral, FDA-approved JAK1/JAK2 inhibitor, has demonstrated improvements in spleen volume, symptoms, and survival in patients (pts) with MF. This study was conducted to explore possible effects of long-term Rux treatment on BM morphology in MF. Methods: Trephine biopsies were obtained at baseline, 24 (67 pts), and 48 (17 pts) months (mo) from the cohort of MF patients treated at MD Anderson Cancer Center who participated in a phase I/II trial of Rux (NCT00509899). The clinical outcomes from this trial have been published previously [Verstovsek, NEJM 2010]. Two of the authors (JT and HMK) independently evaluated the World Health Organization (WHO)-defined BM fibrosis grade (0-3). Reviewers were blinded to pts characteristics and outcomes and consensus decided discordant scores. For demonstrative purposes, WHO BM fibrosis grading was also determined for a control cohort of pts treated with hydroxyurea (HU) for 24 (31 pts) and 48 (20 pts) mo. Changes in BM fibrosis grade vs. baseline were calculated for 24 and 48 mo, and categorized as improvement, stabilization, and worsening for each patient. Results: A higher percentage of Rux-treated pts showed stabilization or improvement of BM fibrosis at both 24 and 48 mo than the HU-treated pts. Worsening was greater in the HU-treated cohort at both time points. Conclusions: This exploratory analysis of long-term exposure to Rux in MF provides the first indication that JAK inhibitor therapy may be able to meaningfully retard advancement of BM fibrosis. A comparable effect was not seen with long-term HU therapy. Additional research is needed to further elucidate these findings. Clinical trial information: NCT00509899. [Table: see text]

Compassionate Use Program (CUP) with Ruxolitinib in Mexican Patients with Primary Myelofibrosis (PMF), Post – Polycythemia, Vera Myelofibrosis (PPV – MF), and Post–Essential Thrombocythemia Myelofibrosis (PET – MF)

AbstractAbstract 5067 IntroductionMyelofibrosis (MF) is a myeloproliferative neoplasm (MPN) that is characterized by ineffective hematopoiesis and symptomatic burden such as cytopenias, and splenomegaly. The prevalence of MF symptoms is relatively uniform across the 3 main subtypes: primary MF (PMF), post – polycythemia vera MF (PPV MF), and post – essential thrombocythemia MF (PET MF). Available therapies (AT) in Mexico, includes hydroxyurea (HU), interferon (IFN), for ET, besides phlebotomy for PV, as well as androgens, steroids, chemotherapy, IFN, thalidomide, EPO and radiotherapy for PMF. The only potentially curative therapy is allogeneic hematopoietic stem cell transplantation (HSCT) but treatment-related mortality remains high. Recently ruxolitinib an oral Janus kinase–2 inhibitor (JAK-2) has been approved to treat patients with MF. The safety and efficacy of Ruxolitinib has been evaluated 528 patients from COMFORT I and COMFORT II trials. ObjectiveTo report the first clinical experience in a CUP with an oral JAK–2 Inhibitor (ruxolitinib) in 40 MF patients refractory to AT in Mexico. Patients and MethodsPMF patients and PPV/PET MF eligible for the ruxolitinib CUP, were diagnosed according to the 2008 WHO criteria, irrespective of JAK2 mutation status; classified as high risk; intermediate risk level 2; or, intermediate risk level 1 with an enlarged spleen; with a peripheral blood blast count of < 10%; adequate renal and liver function, platelet count >100×109/L, all of them were treated with best available therapies in Mexico. Therapy with ruxolitinib was administered to all patients. Doses were adjusted according to the platelet counts.Clinical and demographic characteristics were assessed at baseline and during the follow-up. The analyzed characteristics were: Demographic: age, gender; Clinical: Risk group, Bone marrow fibrosis grade, spleen size, ECOG, MPN subtype, JAK mutation, CBC counts;Spleen size at baseline and at week 20 of treatment. ResultsThe median age was 64. 2 (Interval 41 – 75). Gender distribution was 46% female and 54% male. Patients according to the International Prognostic Scoring System (IPSS) were distributed in the following risk category: 10% low risk; 53. 3% intermediate – 1 risk; 26. 7 % intermediate – 2 risk; and 20% high risk. Bone marrow fibrosis grade distribution was: Grade I 46. 15%; Grade II 23. 07%; Grade III 30. 76%. Spleen length below costal margin: <10 cm, 80. 7%; 10 to <20 cm, 11. 5% and > 20 cm, 7. 7% of patients. Spleen Average size was 9. 58 cm below costal margin at the beginning of treatment. ECOG 0 was present in 15% of patients; ECOG 1, 73%; and ECOG 2, 12% of patients. The disease subtype distribution was: PMF 45%; PPV-MF 36% and PET-MF 46%. JAK mutation was positive for 19% of patients, 46% were negative, and 35% did not have mutation analysis.The findings from the baseline to week 20 were: Splenomegaly decreased from 9. 58 cm (avg) to 4. 5 cm (avg) (53. 02% of reduction); Median Hemoglobin level was 13. 2 gr/dL at baseline versus 10. 24 gr/dL (22. 42% of decrease). Median Platelet count was 437, 000/mm3 at baseline versus 341, 503/mm3 at week 20 of treatment (21. 85% of decrease).Median time of treatment is 20. 1 weeks.Hematologic adverse events presented: Hemoglobin level decrease events (CTCAE grade 2 and 3) resolved with transfusion support. Platelet count decreases (CTCAE grade 2) were transitory and resolved after two weeks of treatment interruption. ConclusionData showed demonstrate principal characteristics of this MF cohort. Until recently, most treatments provided only palliative care with no single treatment addressing all of the complications and symptoms of the MF. Ruxolitinib showed a primary therapeutic benefit as reduction in splenomegaly and significant improvement in MF-related symptoms in this cohort of Mexican patients with myelofibrosis. Disclosures:No relevant conflicts of interest to declare.

