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Simple Summary After the recent irruption of asciminib into the therapeutic arsenal for chronic myeloid leukemia, real-life data remain scarce to determine which patients may benefit most from this drug. Data on the efficacy of the drug in real-world setting have been reported, but a detailed analysis of the toxicity profile and the influence of prior intolerance to classical tyrosine kinase inhibitors (TKIs) has not been performed. The aim of the present analysis is to study in detail the toxicity profile of asciminib as well as to describe the risk of cross-toxicity with classical TKIs. These results may help to select the patient profile with the best chance of therapeutic success with asciminib monotherapy. (1) Background: Despite the prognostic improvements achieved with tyrosine kinase inhibitors (TKIs) in chronic myeloid leukemia (CML), a minority of patients still fail TKIs. The recent introduction of asciminib may be a promising option in intolerant patients, as it is a first-in-class inhibitor with a more selective mechanism of action different from the ATP-competitive inhibition that occurs with TKIs. Therefore, our goal was to analyze toxicities shown with asciminib as well as to study cross-toxicity with previous TKIs. (2) Methods: An observational, multicenter, retrospective study was performed with data from 77 patients with CML with therapeutic failure to second-generation TKIs who received asciminib through a managed-access program (MAP) (3) Results: With a median follow-up of 13.7 months, 22 patients (28.5%) discontinued treatment: 32% (7/22) due to intolerance and 45% (10/22) due to resistance. Fifty-five percent of the patients reported adverse effects (AEs) with asciminib and eighteen percent grade 3-4. Most frequent AEs were: fatigue (18%), thrombocytopenia (17%), anemia (12%), and arthralgias (12%). None of the patients experienced cardiovascular events or occlusive arterial disease. Further, 26%, 25%, and 9% of patients required dose adjustment, temporary suspension, or definitive discontinuation of treatment, respectively. Toxicities under asciminib seemed lower than with prior TKIs for anemia, cardiovascular events, pleural/pericardial effusion, diarrhea, and edema. Cross-toxicity risk was statistically significant for thrombocytopenia, anemia, neutropenia, fatigue, vomiting, and pancreatitis. (4) Conclusion: Asciminib is a molecule with a good safety profile and with a low rate of AEs. However, despite its new mechanism of action, asciminib presents a risk of cross-toxicity with classical TKIs for some AEs.

BACKGROUND AND AIMS Porto-sinusoidal vascular disease (PSVD) is a rare disease that requires excluding cirrhosis and other causes of portal hypertension for its diagnosis because it lacks a specific diagnostical test. Although it has been occasionally associated with autoimmune diseases, the pathophysiology of PSVD remains unknown. The aim of this study was to evaluate the potential role of autoimmunity in the pathophysiology and diagnosis of PSVD. METHODS Thirty-seven consecutive patients with PSVD and 39 with cirrhosis matched by gender, signs of portal hypertension and liver function were included (training set). By using Indirect Immunofluorescence, ELISA and slot-blot methods data 22 autoantibodies were identified in patients with PSVD and cirrhosis. Presence of anti-endothelial cells antibodies (AECA) was assayed by a cell-based ELISA. Thirty-one PSVD, 40 cirrhosis patients, 15 patients with splenomegaly associated with haematological disease and 14 healthy donors were included in a validation set. FINDINGS The proportion of patients with at least one positive antibody was statistically significantly higher in patients with PSVD compared with cirrhosis (92% vs 56%; P

We report the clinical presentation and risk factors for survival in 175 patients with myeloproliferative neoplasms (MPN) and COVID-19, diagnosed between February and June 2020. After a median follow-up of 50 days, mortality was higher than in the general population and reached 48% in myelofibrosis (MF). Univariate analysis, showed a significant relationship between death and age, male gender, decreased lymphocyte counts, need for respiratory support, comorbidities and diagnosis of MF, while no association with essential thrombocythemia (ET), polycythemia vera (PV), and prefibrotic-PMF (pre-PMF) was found. Regarding MPN-directed therapy ongoing at the time of COVID-19 diagnosis, Ruxolitinib (Ruxo) was significantly more frequent in patients who died in comparison with survivors (p=0.006). Conversely, multivariable analysis found no effect of Ruxo alone on mortality, but highlighted an increased risk of death in the 11 out of 45 patients who discontinued treatment. These findings were also confirmed in a propensity score matching analysis. In conclusion, we found a high risk of mortality during COVID-19 infection among MPN patients, especially in MF patients and/or discontinuing Ruxo at COVID-19 diagnosis. These findings call for deeper investigation on the role of Ruxo treatment and its interruption, in affecting mortality in MPN patients with COVID-19.

