post-PV Myelofibrosis Research Articles

Long-Term Efficacy and Safety in COMFORT-II, a Phase 3 Study Comparing Ruxolitinib with Best Available Therapy for the Treatment of Myelofibrosis: 5-Year Final Study Results

Long-Term Efficacy and Safety in COMFORT-II, a Phase 3 Study Comparing Ruxolitinib with Best Available Therapy for the Treatment of Myelofibrosis: 5-Year Final Study Results

Safety and Efficacy of Combination Therapy of Interferon-Alpha2 + JAK1-2 Inhibitor in the Philadelphia-Negative Chronic Myeloproliferative Neoplasms. Preliminary Results from the Danish Combi-Trial - an Open Label, Single Arm, Non-Randomized Multicenter Phase II Study

Safety and Efficacy of Combination Therapy of Interferon-Alpha2 + JAK1-2 Inhibitor in the Philadelphia-Negative Chronic Myeloproliferative Neoplasms. Preliminary Results from the Danish Combi-Trial - an Open Label, Single Arm, Non-Randomized Multicenter Phase II Study

Impact of Disease Duration upon Symptom Burden Amongst Patients with Myeloproliferative Neoplasms (MPNs)

Background: The Philadelphia chromosome negative myeloproliferative neoplasms (MPNs), including essential thrombocythemia (ET), polycythemia vera (PV) and myelofibrosis (MF) all have a time dependent risk of progression to either an advanced myelofibrotic state (post ET/PV MF) and/or to acute myeloid leukemia. The impact of disease duration upon the MPN symptom burden is not well understood, nor are the precise mechanisms of disease progression. We sought to better understand the impact of disease duration on MPN symptom burden.Methods:Symptom burden data was collected utilizing the Myeloproliferative Neoplasm Symptom Assessment Form (MPN-SAF) amongst MPN patients, collected at the time of an office visit in an international cohort of MPN patients as previously described (Scherber et. al.). Symptom burden assessment was a previously validated 27-item symptom burden questionnaire scored on a 0-10 scale (0= as good as it can be, 10 = as bad as it could be). The patient or provider was asked to report the time since MPN diagnosis. MPN duration was determined to be early if the diagnosis was established between 0 to 5 years ago, intermediate if the diagnosis was established between 6 to 10 years ago, and late if the diagnosis was established 11 years ago or more. Anemia was defined as a red blood cell count less than 10 g/dL, leukopenia was defined as a white blood cell count was below 4 x 109, and thrombocytopenia if the platelet count was below 150 x109. Statistical significance was calculated using ANOVA f-test and chi squared.Results:Patient demographics and disease burden: A total of 1443 patients responded to the survey, including 592 (41%) ET, 549 (38%) PV, and 302 (21%) MF patients, including 181 (60%) primary MF, 67 (22%) post-ET MF, and 54 (18%) post-PV MF. Among MF patients, mean duration of MPN diagnosis was 9 years, and mean duration MF diagnosis was 4.7 years. Among respondents, 757 fit criteria for early disease duration, 353 fit criteria for intermediate disease duration, and 333 fit criteria for late disease duration. Respondent mean age was 62 years and approximately half of respondents were female (55%). Patients with longer diagnosis duration tended to be older (p=0.009) and were most likely to have anemia (0.02), leukopenia (p=0.01), or thrombocytopenia (p=0.03). These individuals were also most likely to have a history of hemorrhage (p=0.007) or require red blood cell transfusions (p<0.001).Combined cohort symptom burden: On average among the combined cohort of ET, PV and MF patients, symptoms tended to worsen with time with this effect being significant for symptom items of fatigue (BFI, p<0.04), concentration (p=0.007), insomnia (p=0.02), sexual difficulties (p=0.002), cough (p=0.03), night sweats (p=0.002), and pruritus (p=0.02). Symptoms of early satiety (p=0.004), concentration difficulties (p=0.01), insomnia (p=0.03), sexual difficulties (p=0.02), cough (p=0.01), and night sweats (p=<0.001) had significantly higher prevalence in those with longer disease duration. Similarly, the total calculated MPN-10 score (p=0.008) and quality of life assessment (0.03) demonstrated worsened outcomes with time (Table 1). No significant differences in symptoms for the combined cohort were observed among individuals diagnosed 0 to 1 years ago compared to those with a diagnosis established between 2 and 5 years ago.Symptom burden in MPN subtypes. When evaluating specific MPN types, patients with essential thrombocythemia experienced significantly greater sexual difficulties over time (p=0.03). The severity (p=0.01) and incidence (p=0.03) of pruritus and incidence of night sweats (p<0.001) were significantly increased over time for individuals with PV. For those with MF, the severity (p= 0.01) and incidence (p=0.009) of cough also significantly increased with longer diagnosis duration.DiscussionOverall, significant worsening in symptom burden can be recognized over time for individuals diagnosed with MPNs. Diagnosis may not necessarily correlate with disease duration as the timing of diagnosis may be delayed from onset of disease. Given the intent of this abstract to evaluate changes with disease duration, we did not investigate correlations between symptom burden and cytopenias. We do know that risk factors for survival in the MPNs include older age and thrombosis, however, disease duration should be investigated as an alternative marker of burden in future survival studies. [Display omitted] DisclosuresHarrison:CTI Biopharma: Consultancy, Honoraria, Speakers Bureau; Shire: Speakers Bureau; Gilead: Honoraria; Novartis: Honoraria, Research Funding, Speakers Bureau; Sanofi: Honoraria, Speakers Bureau. Kiladjian:Incyte Corporation: Consultancy; Novartis: Other: Travel grant; Research Funding paid to institution (Hôpital Saint-Louis et Université Paris Diderot); Novartis: Consultancy. Zweegman:Celgene: Research Funding; Janssen: Research Funding; Takeda: Research Funding. Barbui:Novartis: Speakers Bureau. Etienne:Novartis: Consultancy, Honoraria, Other: Congress Travel/Accomodations, Research Funding, Speakers Bureau; BMS: Consultancy, Honoraria, Speakers Bureau; ARIAD: Consultancy, Honoraria, Speakers Bureau. te Boekhorst:CTI Biopharma: Consultancy; Novartis: Consultancy. Vannucchi:Novartis: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Novartis: Other: Research Funding paid to institution (University of Florence), Research Funding; Shire: Speakers Bureau; Baxalta: Membership on an entity's Board of Directors or advisory committees. Mesa:Novartis. Research- incyte, Gilead, cti, Genentech, promedior, NS Pharma: Consultancy.