The European Consensus on grading of bone marrow fibrosis allows a better prognostication of patients with primary myelofibrosis

We investigated the relationship between the International Prognostic Scoring System of the International Working Group for Myelofibrosis Research and Treatment and the European Consensus on grading of bone marrow fibrosis (MF) in patients with primary myelofibrosis. We compared them in 196 consecutive primary myelofibrosis patients (median follow-up 45.7 months; range 7.4–159). International Prognostic Scoring System classified 42 cases as low risk, 73 as intermediate risk-1, 69 as intermediate risk-2, and 12 as high risk; European Consensus on grading of bone marrow fibrosis classified 83 cases as MF-0, 58 as MF-1, 41 as MF-2, and 14 as MF-3. By the time of the analysis, 30 patients (15.3%) had died. Overall median survival was 3.8 years (95% confidence interval: 3.3–4.3). Multivariate analysis confirmed that both scoring systems independently predicted survival, with hazard ratios similar to those provided by univariate analysis (respectively, 2.40 (95% confidence interval: 1.47–3.91) and 2.58 (95% confidence interval: 1.72–3.89) but the likelihood ratio increased from 19.6 of the International Prognostic Scoring System or 29.0 of the European Consensus on grading of bone MF to 42.3 when both measures were considered together. Analysis of the overall survival curves documented that patients classified as having the most favourable rate with both prognostic scores (ie low risk and MF-0) survive longer than those with only one favourable score (ie low risk but MF >0 or MF-0, but International Prognostic Scoring System >low risk). In contrast, those patients classified as having the most unfavourable rate for both scores (high risk and MF-3) have a shorter survival than those with only one unfavourable score (ie high risk but MF<3 or MF-3, but International Prognostic Scoring System <high risk). In conclusion, our analysis suggests that better prognostication can be achieved in primary myelofibrosis patients when both systems are used together.

The Association Between JAK2V617F Mutation and Bone Marrow Fibrosis at Diagnosis in Patients with Philadelphia-Negative Chronic Myeloproliferative Neoplasms.