Background & Aims Myeloproliferative neoplasms (MPNs) are the most frequent cause of non-tumoural non-cirrhotic splanchnic vein thrombosis (NC-SVT). Diagnosis of MPN is based on blood cell count alterations, bone marrow histology, and detection of specific gene mutations. Next-generation sequencing (NGS) allows the simultaneous evaluation of multiple genes implicated in myeloid clonal pathology. The aim of this study was to evaluate the potential role of NGS in elucidating the aetiology of NC-SVT. Methods DNA samples from 80 patients (75 with idiopathic or exclusively local factor [Idiop/loc-NC-SVT] and 5 with MPN and NC-SVT [SVT-MPN] negative for Janus kinase 2 gene [JAK2] [V617F and exon 12], calreticulin gene [CALR], and thrombopoietin gene [MPL] mutations by classic techniques) were analysed by NGS. Mutations involved in myeloid disorders different from JAK2, CALR, and MPL genes were categorised as high-molecular-risk (HMR) variants or variants of unknown significance. Results In 2/5 triple-negative SVT-MPN cases (40%), a mutation in exon 12 of JAK2 was identified. JAK2-exon 12 mutation was also identified in 1/75 patients with Idiop/loc-NC-SVT. Moreover, 28/74 (37.8%) of the remaining Idiop/loc-NC-SVT had at least 1 HMR variant. Sixty-two patients with Idiop/loc-NC-SVT were not receiving long-term anticoagulation and 5 of them (8.1%) had recurrent NC-SVT. This cumulative incidence was significantly higher in patients with HMR variants than in those without. Conclusions NGS identified JAK2-exon12 mutations not previously detected by conventional techniques. In addition, NGS detected HMR variants in approximately one-third of patients with Idiop/loc-NC-SVT. These patients seem to have a higher risk of splanchnic rethrombosis. NGS might be a useful diagnostic tool in NC-SVT. Lay summary Next-generation sequencing (NGS) performs massive sequencing of DNA allowing the simultaneous evaluation of multiple genes even at very low mutational levels. Application of this technique in a cohort of patients with non-cirrhotic non-tumoral portal vein thrombosis (NC-SVT) and a negative study for thrombophilic disorders was able to identify patients with a mutation in exon 12 not previously detected by conventional techniques. Moreover, NGS detected High Molecular Risk (HMR)-variants (Mutations involved in myeloid disorders different from JAK2, CALR and MPL genes) in approximately one third of patients. These patients appear to be at increased risk of rethrombosis. All these findings supports NGS as a potential useful tool in the management of NC-SVT.

Background Warm autoimmune hemolytic anemia (WAIHA) is a disorder with a usually good response to corticosteroid treatment, whereas in some cases first-line treatment's response is poor and other therapies such as intravenous immunoglobulins (IVIGs), rituximab, or splenectomy must be applied. Study design and methods Herein, we describe two patients with severe WAIHA treated at our center, who obtained a response after therapeutic plasma exchanges (TPEs) combined with low doses of IVIG. Results The first patient was an 18-year-old man with no relevant past medical history who was diagnosed with WAIHA. The patient presented a progressive clinical worsening despite treatment with prednisone, IVIG, and rituximab. After starting TPEs, signs of hemolysis rapidly improved and hemoglobin started to recover. The second patient was a 38-year-old man with a past history of immune thrombocytopenia and WAIHA. The patient presented a new flare of WAIHA, with no response after 2 weeks of treatment with corticosteroids, IVIG, and rituximab. After initiation of TPEs, the patient had an improvement in hemolysis biomarkers and recovery of hemoglobin concentration. Conclusion Combination of TPEs with rituximab and IVIG might be considered as a therapeutic option in patients with severe WAIHA without response to corticosteroid and IVIG treatment.

Resumen Antecedentes y objetivo La mielofibrosis es una neoplasia mieloproliferativa cronica infrecuente. Nuestro objetivo fue describir las caracteristicas clinico-biologicas, el tratamiento y el curso evolutivo de los pacientes con mielofibrosis en Espana. Material y metodos Se analizaron 1.000 pacientes del Registro Espanol de Mielofibrosis diagnosticados de mielofibrosis primaria (n = 641) o secundaria (n = 359). Resultados La mediana de edad era de 68 anos. La frecuencia de sintomatologia constitucional, anemia moderada o severa (Hb Conclusiones la mielofibrosis es una enfermedad invalidante que afecta sobre todo a personas de edad avanzada y cuyo tratamiento es fundamentalmente sintomatico. A pesar de su heterogeneidad clinica se dispone de modelos pronosticos utiles para la seleccion de candidatos a trasplante.