Leukocytosis Can Predict Thrombotic Events in Myelofibrosis

Thrombotic events are the main complication of Philadelphia-negative chronic myeloproliferative neoplasms (MPN). In polycythemia vera (PV) and essential thrombocythemia (ET), risk factors for thrombosis are well established, such as age greater than 60 years and previous thrombosis. However, the role of JAK2 V617F mutation and leukocytosis at diagnosis as risk factor for thrombosis is still controversial. Our aim was to identify factors related to the risk for thrombotic events in the studied population.This study is a retrospective non-interventional cohort. All of the analyses were performed using the database of 142 patients with MPN regularly followed at the Hematology Division (at UNIFESP-SP) from 1992 to 2014. Diagnosis was established according to WHO criteria. We analyzed the JAK2 V617F mutation, hemoglobin (g/dL), hematocrit (%), white blood cells (x109/L) and platelets (x109/L) at the diagnosis and DIPSS-Plus risk score (International Working Group for Myelofibrosis Research and Treatment, 2009). These variables were associated with thrombotic event at any time.Of the 142 patients, 54 had diagnosis of PMF, 28 of PV, 33 of ET and 27 of post-essential thrombocythaemic myelofibrosis (post ET MF) or post-polycythaemic myelofibrosis (post-PV MF). This last group was included in myelofibrosis group for statistical purposes.Thrombotic events were more frequent in PV patients (39.2%), followed by ET (33.3%), and PMF (20.9%).From those which JAK2 mutation was obtained, it was positive in 92.4% of PV patients, 62% of PMF and 50% of ET. In none of the three groups, the presence of JAK2 V617F mutation was related to increased risk of thrombosis.In myelofibrosis, leukocytosis was higher among thrombotic patients (median of 13.7 in thrombotic group versus 9.7x 109/L; p 0.0379). None of the other parameters, hemoglobin, hematocrit, platelets and DIPSS-Plus were statistically significant. In ET, the hemoglobin level at diagnosis was significantly higher in the presence of thrombosis (mean of 14.57 in thrombotic group against 13.03 g/dL in the non-thrombotic one, p 0.0428). The other parameters, hematocrit, white blood cells and platelets were not relevant. The median WBC in the thrombotic group was 9.4 and in the non-thrombotic one 9.3 x109/L. Finally, in polycythemia vera, none of the variables were related to thrombosis. Among the studied population, leukocytosis was increased in patients with thrombotic event in MF. Thus, monitoring leukocyte count in MF is essential to predict thrombosis risk and should be further studied in order to define therapeutic goals in these patients. DisclosuresNo relevant conflicts of interest to declare.

A Phase-Ib/II Study of Ruxolitinib Plus Pomalidomide in Myelofibrosis

Background: Myelofibrosis (MF) patients (pts) frequently suffer from constitutional symptoms, splenomegaly, and cytopenia. While ruxolitinib (RUX) is available for the treatment of symptomatic splenomegaly and constitutional symptoms in MF, therapeutic options for the treatment of cytopenia are limited. Recent data indicate that the immunomodulatory drug pomalidomide (POM) may improve anemia and thrombocytopenia in a subset of MF pts (e.g. Tefferi et al., J Clin Oncol 2009). We designed a single arm, multicenter phase-Ib/II combination study of RUX and POM (MPNSG-0212 trial, NCT01644110) to evaluate potential synergistic effects of both drugs in MF.Study Design: Primary endpoints are response rate after 12 treatment cycles (28 days each) according to IWG-MRT criteria (Tefferi et al., Blood 2006) and achievement of red blood cell (RBC) transfusion independence (Gale et al., Leuk Res 2011). Secondary endpoints are safety, quality of life, progression-free survival, and overall survival. Main inclusion criterion is pre-treated or untreated primary or secondary (post-ET / post-PV) MF with anemia (Hb <10 g/dL and/or RBC transfusion dependency). Key exclusion criteria are suitability for allotransplant, low platelet count (<100 /nL), and severe neutropenia (ANC <0.5 /nL). While POM is given at the fixed dosage of 0.5 mg QD, RUX is started at 10 mg BID with dose modifications being allowed to optimize efficacy and to manage myelosuppression. According to a Simon´s two-stage design, recruitment will be extended to a total number of 72 pts if response is achieved in a minimum of 12/37 pts tested initially.Results: Safety of the combination therapy was evaluated favorably by an independent safety monitoring committee after treatment of the first 6 pts as reported previously (Stegelmann et al, ASH 2014). Here, we present follow-up data from 25 pts. Median age of the study population was 75 years (range 51-82). Ten of 25 pts (40%) had one or more previous therapies. The most frequent previous drugs were hydroxyurea (n=6), ruxolitinib (n=3), EPO (n=2), pomalidomide (n=2), and steroids (n=2). Median Hb at study entry was 8.6 g/dL (range 6.8-10.6); 6 pts (24%) were RBC transfusion dependent. Median spleen size measured by ultrasound was 18 cm (range 13-28). Eight pts (32%) were intermediate-1, 10 pts (40%) intermediate-2, and 7 pts (28%) high-risk according to the dynamic international prognostic scoring system (DIPSS). Mutation frequencies of JAK2 V617F, MPL W515L, and CALR exon 9 were 72%, 12%, and 16%, respectively. ASXL1 was mutated in 5 pts (20%). Regarding safety, 287 adverse events (AE) of any grade (CTCAE 1-5) were recorded. Among these, worsening of anemia (°3/°4) was the most frequent AE (n=35 in 9 pts), followed by musculoskeletal pain (n=25 in 6 pts; °1-°3), and constitutional symptoms (n=13 in 2 pts; °1-°3). In total, 11 serious AE (SAE) CTCAE °2-5 were recorded. While 9 SAE (pneumonia °3, n=3; cardiac decompensation °5, malignant melanoma °2, septic shock °5, syncope °3, and TIA °2, worsening of general condition °3, n=1 each) were considered non-related to the study drugs, 2 SAE (hemoglobin °4, neuropathy °3) were considered related. Of note, neuropathy resolved after end of study. Treatment interruptions and dose reductions of RUX were uncommon. RUX could be step-wise increased to 15 or 20 mg BID in 10 pts (40%). Median time on treatment was 8 28-days cycles (range 1-13) in 24 pts, while one patient has not yet started therapy; 14 pts (56%) are still on study treatment. A total of 10 pts (40%) discontinued, due to death (n=2), no response after 12 cycles (n=5), or withdrawal of informed consent (n=3). Within this short observation time, 3 pts experienced ´clinical improvement´ (CI) according to IWG-MRT criteria in the following categories: i) spleen reduction, ii) spleen reduction + increase of Hb, and iii) increase of both Hb and ANC. RBC transfusion independency criteria have not yet been fulfilled in transfusion dependent pts. None of the study pts progressed during treatment.Conclusions: Taking into account that the majority of study pts were pre-treated and at advanced risk, the combination therapy of RUX and POM was well tolerated and is feasible. First efficacy evaluation shows that clinical improvement regarding reduction of splenomegaly and improvement of cytopenia is achieved in a subset of MF pts. Recruitment of the study continues. An update on safety and efficacy will be presented at the meeting. DisclosuresHochhaus:ARIAD: Honoraria, Research Funding; Bristol-Myers Squibb: Honoraria, Research Funding; Pfizer: Honoraria, Research Funding; Novartis: Honoraria, Research Funding. Scheid:Celgene: Honoraria, Membership on an entity's Board of Directors or advisory committees; Janssen-Cilag: Honoraria, Membership on an entity's Board of Directors or advisory committees. Schlenk:Arog: Honoraria, Research Funding; Daiichi Sankyo: Membership on an entity's Board of Directors or advisory committees; Boehringer-Ingelheim: Honoraria; Pfizer: Honoraria, Research Funding; Novartis: Honoraria, Research Funding; Teva: Honoraria, Research Funding; Janssen: Membership on an entity's Board of Directors or advisory committees.