Objective: Bone marrow fibrosis is the second most common complication that causes morbidity and mortality inpatients with Philadelphia-negative myeloproliferative neoplasms (MPNs). The aim of this study was to investigate theassociation between JAK2V617F mutation and bone marrow fibrosis at diagnosis in patients with MPNs.Material and Methods: In total, 149 patients with MPNs were retrospectively evaluated to determine if there was anassociation between the histological grade of bone marrow fibrosis and JAK2V617F mutation.Results: In all, 67.7% of the patients carried the mutated JAK2 gene. The presence of JAK2V617F mutation was notassociated with the occurrence of bone marrow fibrosis (P=0.55) or its grade at diagnosis (P=0.65).Conclusion: Molecular mechanisms or genetic defects other than JAK2V617F may underlie the occurrence of bonemarrow fibrosis in patients with MPNs.

Prefibrotic Myelofibrosis (PreMF) Belongs to a Continuum of Epidemiological, Clinical and Histological Characteristics Featuring Primary Myelofibrosis (PMF)

Abstract 1743 Background:WHO diagnostic criteria of myeloproliferative neoplasms (MPNs) identify a preMF variant including patients having absence or early grade fibrosis, dual myeloid and megakaryocytic dominance, and clusters of atypical, ectopic, variable in size megakaryocytes in the bone marrow (BM). Many issues on the variant are critical, such as its distinction from essential thrombocythemia, recognisability, biological identity and true place among MPNs. Here we describe the clinical presentation of patients with preMF collected among a large cohort of patients diagnosed with PMF according WHO and for whom long-term follow-up data were available. The aim is to investigate whether there is an underlying structure of the patients' characteristics that allows to assign them to a distinct variant of MPNs or to align them along a continuum in the realm of PMF. Methods:We included in this study patients with PMF who were referred to the Center for the Study of Myelofibrosis of IRCCS Policlinico S. Matteo Foundation, Italy from 1990 to 2011. In all patients the BM biopsy taken at diagnosis was reviewed (pathologist: UM) and the diagnosis of preMF was established adopting the stringent criterion that, besides typical BM cellularity and megakaryocyte morphology, BM had less than grade 1 reticulin fibrosis (EUMNET criteria). Results:Of the 659 patients with PMF, 126 fulfilled the criteria we established for the diagnosis of preMF, thus accounting for 19.1% of the cohort. Female sex accounted for 59.5% of the preMF cohort while it accounted for 33.8% of PMF fibrotic type (P<0.0000). The mean age at diagnosis of patients with preMF was 39.2 years (range, 6 to 78 years), while it was 54.6, range 6 to 90 years (P<0.0000) in patients with PMF fibrosis type. Patients with preMF showed higher hemoglobin (14.0 vs. 11.9 g/dL; P=0.0004), higher platelet count (647 vs. 435 × 109/L; P<0.0000), lower WBC count (9.0 vs. 10.7 x109/L; P=0.02) and smaller spleen index (120 vs. 182; P<0.0000) than patients with MF fibrotic type. As a consequence, preMF displayed a greater frequency of patients with grade 0 IWG prognostic score ( 88.7% vs. 56.9%, P<0.0000). PreMF patients displayed a higher frequency of thrombotic events at the time of the diagnosis or in the year preceding the diagnosis (30.1% vs. 6.4%; P<0.0000). Both in prefibrotic and fibrotic type MF, the great majority of the thrombotic episodes were portal vein thrombosis or Budd-Chiari syndrome (89.4% in preMF and 79.4% in PMF fibrotic type). The proportion of JAK2 V617F mutated patients was not significantly different in the two categories of patients (65.2% vs. 62.1%; P=NS).In order to assign patients with PMF to groups with different degrees of BM fibrosis, we further categorized MF fibrotic type into early MF (BM fibrosis grade 1) and advanced MF (BM fibrosis grade 2 or 3). Female frequency steadily varied from 59.5% to 43.2% and 25.6% in the 3 categories of BM fibrosis, respectively. Age varied from 39.2, 50.4, 57.0 years, respectively. Hemoglobin and platelet count steadily decreased (Hb=14.0, 13.3, 11.2 g/dL, respectively; platelet count=647, 554, 346 x109/L, respectively). Spleen size steadily increased along with increasing of BM fibrosis (spleen index=120, 152, 200). All these parameters exhibited a statistically significant trend along the continuum of BM fibrosis grade (ANOVA, P<0.0001). During 993 cumulative person-years of follow-up, 4% of patients with preMF died. During 1372 cumulative person-years of follow-up, 15.4% of patients with early MF died. During 1446 cumulative person-years of follow-up, 24.5% of patients with advanced MF died. The cause of death was blast transformation in 80, 53 and 41.7% of cases, respectively. 94%, 80% and 54% of patients with preMF, early MF and advanced MF were alive at 10 years from the diagnosis. Overall, these results speak in favour to preMF belonging to a continuum of epidemiological, clinical and histological phenotypes in the realm of PMF. Splanchnic vein thrombosis, on the contrary, clusters in the category of preMF, suggesting that young age, female sex and a very indolent hematological phenotype are associated with biological characteristics that predispose to thrombosis. Conclusions:The BM picture of preMF identifies a group of patients with PMF associated with a very indolent hematologic phenotype, female dominance and very young age at presentation characterized by high incidence of splanchnic vein thrombosis. Disclosures:Barosi:Novartis: Membership on an entity's Board of Directors or advisory committees.

Phase I Study of the JAK2 V617F Inhibitor, LY2784544, in Patients with Myelofibrosis (MF), Polycythemia Vera (PV), and Essential Thrombocythemia (ET)

Abstract▪2814▪This icon denotes a clinically relevant abstract Background:The majority of primary and secondary MF, PV, and ET neoplasms are characterized by gain-of-function activation of JAK2 V617F/STAT5 signaling. Given that wild-type JAK2 plays a pivotal role in multiple stages of hematopoiesis it is desirable to treat JAK2 V617F-positive cases by selectively inhibiting JAK2 V617F while minimizing inhibition of wild-type JAK2 in order not to impede normal marrow function. In murine MPN models and in vitro cell based assays, a novel JAK2 inhibitor, LY2784544, demonstrates selective inhibition of JAK2 V617F/STAT5 signaling and mutant cell proliferation (Ma et al. Abstract 4087 ASH 2010). These results provided the basis for the LY2784544 Phase I trial in MF, PV, and ET patients (I3X-MC-JHTA, NCT01134120). Methods:The primary objectives are to determine the safety and tolerability of LY2784544 and define a recommended oral daily dose for further study in patients with JAK2 V617F-positive MF, ET, or PV. Secondary objectives include determination of pharmacokinetics and evaluation of response using the IWG-MRT response criteria, European Leukemia Net response criteria for PV and ET (EULN), and symptom burden using the Myeloproliferative Neoplasm Symptom Assessment Form (MPN-SAF) (Scherber et. al. Blood 2011). The study has a standard 3+3 dose-escalation design to define the maximum tolerated dose (MTD). The study was recently amended to allow cohort expansions at lower than MTD doses demonstrating potential clinical merit. Results:To date, 19 patients have been treated: 1 PV, 1 post-ET MF, and 17 MF patients. Four patients discontinued therapy, 1 for each of the following: Adverse Event, progressive disease, investigator decision, and subject's decision. Reported drug-related serious adverse events were seen in 4 patients, and include: creatinine increase (n=4 grade 2), hyperuricemia (2 grade 4), and hyperkalemia (1 grade 1). All resolved within 14 days with temporary treatment interruption. Analysis of collected laboratory studies using the definitions of Cairo and Bishop (BJH 2004, 2010) demonstrated that 1 instance of laboratory tumor lysis syndrome (LTLS) and 3 instances of Grade 2 clinical tumor lysis syndrome (CTLS) occurred. Hyperuricemia and creatinine increases in cases of TLS were reported as dose-limiting toxicities at 240 and 200 mg with 1 and 3 instances at each respective dose. The most frequently reported drug-related AEs across all grades were diarrhea (3 grade 2, 5 grade 1), nausea (3 grade 2, 4 grade 1), transient increased creatinine (4 grade 2), anemia (3 grade 2, 1 grade 1), and hyperuricemia (2 grade 4).A palpable spleen length reduction of at least 35% was seen in 13 of 17 evaluable patients (76% including 16 MF and 1PV). A partial response by EULN for PV involving 100% reduction in spleen size was observed for >10 months. In MF, 7 patients had a ≥50% reduction, including 4 with sufficient stability or duration of follow-up to qualify as a clinical improvement by IWG-MRT. After 5 cycles of therapy, a reduction in bone marrow fibrosis grade was observed in 3 of the 5 MF patients for whom follow-up biopsy results are available. Using the MPN-SAF questionnaire, patients reported improvements in symptom burden within the first 2 cycles of therapy. Fifty-nine percent (59%) reported a ≥50% improvement in the Key MPN Related Symptoms, and 47% reported a ≥50% improvement in the categories of Fatigue-Enjoyment of Life, Fatigue-Walking Ability, itching, and early satiety. A similar level of improvement was reported by 65% of patients for inactivity, while 35% had improvements in bone pain and night sweats. At tested doses, a reduction in mutant allele burden has not been observed. Conclusions:An MTD for daily dosing of LY2784544 was identified as 120 mg. Based on PK analysis, exposure from doses associated with TLS appear to overlap the lower boundary of the predicted biologically efficacious dose (BED) range established in murine JAK2 V617F models. To allow testing of doses within the BED, the dosing regimen has been amended to include a lower dose lead-in period, intended to reduce tumor burden, prior to further testing of dose escalation. This trial amendment will also further evaluate the bone marrow fibrosis response. Disclosures:Verstovsek:Eli Lilly: Research Funding. Off Label Use: Study of LY2784544 - Purpose is to present results of a study. Mesa:NS Pharma: Research Funding; Astra Zeneca: Research Funding; SBio: Research Funding; Lilly: Research Funding; Incyte: Research Funding; Celgene: Research Funding. Kloeker Rhoades:Eli Lilly: Employment, Equity Ownership. Giles:Eli Lilly: Employment, Equity Ownership. Pitou:Eli Lilly: Employment, Equity Ownership. Jones:Eli Lilly: Employment, Equity Ownership. Walgren:Eli Lilly: Employment, Equity Ownership.