Poor Correlation Between DIPSS and Passamonti Prognostic Risk Scores for Post Polycythemia Vera and Essential Thrombocythemia Myelofibrosis

Background: Post polycythemia vera (PV) and essential thrombocytosis (ET) myelofibrosis (MF), like primary MF (PMF), are heralded by splenomegaly, cytopenias, heavy symptom burden, and decreased overall survival. Risk prognostication tools, including the dynamic international prognostic scoring system (DIPSS) and the Passamonti risk score for post-PV MF (Passamonti et al. Blood 2010, 2008), are helpful to estimate survival and guide therapeutic decision-making. For Post-PV/ET MF, it is unknown if DIPSS correlates with the Passamonti risk score. Here we evaluate the correlation between the two available risk prognostication tools in post-PV/ET MF.Methods:Retrospective chart review conducted for patients with post-PV/ET MF seen between 2000-2012. Descriptive statistics were used to describe patient demographic and clinical variables in post PV/ET patients.DIPSS Score: calculated at time of last follow up: 1 point for age >65, 2 points for hemoglobin <10g/dL, 1 point for leukocytes >25 x 109, 1 point for circulating blasts 1% and 1 point for constitutional symptoms. Risk group was assigned: low-risk (0 adverse points), intermediate-1 risk (1 adverse point), intermediate-2 risk (2-3 adverse points) and high-risk (4-6 adverse points).Passamonti Risk Scores: calculated at time of last follow up: with 1 point assigned for hemoglobin level less than 100 g/L (10 g/dL), platelet count less than 100 x10 (9)/L, and/or leukocyte count more than 30x10(9)/L.Cross-tabulation of DIPSS score versus Passamonti risk score at time of last follow-up was conducted and the percent agreement was described. Spearman correlation coefficient between DIPSS score at follow-up with Passamonti score was conducted.Results:Patients:Sixty-one (58%) post-ET and 44 (42%) post-PV patients were identified, total N=105. Male to Female ratio was 1:1. Median age was 65 (range 25-87). JAK2 V617Fpresent in 68 (65.4%). Median hemoglobin was 10.9 g/dL (range 5.3-17.0), median platelet count 287 x 109 (range 20-1864), and median WBC was 11.1x 109 (range 1.1-165).Risk prognostication:When DIPSS risk scores were applied 11 patients were low, 48 patients were Intermediate-1, 31 patients were Intermediate-2, and 10 patients were high. When Passamonti risk scores were applied 57 patients received score of 0, 31 patients scored 1, 9 patients scored 2, and 3 patients scored 3.DIPSS and Passamonti risk score agreement:The overall agreement between DIPSS and Passamonti risk scores was low, with 24% of cases in agreement. Spearman correlation: Rho=0.451; p<0.001. See Table #1 with agreement seen in highlighted cells.Table 1DIPSS and Passamonti AgreementPassamonti Risk ScoreDIPSS0123TotalLow9 (75%)3 (25%)0012Int-131 (77.5%)8 (20%)1 (2.5%)040Int-217 (43.6%)14 (35.9%)6 (15.4%)2 (5.1%)39High06 (75%)1 (12.5%)1 (12.5%)8Total57 (57.6%)31 (31.3%)8 (8%)3 (3%)100Conclusion:Post PV/ET MF represents a unique clinical entity and risk prognostication schemes developed for PMF, such as DIPSS, may not represent accurate prognosis estimation in this subgroup of MF. When DIPSS and Passamonti risk scores were applied to same post PV/ET group, agreement was poor at 24%. Additionally, DIPSS was more likely to assign patients to high-risk category than Passamonti. Further studies are needed to evaluate the DIPSS and Passamonti prognostic risk score application to the post PV/ET MF population. DisclosuresMesa:Incyte Corporation: Research Funding; Pfizer: Research Funding; NS Pharma: Research Funding; Promedior: Research Funding; Incyte Corporation: Research Funding; Gilead: Research Funding; Novartis Pharmaceuticals Corporation: Consultancy; Genentech: Research Funding; Promedior: Research Funding; CTI Biopharma: Research Funding; Novartis Pharmaceuticals Corporation: Consultancy; CTI Biopharma: Research Funding; Genentech: Research Funding; Gilead: Research Funding; Pfizer: Research Funding; NS Pharma: Research Funding.

Incidence and risk factors for myelofibrotic transformation among 272 Chinese patients with JAK2-mutated polycythemia vera.

Post-polycythemia vera myelofibrosis (post-PV MF) is a critical hematologic evolution of polycythemia vera (PV). The main purpose of the present study was to identify the possible risk factors for the occurrence and prognosis of post-PV MF in Chinese patients with PV. A cohort of 272 Chinese PV patients with JAK2(V617F) or exon12 mutation was retrospectively analyzed. Of the 272 patients with PV, 63 developed post-PV MF. Platelet count >550 × 10(9) /L and splenomegaly were identified as independent risk factors for post-PV MF. The median duration of survival for post-PV MF patients was 8 years. Anemia and age >65 years at diagnosis of post-PV MF were identified as significant predictors for the poor prognosis of post-PV MF. In conclusion, platelet counts and splenomegaly were significant predictors for the transformation to post-PV MF, while anemia (hemoglobin levels <100 g/L) and age>65 years were significant predictors for poor prognosis of post-PV MF in Chinese PV patients with JAK2(V617F) or exon12 mutation.

Blast transformation and fibrotic progression in polycythemia vera and essential thrombocythemia: a literature review of incidence and risk factors.