Thrombosis History and Relationship with Low Thrombocytosis, Leukocytosis, and Jak2 V617F Mutation In A Cohort of 977 Patients with Essential Thrombocythemia (ET): Preliminary Report of the Registro Italiano Trombocitemia(RIT),

Abstract 3836▪▪This icon denotes a clinically relevant abstract Background.In essential thrombocythemia (ET) patients history of thrombosis and age over 60 y are validated risk factors for thrombosis; the thrombocytosis is a constitutive abnormality associated with both thrombotic and hemorrhagic risk; JAK2 V617F mutation, leukocytosis, and male gender are candidate thrombotic risk factors. Aims.To evaluate in ET patients clinical-biological characteristics at diagnosis and their relationship with thrombosis occurrence before and after diagnosis. Methods.A cohort of ET patients of the Registro Italiano Trombocitemia (RIT) was retrospectively analysed. This preliminary report in detail considers data on thrombosis history. Results.A total of 977 patients, 387 males and 590 females, presented at diagnosis: median age 55 y, median PLT count 783 × 109/L, median WBC count 8.8 × 109/L, median Hb 14.1 g/dL, bone marrow fibrosis (grade >0) in 33% of cases, history of thrombosis in 189 cases (19.3%). The patients at high risk (age over 60 y and/or history of thrombosis) were 511 (52 %). The thrombosis history in univariate analysis was significantly related to: age over 60 y (p 0.001), male gender (p 0.045), low thrombocytosis (PLT <783 x109/L, p 0.001), leukocytosis (WBC >8.8 x109/L, p 0.01), and JAK2 V617F mutation (p 0.006). No relationship was found with the bone marrow fibrosis.The 977 patients, when both PLT count and WBC count at diagnosis were considered, were subdivided in four groups: group 1: 202 pts with low thrombocytosis and leukocytosis; group 2: 270 pts with low thrombocytosis and no leukocytosis; group 3: 272 pts with high thrombocytosis and leukocytosis; group 4: 197 pts with high thrombocytosis and no leukocytosis. In those patients, the thrombosis history was: 26.7% in the group 1(both risk factors); 24.1% in the group 2 (PLT risk factor); 20.2% in the group 3 (WBC risk factor); 7.6% in the group 4 (no risk factors). The rate of thrombosis history in patients with one or two of these risk factors was significantly (p 0.001) higher than in patients with no risk factors. The thrombotic events during the follow up (4088 pt-y) are still object of analysis. Conclusion.In this cohort of ET patients the rate of thrombosis history in univariate analysis was related to age over 60 y. Moreover, a significant relationship was found with PLT count at diagnosis below the median value (783 x109/L), WBC count at diagnosis over the median value (8.8 x109/L), JAK2 V617F mutation, and male gender. Disclosures:No relevant conflicts of interest to declare.