Polycythemia vera (PV) and essential thrombocythemia (ET) constitute two of the three BCR-ABL1-negative myeloproliferative neoplasms and are characterized by relatively long median survivals (approximately 14 and 20 years, respectively). Potentially fatal disease complications in PV and ET include disease transformation into myelofibrosis (MF) or acute myeloid leukemia (AML). The range of reported frequencies for post-PV MF were 4.9–6% at 10 years and 6–14% at 15 years and for post-ET MF were 0.8–4.9% at 10 years and 4–11% at 15 years. The corresponding figures for post-PV AML were 2.3–14.4% at 10 years and 5.5–18.7% at 15 years and for post-ET AML were 0.7–3% at 10 years and 2.1–5.3% at 15 years. Risk factors cited for post-PV MF include advanced age, leukocytosis, reticulin fibrosis, splenomegaly and JAK2V617F allele burden and for post-ET MF include advanced age, leukocytosis, anemia, reticulin fibrosis, absence of JAK2V617F, use of anagrelide and presence of ASXL1 mutation. Risk factors for post-PV AML include advanced age, leukocytosis, reticulin fibrosis, splenomegaly, abnormal karyotype, TP53 or RUNX1 mutations as well as use of pipobroman, radiophosphorus (P32) and busulfan and for post-ET AML include advanced age, leukocytosis, anemia, extreme thrombocytosis, thrombosis, reticulin fibrosis, TP53 or RUNX1 mutations. It is important to note that some of the aforementioned incidence figures and risk factor determinations are probably inaccurate and at times conflicting because of the retrospective nature of studies and the inadvertent labeling, in some studies, of patients with prefibrotic primary MF or ‘masked' PV, as ET. Ultimately, transformation of MPN leads to poor outcomes and management remains challenging. Further understanding of the molecular events leading to disease transformation is being investigated.

The effect of long-term ruxolitinib treatment on JAK2p.V617F allele burden in patients with myelofibrosis

AbstractThe JAK2 c.1849G>T (p.V617F) mutation leads to constitutive activation of Janus kinase (JAK)2 and contributes to dysregulated JAK signaling in myelofibrosis (MF), polycythemia vera (PV), and essential thrombocythemia (ET). In the phase 3 Controlled Myelofibrosis Study with Oral JAK Inhibitor Treatment-I trial, patients with MF, post-PV MF, or post-ET MF achieved significant reductions in splenomegaly and improvements in symptoms with ruxolitinib vs placebo at week 24. This long-term follow-up analysis was performed to determine whether ruxolitinib therapy altered the JAK2p.V617F allele burden in JAK2p.V617F-positive patients. Assessments at baseline and weeks 24, 48, 120, 144, 168, and 216 demonstrated reductions in allele burden from baseline with ruxolitinib treatment that correlated with spleen volume reductions. Of 236 JAK2p.V617F-positive patients analyzed, 20 achieved partial and 6 achieved complete molecular responses, with median times to response of 22.2 and 27.5 months, respectively. Allele burden reductions were greater in patients with shorter disease duration, which suggests a potential benefit of earlier treatment. This trial was registered at www.clinicaltrials.gov as #NCT00952289.

Phase 1/2, dose-escalation study of oral NS-018 in patients with primary myelofibrosis (PMF), post-polycythemia vera MF (post-PV MF), or post-essential thrombocythemia MF(post-ET MF)

S58 63.4% intermediate-1 63.4%, intermediate-2 28.1% and none high risk. Anemia was the most frequent laboratorial finding (67%) and most of the patients were treated with hydroxiurea (75.7%). Conclusions: Although most of the patients have apparently the diagnosis of PMF, it took almost 10 months to be done. An expressive number of medical reports do not show a complete history, while 2030% of them don’t have all the laboratory tools for a precise diagnosis. It is important to know Brazilian needs to improve diagnostic and provide a better treatment, since we are facing new drugs for PMF.

Outcomes in Myelofibrosis Patients Completing 24 and 36 Weeks of Treatment with PRM-151

S58 63.4% intermediate-1 63.4%, intermediate-2 28.1% and none high risk. Anemia was the most frequent laboratorial finding (67%) and most of the patients were treated with hydroxiurea (75.7%). Conclusions: Although most of the patients have apparently the diagnosis of PMF, it took almost 10 months to be done. An expressive number of medical reports do not show a complete history, while 2030% of them don’t have all the laboratory tools for a precise diagnosis. It is important to know Brazilian needs to improve diagnostic and provide a better treatment, since we are facing new drugs for PMF. 806 Phase 1/2, dose-escalation study of oral NS-018 in patients with primary myelofibrosis (PMF), post-polycythemia vera MF (post-PV MF), or post-essential thrombocythemia MF(post-ET MF) Efficacy Parameter 24 weeks 36 weeks Patients with BM fibrosis reduction 1 grade 35% 50% Patients with BM fibrosis reduction by CIA 58% 90% Symptom Response 25% 27% % Change in spleen size -6% -16%

Research progress of JAK1/2 inhibitors in the treatment of myeloproliferative neoplasms

The bcr-abl negative myeloproliferative neoplasms (MPN) include polycythemia vera (PV), essential thrombocythemia (ET) and primary myelofibrosis (PMF). Along with the detecting of JAK2 V617F gene mutation in MPN patients, a series of small molecules drugs that targeted to the mutation have been investigated in clinical trials. Ruxolitinib is the inhibitor of JAK1/2, which has been proved by USA Food and Drug Administration (FDA) and the European Medicines Agency (EMA) to treat patients with intermediate-2 or high-risk PMF or post-PV MF or post-ET MF and PV patients who are intolerant or resistant to hydroxycarbamide, attributed to a number of clinical trials, especially in COMFORT-Ⅰ and COMFORT-Ⅱ. As a result, the MPN patients have new hope for the treatment. Key words: Myeloproliferative neoplasms; Polycythemia vera; Primary myelofibrosis; Ruxolitinib

JAK2 inhibition has different therapeutic effects according to myeloproliferative neoplasm development in mice.

JAK2 inhibition therapy is used to treat patients suffering from myeloproliferative neoplasms (MPN). Conflicting data on this therapy are reported possibly linked to the types of inhibitors or disease type. Therefore, we decided to compare in mice the effect of a JAK2 inhibitor, Fedratinib, in MPN models of increasing severity: polycythemia vera (PV), post-PV myelofibrosis (PPMF) and rapid post-essential thrombocythemia MF (PTMF). The models were generated through JAK2 activation by the JAK2V617F mutation or MPL constant stimulation. JAK2 inhibition induced a correction of splenomegaly, leucocytosis and microcytosis in all three MPN models. However, the effects on fibrosis, osteosclerosis, granulocytosis, erythropoiesis or platelet counts varied according to the disease severity stage. Strikingly, complete blockade of fibrosis and osteosclerosis was observed in the PPMF model, linked to correction of MK hyper/dysplasia, but not in the PTMF model, suggesting that MF development may also become JAK2-independent. Interestingly, we originally found a decreased in the JAK2V617F allele burden in progenitor cells from the spleen but not in other cell types. Overall, this study shows that JAK2 inhibition has different effects according to disease phenotypes and can (i) normalize platelet counts, (ii) prevent the development of marrow fibrosis/osteosclerosis at an early stage and (iii) reduce splenomegaly through blockage of stem cell mobilization in the spleen.