Fibroproliferative activity in patients with immune thrombocytopenia (ITP) treated with thrombopoietic agents

This study assessed the grade of bone marrow (BM) fibrosis and its association with a seromarker for collagen-III formation and fibrosis-related cytokines in 25 immune thrombocytopenia (ITP) patients treated with thrombopoietin receptor agonists (Tpo-RA) who had at least one BM biopsy. Assessment of 8 pre- and on-treatment BM biopsies revealed statistically significant increases in reticulin. Reticulin in biopsies performed after a median of 1·4 years of treatment was graded: MF-0 in 3 (12%), MF-1 in 19 (76%), MF-2 in 2 (8%) and MF-3 in 1 (4%). No cytogenetic or flow-cytometric abnormalities were detected. Median pretreatment Procollagen III N-propeptide (PIIINP) (6·6 μg/l) was significantly higher than on-treatment levels (5·6 μg/l); both were higher than controls (3·4 μg/l; P < 0·001). PIIINP was negatively correlated with treatment duration (r = -0·49) suggesting a decelerated reticulin production over time. There was a trend towards an association between grade of reticulin and PIIINP. Transforming growth factor (GF)-beta and basic-Fibroblast GF were not different between patients and controls but Hepatocyte GF (HGF), an anti-fibrotic cytokine, was significantly elevated in patients. In conclusion, low-grade BM reticulin fibrosis is seen in most ITP patients on Tpo-RA. The novel findings of decreasing PIIINP and elevated HGF need further investigation to explore their significance in BM fibrogenesis.

Bone marrow reticulin and collagen content in patients with adult chronic immune thrombocytopenic purpura: A Danish nationwide study

We quantified and differentiated reticulin and collagen content in bone marrow specimens from chronic immune thrombocytopenic (ITP) patients and examined the correlation between some clinical characteristics and the fibrosis grading. Through the Danish National Patient Registry, we identified 378 patients with chronic ITP from 1997 until 2007. Of these, 253 (67%) had undergone at least one bone marrow biopsy, and we retrieved the bone marrow specimens from 187 (74%). We graded the bone marrow content of reticulin and collagen according to the Thiele scale (Grade 0-3). We also retrieved information on patients' clinical characteristics. We examined the prevalence of bone marrow fibrosis grading > 0 by patients' age (≤ 75 years and > 75 years), sex, platelet count at baseline (< 30 × 10⁹/L, and ≥ 30 × 10⁹/L), splenomegaly, hepatomegaly, and medications. In total 75 chronic ITP patients (40%) had a bone marrow grading >0. Of these, 72 (39%) had Grade 1 reticulin fibers present. Only three patients (< 2%) had collagen fibers present: two had Grade 2 and one had Grade 3. The prevalence of bone marrow grading > 0 was lower in patients aged > 75 years than ≤ 75 years (prevalence ratio = 0.64, 95% CI: 0.36-1.15) and lower in men than women (prevalence ratio = 0.70, 95% CI: 0.45-1.09), while a baseline platelet count ≥ 30 × 10⁹/L was associated with a higher prevalence of grading > 0 (prevalence ratio = 1.24, 95% CI: 0.81-1.86). Thus, bone marrow reticulin and collagen content in chronic ITP patients may be associated with some clinical characteristics.

Acute Panmyelosis with Myelofibrosis: Clinicopathological and Molecular Features of a Rare Malignant Bone Marrow Disease.

Abstract 3101Poster Board III-38 BackgroundAcute panmyelosis with myelofibrosis (APMF) is listed among the category of “AML, not otherwise specified” in the actual WHO classification of hematopoietic tumors. Since specific genetic alterations have not yet been defined, this myeloid neoplasm (MN) remains clinicopathologically assigned. The WHO classification addresses the difficulties concerning the differential diagnosis between APMF, myelodysplastic syndromes (MDS) with excess of blasts and concomitant fibrosis (RAEB-F) and acute megakaryoblastic leukaemia (AMGL). MethodsOur files were searched for patients with rapid-onset MN without a prior history of a myeloproliferative neoplasm or a MDS fulfilling the 2008 WHO criteria of APMF. An age- and gender-matched control group of RAEB-F cases with multilineage dysplasia was retrieved for comparison. Our approach included:i) the careful review of morphological, clinical and laboratory data with special regard to the proportion of immature CD34 + precursors/blasts in bone marrow (BM) biopsies; ii) the grading of BM fibrosis according to the European consensus guidelines; iii) the analysis of the JAK2-V617F, the MPL W515L and the GATA1 mutational status, the cytoplasmic localization of nucleophosphamin1 (NPM1) in BM blasts, and the expression the inhibitor of differentiation protein-2 (Id2) in hematopoietic and stroma cells; iv) the evaluation of the prognostic relevance of these parameters. ResultsFifty-four patients (32 males, 22 females) with a median age of 66, 9 years from our institutions were diagnosed APMF. Sufficient DNA for allele specific PCR for JAK2 genotyping was obtained from paraffin-embedded EDTA-decalcified BMB specimens from 22 APMF and 14 RAEB-F patients. In addition, an analysis of MPL W515L and GATA1 mutations was performed on 15 APMF cases. The relevant clinicopathological and molecular data are summarized in the table.APMFRAEB-FP valueMedianSurvival, median (months)0,0006,5 (*CI: 5,6-7,49)36,3 (CI: 0,9-71,7)MCV, mean (fl)<0,00190,29 (CI: 88,3-92,3)98,3 (CI: 95,2-101,3)LDH, mean ( U/l)<0,001401,8 (CI: 341,6-461,9258,3 (CI: 226,2-290,4)BM fibrosis, (grade)<0,0012,5 (CI: 2,4- 2,7)1,8 (CI: 1,6-2)BM Blasts (%)<0,00131,4 (CI: 27,2-35,5)13,3 (CI: 11,3-14,9)Aberrant NPM1 (%)n.s.12,97%JAK2V617 F + (%)n.s.36%21%MPL W515L +(%)0n.d.GATA1 + (%)0n.d.*CI: 95% confidence intervalSemiquantitative evaluation revealed a decreased expression level of Id2 in erythropoiesis of the APMF samples, while Id2 was increased in the stromal compartment. Within the total APMF cohort, patients aged ≤60 years had a longer OS (p=0,013). A comparison between the Kaplan-Meier curves of the APMF patients who underwent hematopietic cell transplantation (HCT) with those treated by conventional chemotherapy clearly showed that HCT significantly improved OS (median survival 6,1 vs. 11,1 months, p=0,005). Within the non-transplanted group, a bone marrow blast count ≤25% was associated with a longer OS (p=0,006). ConclusionsOur results point to significant differences between APMF and RAEB-F with regard to OS, MCV, LDH, BM fibrosis and BM blast cells. We detected a higher frequency of mutated JAK2 V616F in the MB samples than generally reported in the literature for other categories of AML or MDS. However, the JAK2 V617F mutation status or an aberrant cytoplasmic NPM1 localization were both not predictive of outcome. In contrast to data published for AMGL, no association between a MPL W515L mutation and APMF was observed. Survival was significantly worse in APMF than in RAEB-F. A rapid diagnosis based on a multiparameter approach and a proper management including the option of HCT even in elderly patients seems mandatory for APMF patients. Targeting the fibrotic BM microenvironment which is characterized by an increased Id2 expression may be considered for future therapeutic strategies. DisclosuresSkoda:Genentech Inc.: Consultancy.