Unusual ROS1 Translocation Pattern in a 61 Year-old Woman with Metastatic Adenocarcinoma of Lung

s 363 Brazil. The use of the array CGH (aCGH) has aided significantly the genetic diagnosis in recent years. In our laboratory aCGH combined with conventional karyotyping allowed an improvement of 20% to 30% in the diagnostic rate of patients with intellectual disabillity, dysmorphisms, autism and developmental delay. We used the Affymetrix chip Cytoscan HD and 750 K Cytoscan arrays (Santa Clara, CA) and analysis through the respective software system and for conventional karyotype (G Banding). We selected 2 cases to report: Case 1: Two siblings with distinct developmental disturbance phenotypes. Sibling one is a 7-year-old female with severe developmental delay phenotype, microcephaly and consanguineous parents. She presented an interstitial deletion of 12,1 Mb on chromosome 5, arr [hg19] 5p14.3p15.31 (6,801,589-18,992,827) 1, featuring the Cri-du-chat syndrome. Her brother, a 12-year-old male with mild intellectual disability (ID) a duplication of the exact same size and region that was deleted in the sister was found arr [hg19] 5p14.3-p15.31 (6,801,589-18,992,827) 3. Parental aCGH was normal. However, conventional karyotype of the father revealed 2 reciprocal translocation between chromosomes 1 and 2, 5 and 7: (46, XY, t(1, 2) (q44;w p23pter) t(5; 7)(p14.3-p15.31; p22). Case 2: A 16-year-old female with consanguineous parents and normal conventional karyotyping. She presents significant developmental delay, dyslalia, severe ID, autistic traits, irritability, hyperactivity and autoagression, without obvious dysmorphias and with normal: MRI, electroencephalogram and CT scan results. Microarray analysis revealed a homozygous microdeletion of 197 Kbp on chromosome 8:arr [hg19] 8p22 (15,451,748-15,649,733) 1, spanning almost the entire TUSC3 gene, except promoter and first exon (601385*).This is the seventh family with a reported TUSC3 mutation with mostly non syndromic ID and the second with the same deletion (Khan et al, 2011). Three of the families reported in the literature carried a deletion which encompassed only the TUSC3 promoter region and the first exon, 2 families presented distinct point mutations and 1 an intragenic duplication. All 7 families presented homozygous mutations, only 1 was not consanguineous however they were from the same village. Conclusion: These cases illustrate the importance of integrating conventional karyotyping techniques and microarray in genetic diagnosis. Both cases were referred for genetic counselling and family research. Unusual ROS1 Translocation Pattern in a 61 Year-old Woman with Metastatic Adenocarcinoma of Lung Hui Chen , Rajyalakshmi Luthra , Neda Kalhor , John Heymach , Ronald Abraham , Meenakshi Mehrotra , Bal Mukund Mishra , Keyur P. Patel , Rajesh R. Singh , Xinyan Lu b Department of Pathology, MD Anderson Cancer Center, Houston, TX, USA; Department of Hematopathology, MD Anderson Cancer Center, Houston, TX, USA; Department of Thoracic/Head N b Georgia Cancer Specialists and Northside Hospital Cancer Institute, Atlanta, GA, USA Recent studies show that Calreticulin (CALR) somatic mutations provide a diagnostic marker in JAK2/MPL wild type essential thrombocythemia (ET) and primary myelofibrosis (PMF) with a mutation frequency of 67% to 71% and 56% to 88%, respectively (Tefferi A and Pardanani A, Nat Rev Clin Oncol, 2014). In general, CALR mutations are not seen in Polycythemia Vera (PV), post-PV myelofibrosis or JAK2 V617F or MPL mutated ET or PMF. Studies showed that CALR mutations may also provide prognostic information and therefore is a promising molecular marker for diagnosis and prognosis for patients with myeloproliferative neoplasm (MPN). The exact mechanism by which CALR mutations produce the myeloproliferative disease phenotype is unknown, but multiple studies have shown that CALR mutations disrupt the C-terminal endoplasmic reticulum -retention sequence (KDEL), generate a novel C-terminus, and activate the STAT5 pathway. A 40-year-old female with persistent moderate thrombocytosis was referred for evaluation. Workup was negative for pseudo-thrombocytosis. She was noted to have mild iron deficiency. Reactive thrombocytosis and essential thrombocytosis were considered in the differential diagnosis. She was referred for clinical testing of CALR mutation analysis after she was found negative for JAK2. Mutation screening of CALR Exon 09 by PCR based Sanger sequencing revealed a novel mutation c.1191_1199del (p.E398_D400del) in this patient with African American ethnicity. Mutation status in CALR will aid the diagnosis of ET and PMF patients and risk stratification.

Survival and prognosis of patients with polycythemia vera: a study of 816 patients in a single Chinese center

To explore the survival and the risk factors of poor prognosis in Chinese patients with polycythemia vera (PV). A total of 816 patients with a definite diagnosis of PV were enrolled from August 1983 to June 2013 into this study. The standardized mortality ratio (SMR) was calculated by comparing the cumulative survival of 816 PV patients with age- and sex- and calendar year-matched healthy Chinese population from the national bureau of statistics of the People's Republic of China. The clinical features of diagnosis and prognosis of PV patients were analyzed by Cox regression to identify risk factors for the poor prognosis of PV and to develop a dynamic prognostic model in Chinese patients. The effects of different treatments on the development of acute myelocytic leukemia (AML) and post-PV myelofibrosis (post-PV MF) were determined by Kaplan-Meier analysis. JAK2 V617F allele burden (V617F%) was determined by quantitative real-time PCR in 104 patients. The median follow-up time was 6 (1-42) years. The 10-, 15- and 20-year overall survival (OS) was 89.50%, 76.70% and 64.70%, respectively. The SMR was 17.40 (95% CI: 13.71-21.78). Cox regression analysis revealed that white blood cell (WBC) count>10×10(9)/L (HR=3.10, 95% CI: 1.47-6.53, P=0.003), age>60 years (HR=2.89, 95% CI: 1.84-4.53, P<0.001) and prior thrombosis (HR=2.66, 95% CI: 1.65-4.29, P<0.001) were significant predictors for the poor prognosis of PV. Based on the hazard radio, 816 patents were allocated into 4 categories with significantly different survival: low (sum of points=0; median survival no reached), intermediate 1 (sum of points=1; median survival 33.10 (28.20-38.00) years), intermediate 2 (sum of points=2; median survival 23.00 (16.08-29.92) years), high (sum of points=3; median survival 13.00 (10.58-15.42) years). The mortality of high risk group was 5.37 fold higher than low risk patients. The 10- and 20-year survival of no post-PV MF were 89.50% and 79.60%, respectively, for interferon α (IFN-α); 73.80% and 43.50%, respectively, for hydroxyurea treatment; 82.20% and 71.40%, respectively, for alkylating agent treatment; and 80.00% and 38.20%, respectively, for no cytoreductive treatment. The treatment of exposure to IFN-α associated with a higher rate of no-post-PV MF survival (Log-rank=9.79, P=0.020). There were more post-PV MF patients with V617F%≥50% compared with those V617F%<50% (P<0.001). The mortality of PV patients is significantly higher than that of healthy Chinese population. The WBC count>10×10(9)/L, age>60 years, and prior thrombosis are identified as significant predictors for the prognosis of PV. The risk of post-PV MF transformation may be ameliorated by IFN-α via decreasing the burden of JAK2 V617F mutation.