Myelofibrotic transformation in essential thrombocythemia

The exact incidence of myelofibrotic transformation in essential thrombocythemia (ET) is still a critical issue1,2 and is certainly influenced by risk status and diagnostic criteria. In a recently published study by Passamonti and co-workers in this journal,3 a cohort of 605 patients with ET is described recruited during a lengthy period (1975 to 2008) from one center. Unfortunately, as explicitly stated, diagnosis of ET was performed using criteria at the time of the first observation, implicating that a large fraction, probably the majority of patients, were diagnosed by following the cited criteria of the Polycythemia Vera Study Group (PVSG),4 contrasting the more recently entered fraction to whom the WHO classification was applied.5 Consequently, the diagnostic guidelines are inconsistent regarding a strict differentiation of ET from early stages of primary myelofibrosis (PMF) with associated thrombocytosis. It has been demonstrated by different groups that significant differences exist between the PVSG versus the WHO classification schemes for ET: depending on risk factors and selection of patients only about 20–40% of ET cases diagnosed according to the PVSG4 are validated by the WHO criteria.6–8 The diagnosis of post-ET myelofibrosis was made by the authors using the criteria of the International Working Group on Myelofibrosis (IWG-MRT).9 However, these criteria do explicitly include as first major requirement the documentation of a previous diagnosis of WHO-defined essential thrombocythemia . This postulate can not be fulfilled by the obviously predominant PVSG-diagnosed series of patients incorporated into this investigation. Moreover, following the IWG-MRT criteria, bone marrow fibrosis grade 2–3 consistent with the cited European Consensus Grading System10 is the second major requirement. This important feature implicates the evaluation of sequential bone marrow biopsy specimens - has this been performed in all patients under study? Concerning the frequency of post-ET myelofibrosis, the transformation rate was 2.8% at a median follow-up of 9.1 years (or a 10-year risk of 3.9% and a 15-year risk of 6%).3 This relatively low incidence may possibly be created by including an unknown number of WHO-diagnosed ET cases into this study. When strictly following the diagnostic criteria of the PVSG4 applied in the UK-PT1 Study for high risk ET,11 in our retrospective evaluation of 539 patients under standard therapy, after three years overall incidence of myelofibrosis proved to be significantly different depending on diagnostic criteria (Table 1). Table 1. Risk of myelofibrotic transformation (post-essential thrombocythemia myelofibrosis) within 36 months in 539 high-risk patients with essential thrombocythemia strictly diagnosed according to the UK-PT1 Study criteria11 receiving standard therapy regimens. ... This difference was generated by discrimination of the total cohort according to the WHO classification5 into (true) ET and PMF with accompanying thrombocytosis mimicking this condition. On the other hand, when maintaining the PVSG guidelines,4 a comparable rate (2.8% vs. 2.6%)11 of progression into myelofibrosis was revealed during an observation time of about three years. Regarding leukemic transformation, although no systemic study has yet been published, similar discrepancies associated with applied classification schemes may be encountered. In conclusion, a thorough re-evaluation of this series of 605 patients with distinction into those diagnosed as ET cases according to PVSG criteria4 versus those in whom diagnosis was based on the WHO classification seems to be warranted, including a repeatedly performed calculation of progression rates into myelofibrosis and leukemia. As criteria for myelofibrotic transformation, the corresponding guidelines of the UK-PT1 Study11 should be used for the presumably prevalent ET group diagnosed after PVSG, and for the WHO classified series the IWG-MRT parameters can be applied. As has been reviewed for myelofibrosis in chronic myeloproliferative neoplasms,12 a significant difference between both groups of patients can be predicted consistent with the diagnostic criteria applied.

Prognostic implications of the European consensus for grading of bone marrow fibrosis in chronic idiopathic myelofibrosis

Various clinical prognostic scoring systems (PSSs) have been suggested as means of selecting high-risk chronic idiopathic myelofibrosis (CIMF) patients at diagnosis. The WHO has recently proposed strict diagnostic criteria for CIMF, and the European consensus for bone marrow fibrosis (BMF) grading recommends 4 classes. It has been suggested that BMF grading may play a prognostic role in CIMF, but it has never been compared with the other PSSs in the same patients. We tested a prognostic model for overall survival (OS) based on the WHO criteria and BMF grading in 113 consecutive patients with chronic myeloproliferative disorders (98 with CIMF and 15 with postpolycythemic myelofibrosis), and compared the findings with those of PSSs. The results showed that our model is significantly associated with different OSs and, unlike the other PSSs, clearly discriminates the OS of intermediate- and high-risk patients.