A Phase 1/2, Open-Label, Dose-Escalation, Multi-Center Study to Assess the Safety, Tolerability, Pharmacokinetics, and Pharmacodynamics of Orally Administered NS-018 in Patients with Primary Myelofibrosis (PMF), Post-Polycythemia Vera Myelofibrosis (postPV MF), or Post-Essential Thrombocythemia Myelofibrosis (postET MF)

Background: NS-018 is an oral, selective, small molecule inhibitor of Janus kinase 2 (JAK2). Pre-clinically NS-018 inhibited JAK2 kinase with an IC50 value in the subnanomolar range and demonstrated splenomegaly reduction at low doses in a JAK2V617F-bearing mouse model (Blood Cancer J 2011; 1: e29.).Methods: This multicenter, Phase 1/2, 3+3 dose-escalation study of NS-018 enrolled patients with IPSS intermediate-1, intermediate-2, or high risk PMF, postPV MF, or postET MF. Patients were ≥ 18 years, had ECOG PS ≤ 2 and required therapy but were not required to have splenomegaly in Phase 1. NS-018 was dosed orally daily (QD) or twice daily (BID) in 28-day cycles. Responses were assessed according to IWG consensus criteria, changes in spleen size by manual palpation and quality of life with the Myelofibrosis Symptom Assessment Form (MF-SAF). The Phase 1 portion of the study completed enrollment and is presented here.Results:Patients: 42 patients were enrolled across 10 cohorts. Patient characteristics: 33 PMF, 5 postPV MF, 4 postET MF; median age (range) 69 yrs (43-83); M/F:28/14; 31 JAK2V617F+, and 17 previously treated with a different JAK inhibitor.Dosing and tolerability: Dose levels included 75, 125, 200, 300 and 400 mg QD and 100, 200, 250, 300 and 400 mg BID. Systemic exposures based on Cmax were approximately dose proportional across the tested range from 75 to 400 mg.The recommended Phase 2 dose (RP2D) was 300 mg BID, based on drug-related neurological adverse events (AEs) at 400 mg BID including dizziness (Grade 2 or 3), dysphagia (Grade 2) or hypoesthesia (Grade 1) in one patient each that led to dose reduction or drug discontinuation.Study drug-related serious AEs (SAEs) included non-cardiac chest pain (Grade 2, 200 and 300 mg BID), lower GI hemorrhage (Grade 3, 300mg BID), paresthesia (Grade 3, 300mg BID), increased lipase (Grade 2, 300mg BID), and dizziness (Grade 3, 400 mg BID) in one patient each.For the 300 mg BID cohort (n=11), the most frequent drug-related AEs across all grades were nausea (Grade 1, 18%), decreased platelet count (≤ Grade 2, 18%), and dizziness (≤ Grade 2, 27%); Grade 3 related AEs included anemia, lower GI bleed, leukopenia, neutropenia or paresthesia (1 patient each, 9%); and no Grade 4 AEs.Overall, 22 patients (52%) discontinued treatment due to AEs (n=7), progressive disease (PD) (n=7), or MD/patient decision (n=8). The AEs leading to discontinuation included thrombocytopenia (Grade 4), transient ischemic attack (Grade 2), muscle contraction involuntary (Grade 2), light headedness (Grade 1), insomnia (Grade 1), hemolytic anemia (Grade 3), dizziness (Grade 2), dysphagia (Grade 2), and hypoesthesia (Grade 1). Nine patients had a hemoglobin decrease ≥ 2 g/dL and 8 patients a platelet decrease ≥ 50%.Responses: Of 33 evaluable patients with baseline splenomegaly ≥ 5 cm and treatment for ≥ 1 cycle, 16 (48%) patients showed ≥ 50% reduction in spleen size (confirmed for ≥ 8 weeks in 11 patients). In addition, 11 patients showed splenic clinical improvement (CI, for ≥ 8 weeks), 3 patients hemoglobin CI, and 2 patients platelet CI. Median (range) time to splenic response and duration of response: 1.5 cycle (1-12) and 4.5 cycles (1-29). Splenic reductions ≥50% are shown in the Table for the specified patient groups. Changes in MF-SAF and PK and PD results will be presented.TableSplenic reduction(in evaluable patients)All doses16/33 (48%)300mg BID3/6 (50%)300mg QD4/7 (57%)Prior different JAK inhibitor treated8/16 (50%)Conclusions: The dose of NS-018 determined to be the RP2D in Phase 1 was 300 mg BID. This dose provided a durable dosing schedule with an acceptable safety profile, and was associated with splenic size reduction and clinical improvements. The Phase 2 portion of the study is ongoing and includes only patients previously treated with a different JAK inhibitor. DisclosuresVerstovsek:NS Pharma, Inc: Research Funding. Talpaz:Ariad, BMS, Sanofi, Pfizer, Incyte: Research Funding. Ritchie:Celgene, Incyte: Speakers Bureau. Odenike:Suneisis Pharmaceuticals, Incyte, Sanofi-Aventis, Algeta Pharmaceuticals, Spectrum Pharmaceuticals: Honoraria, Membership on an entity’s Board of Directors or advisory committees. Jamieson:Roche, Johnson&Johnson, CTI: Research Funding. Stein:Incyte Corporation: Honoraria, Speakers Bureau; Sanofi Oncology: Honoraria. Tomonori:NS Pharma, Inc.: Employment. Mesa:Incyte, CTI, NS Pharma, Inc., Gilead, Celgene: Research Funding.

Clinicopathologic Features and Outcome of Chinese Patients with Myelofibrosis

IntroductionMyelofibrosis (MF) is a myeloproliferative neoplasm (MPN) comprising primary myelofibrosis (PMF) and myelofibrosis developing from either polycythemia vera (post-PV MF) or essential thrombocythemia (post-ET MF).MethodsTwo hundred and sixty-seven consecutive patients with MF (PMF, N=206); post-PV MF, N=26; post-ET MF, N=35) diagnosed between January 1988 and December 2013 at seven regional hospitals in Hong Kong were prospectively followed up. Data on the clinicopathologic features and treatment outcome were collected.ResultsThe median duration of follow-up was 45 (1 – 247) months. The median overall survival (OS) was 65 months (95% confidence interval, CI: 56.3–73.7). The 5-year and 10-year OS were 52.2% and 26.7% respectively. On univariate analysis, factors associated with an inferior OS included age > 65 years (hazard ratio ,HR, =1.81; 95% CI:1.33–2.48; P<0.001), the presence of constitutional symptoms (HR=1.52; 95% CI:1.11–2.08; P=0.009), hemoglobin < 10 g/dL (HR=1.71; 95% CI:1.25–2.35; P=0.001), circulating blasts ≥ 1% (HR=1.55; 95% CI:1.13–2.16; P=0.007), platelet < 100 x 109/L (HR=2.51; 95% CI:1.79–3.53; P<0.001), high risk IPSS (HR=3.09; 95% CI: 1.78–5.37; P<0.001), intermediate-2 risk DIPSS (HR=2.37; 95% CI: 1.38–4.06; P=0.002), high risk DIPSS (HR=2.92; 95% CI:1.51–5.64; P=0.001), transfusion dependence within the first year of diagnosis (HR=2.61; 95% CI:1.92–3.55; P<0.001), transfusion dependence after the first year of diagnosis (HR=2.42; 95% CI:1.61–3.54; P<0.001), palpable hepatomegaly at diagnosis (HR=1.44; 95% CI:1.06–1.96; P=0.02) and secondary AML (HR=1.75; 95% CI:1.24–2.47; P=0.001). On multivariate analysis, post-PV MF (P=0.03), platelet < 100 × 109/L (P=0.001), high risk IPSS (P=0.009), transfusion dependence within the first year (P=0.001), transfusion dependence after the first year (P=0.02), and transformation to secondary acute myeloid leukemia (AML) (P=0.007) were independent risks associated with inferior OS.On univariate analysis, factors associated with increased risk of secondary AML include age ≤ 55 years (odds ratio [OR] = 2.61; 95% CI:1.33–5.12; P=0.005), circulating blasts ≥ 1% (OR=2.24; 95% CI:1.18–4.26; P=0.01), transfusion dependence within the first year (OR=5.57; 95%:2.16–14.88; P<0.001), transfusion dependence after the first year (OR=5.57; 95% CI:2.16–14.88; P<0.001), hepatomegaly (OR=4.05; 95% CI:2.03–8.10), splenomegaly (OR=3.71; 95% CI:1.09–9.26; P=0.04), abnormal karyotypes (OR=3.3; 95% CI:1.14–9.56; P=0.02), and the presence of unfavourable karyotypes (OR=4.9; 95% CI: 1.22–19.96). On multivariate analysis, transfusion dependence within the first year of diagnosis (P=0.04), transfusion dependence after the first year of diagnosis (P=0.003) and hepatomegaly (P=0.006) were independent risks associated with secondary AML.The 5-year and 10-year risks of leukemic transformation were 17.1% and 29.7 respectively. Factors associated with inferior leukemia-free survival (LFS) on univariate analysis included post-ET MF (HR=2.15; 95% CI: 1.03–4.50; P=0.04), presence of constitutional symptoms (HR=1.85; 95% CI:1.04–3.31; P=0.04), circulating blasts ≥ 1% (HR=2.89; 95% CI:1.62–5.16; P<0.001), platelet count < 100 x 109/L (HR=2.56; 95% CI: 1.35–4.84; P=0.004), transfusion dependence within the first year of diagnosis (HR=3.05; 95% CI: 1.70–5.50; P<0.001), transfusion dependence after the first year of diagnosis (HR=6.49; 95% CI: 2.33–18.10; P<0.001), hepatomegaly (HR=3.21; 95% CI:1.69–6.08; P<0.001) and unfavorable karyotype (HR=3.01; 95% CI:1.08–8.35; P=0.03). On multivariate analysis, male gender (P=0.05), presence of constitutional symptoms (P=0.04) and unfavorable karyotypes (P=0.01) were independent risks associated with inferior LFS.Eighteen patients underwent allogeneic haematopoietic stem cell transplantation (HSCT) (matched sibling, N=14; matched-unrelated, N=4), with 15 patients achieving complete remission. Seven patients relapsed with subsequent progression to secondary AML. Acute and chronic graft-versus-host disease occurred in seven (39.9%) and six (33.3%) patients respectively. Transplant-related mortality occurred in three patients. The 5-year and 10-year OS following HSCT was 51.5%.ConclusionFindings of this study complement current prognostic models in guiding treatment decisions at diagnosis and during the course of MF. DisclosuresNo relevant conflicts of interest to declare.

Phase 2 Trial of PRM-151, an Anti-Fibrotic Agent, in Patients with Myelofibrosis: Stage 1 Results

Phase 2 Trial of PRM-151, an Anti-Fibrotic Agent, in Patients with Myelofibrosis: Stage 1 Results

Favorable Results of Allo-HSCT from MRD in Patients with Myelofibrosis

Introduction: Myelofibrosis (MF), chronic myeloid malignancy associated with shortened survival, in majority of patients develops de novo as Primary MF, but also polycythemia vera (PV) or essential thrombocythemia (ET) may progress into post-PV or post-ET MF. Although management of MF includes several treatment options, the only potentially curative treatment approach in MF is allogeneic hematopoietic stem cell transplantation (allo-HSCT). Aim of this study was to evaluate the results of allo-HSCT in patients with MF treated in Katowice, Poland.Material and Methods: 27 pts (14 male and 13 female) with median age 51 years (range 21–63) were treated with allo-HCT due to PMF (20), post-PV (4) or post-ET (3) MF. 11,7,11,26 and 41% of pts had DIPSS 0,1,2,3 and 4, respectively. Median bone marrow cellularity was 70% (10-100%), fibrosis was collagen-type (14 pts including 2 with osteosclerosis), reticulin (10) or it was not specified (3). Splenomegaly was present in all pts: 13-20 cm (14 pts), > 20 cm (13 pts). JAK2V617F point mutation was present in 18 pts. Karyotype was available in 14 pts: in 9 normal, in 5 with variable abnormalities. Median time from diagnosis to allo-HCT was 1.5 (0.4–9.5) years. 16 pts (59.3%) received cells from HLA-matched related donor (MRD), 11 pts (40.7%) from unrelated donor: 10/10 (9) or 9/10 (2) HLA-A,B,C,DR,DQ alleles matched. Reduced intensity conditioning (RIC) was used in 26 pts, 1 patient received myeloablative conditioning (MC). Sources of stem cells were: peripheral blood (21), bone marrow (4) and both (2). All pts but one had chronic phase of MF at time of transplantation.Results: 14/27 (52%) pts are alive at median 3.4 (0.4-5.4) years after allo-HSCT: 11/16(69%) from MRD and 3/11(27%) from MUD, p=0.032. Graft failure, graft loss or PRCA were observed in 3, 5 and 1 pt, respectively. Absolute neutrophil count >0.5×109/L and platelet count >50×109/L were achieved at median 16 and 28 days, respectively. 12/27 (44%) pts reached complete blood count of Hb>10 g/dl, Plt>100 G/l and WBC>3.5 G/l; 11 of them (92%) are alive. 6/27 (22%) pts remained either RBC or PLT transfusions dependent post-transplant; 3 of them (50%) died. 9/27 (33%) pts remained both RBC and PLT transfusion dependent and all of them died. JAK2V617F mutation was completely eradicated in 11/16 evaluated previously positive patients (69%), decreased in 4 (25%) and stable in 1(6%) pt. Acute graft-versus-host disease (aGVHD) III-IV developed in 5/27 (19%) and extensive chronic GVHD in 5/19 (26%) pts. Relapse occurred in 4 pts and was treated with subsequent second transplant (in 1 pt thereafter by 3-rd allo-HSCT). Spleen length decreased at median by 5 (0.3-9.2) cm. Out of 7 pts with initial collagen fibrosis who were evaluated post-transplant, 1 had no fibrosis, 5 reticulin type and only in 1 pt collagen fibrosis was stable. Out of 3 pts with initial reticulin fibrosis it disappeared in 2 and progressed to collagen type in 1. Causes of death were GVHD (5 pts: 3 aGVHD, 2 cGVHD) and pancytopenia with either infection (7 pts) or CNS hemorrhage (1 pt).Conclusions: Allo-HSCT, the only curative treatment of myelofibrosis, provides chance of long survival, regression of the disease (lower stage of fibrosis, JAK2V617F eradication) and improved quality of life (transfusion independency, decreased splenomegaly). Transfusion independency may indicate good outcome. Favorable results are observed after allo-HSCT from MRD. DisclosuresNo relevant conflicts of interest to declare.

Nitric Oxide As a Mediator of Bone Marrow Fibrosis in Patients with Myelofibrosis

Bone marrow (BM) fibrosis is a key pathomorphologic feature of patients (pts) with primary myelofibrosis (PMF) and the fibrotic phases of essential thrombocythemia (post-ET MF) and polycythemia vera (post-PV MF). The degree of BM fibrosis appears to correlate with survival. Indeed worse survival has been associated with increased BM fibrosis. The BM stromal microenvironment is important in the pathogenesis of BM fibrosis. Cellular components (fibroblasts, macrophages, endothelial cells, adipocytes), structural fibrils (collagen, reticulin) and extracellular matrix components are all forming elements of the BM stroma. Increased stromal fibrosis has been linked to abnormalities in the number/ function of megakaryocytes and platelets in hematologic diseases. Several cytokines like Platelet Derived Growth Factor (PDGF) and Transforming Growth Factor-Beta (TGF-b) have been also linked to the pathophysiology of BM fibrosis. PDGF has been shown to increase fibroblast growth in megakaryocytes and platelets although increased PDGF did not correlate with increased production of either reticulin or collagenous fibrosis. Moreover, PMF pts have increased TGF-b levels in platelets, megakaryocytes, and monocytes. Nitric Oxide (NO) is a ubiquitous gas important in physiologic processes particularly vasodilatation. Dysregulation of NO levels has been implicated in pulmonary hypertension (PH), hemoglobinopathies, and cardiovascular diseases. In Peyronie’s disease, a localized fibrosis of the penile tunica albuginea, increased NO production by expression of iNOS decreases collagen deposition by neutralization of profibrotic reactive oxygen species and decreased myofibroblast formation. Aside from its role in maintaining normal vascular tone, NO also plays a role in fibroblast formation and collagen biosynthesis. We previously reported that ruxolitinib, a JAK1/2 inhibitor restores NO levels leading to improvement of PH in MF pts (Tabarroki et al., Leukemia 2014). We now hypothesize that plasma/serum NO level is a key regulator of BM fibrosis in MF and that ruxolitinib treatment (Tx) leads to improvement of BM fibrosis by NO modulation. Using a Sievers 280i NO analyzer we measured the plasma/serum NO level of a large cohort (n=75) of pts with myeloid and myeloproliferative neoplasms (MPN) [MDS, RARS/RCMD=8; MPN, ET=8, PV=8, MF=24, Mastocytosis=7; MDS/MPN, CMML=11, MDS/MPN-U, RARS-T=9]. Healthy subjects (n=10) were used as a control. MPN pts had low NO (nM) levels among the pts studied with the lowest level found in MF pts: MF=30.31±11.8, PV=39.0±16.1, ET=36±20.3, RARS=74.6±41.7 (P=.01), CMML=84.4±89.2 (P=.04), RCMD=163.4±103.8 (P<.001), RARS-T=131.1±99.8 (P<.001). In total, NO levels were lower in classic MPN (n=40, 35.3±16.6) compared to MDS (n=8, 119±62.8; P=.001) and MDS/MPN (n=20, 105±94.6; P=.008). When we looked at the correlation between NO levels and BM fibrosis grade we found that there is an inverse correlation between NO levels and worsening BM fibrosis grade from grade MF1 to MF3. NO levels in normal (n=10) vs MF1 (n=3) were 53.3 vs 39.1, P=.025; normal vs MF2 (n=7) were 53.3 vs 37, P=.021; normal vs MF3 (n=12) were 53.3 vs 34.4, P=.006. A total of 8 pts who were treated with ruxolitinib and had at least 1 pre and 1 post Tx (≥3 months from initiation of ruxolitinib) were tested for NO levels. Among the 8 pts, 4 pts who demonstrated improvement in BM scores had a trend towards improved NO levels after ruxolitinib Tx [NO pre vs post; pt #1: 6 vs 10.5; pt#2: 4.3 vs 6.4; pt#3 49.7 vs 52.1; pt#4 36 vs 41.3; P=.02] while 4 had worsening or had no change in BM fibrosis grade and had a minimal change or decline in the NO (pt#5: 18.4 vs 23, pt#6: 14.29 vs 12.1, pt#7: 32.7 vs 32.1, pt#8: 110.9 vs 40.4). One pt who had improvement in BM fibrosis grade after ruxolitinib Tx had increased iNOS expression by Western blotting (pt#1) while no iNOS expression (pt#5) was noted in the pt who did not have improvement in BM fibrosis. Of note, multi-analytic cytokines profile also showed an overall decrease in cytokines especially a 2.8 fold-decrease in IL8 levels post-Tx in the pt with improvement in BM fibrosis. In conclusion, NO is decreased in MPN particularly in MF and may be a key mediator of BM fibrosis in MF. Pharmacologic therapies such as JAK inhibitors may mediate improvement of BM fibrosis by modulation of NO levels in MF. DisclosuresTiu:Gilead: Membership on an entity’s Board of Directors or advisory committees; Novartis: Speakers Bureau; Incyte : Membership on an entity’s Board of Directors or advisory committees, Speakers Bureau.