BACKGROUND AND OBJECTIVE MYELOFIBROSIS: is an infrequent chronic myeloproliferative neoplasm. We aimed to describe the clinico-biological characteristics, treatment, and evolutive course of myelofibrosis patients in Spain.; MATERIAL AND METHODS: A total of 1,000 patients from the Spanish Registry of Myelofibrosis diagnosed with primary (n=641) or secondary (n=359) myelofibrosis were analysed.; RESULTS: Median age was 68 years. The frequency of constitutional symptoms, moderate to severe anaemia (Hb

Chronic myeloid leukemia (CML) is a myeloproliferative neoplasm treated with tyrosine kinase inhibitors (TKIs). Although survival rates have improved, response to these treatments is highly heterogeneous. Variations in response rates may be due to different causes such as, treatment adherence, mutations in the BCR-ABL1 gene, clonal evolution and amplification of the BCR-ABL1 gene, but innate immune response is also considered to play a very important role and, specifically, NK cell activity through their receptors and ligands, could be determinant. The aim of this retrospective study was to explore the role of different activating and inhibiting KIR genes as well as the activating NKG2D receptor, present in NK cells, and also their respective ligands, HLA-A, -B, -C, -G, -F, MICA and MICB, in the progression of 190 patients with CML and treated at two hospitals from Barcelona between 2000 and 2019. Early molecular response (EMR), major molecular response (MMR) or MR3.0 and deep molecular response (DMR) or MR4.0 were correlated. As control samples, healthy donors from the Barcelona Blood Bank were analyzed. The presence of KIR2DL2/KIR2DS2 was associated with the achievement of EMR, MR3.0, and MR4.0. Carriers of the higher expression NKG2D variant and MICA*009:01 were also likely to achieve molecular response (MR). The most remarkable difference between CML patients and controls was a higher frequency of the lower expression NKG2D variant in CML patients. In summary, our results showed that activating NK receptor phenotypes might help to achieve MR and DMR in CML patients treated with TKIs although confirmatory studies are necessary.

Allogeneic hematopoietic cell transplantation (allo-HCT) is increasingly used in older myelofibrosis (MF) patients, but its risk/benefit ratio compared to non-transplant approaches has not been evaluated in this population. We analyzed the outcomes of allo-HCT in 556 MF patients aged > 65years from the EBMT registry, and determined the excess mortality over the matched general population of MF patients > 65years managed with allo-HCT (n=556) or conventional drug treatment (n=176). The non-transplant cohort included patients with intermediate-2 or high risk DIPSS from the Spanish Myelofibrosis Registry. After a median follow-up of 3.4years, the estimated 5-year survival rate, non-relapse mortality (NRM), and relapse incidence after transplantation was 40%, 37%, and 25%, respectively. Busulfan-based conditioning was associated with decreased mortality (HR: 0.7, 95% CI: 0.5-0.9) whereas the recipient CMV+/donor CMV- combination (HR: 1.7, 95% CI: 1.2-2.4) and the JAK2 mutated genotype (HR: 1.9, 95% CI: 1.1-3.5) predicted higher mortality. Busulfan-based conditioning correlated with improved survival due to less NRM, despite its higher relapse rate when compared with melphalan-based regimens. Excess mortality was higher in transplanted patients than in the non-HCT cohort in the first year of follow-up (ratio: 1.93, 95% CI: 1.13-2.80), whereas the opposite occurred between the 4th and 8th follow-up years (ratio: 0.31, 95% CI: 0.18-0.53). Comparing the excess mortality of the two treatments, male patients seemed to benefit more than females from allo-HCT, mainly due to their worse prognosis with non-transplant approaches. These findings could potentially enhance counseling and treatment decision-making in elderly transplant-eligible MF patients. This article is protected by copyright. All rights reserved.

Triple-negative primary myelofibrosis (TN-PMF) and other myeloid neoplasms with associated bone marrow fibrosis such as the myelodysplastic syndromes (MDS-F) or the myelodysplastic/myeloproliferative neoplasms (MDS/MPN-F) are rare entities, often difficult to distinguish from each other. Thirty-four patients previously diagnosed with TN-PMF (n = 14), MDS-F (n = 18), or MDS/MPN-F (n = 2) were included in the present study. After central revision of the bone marrow histology, diagnoses according to the 2016-WHO classification were TN-PMF (n = 6), MDS-F (n = 19), and MDS/MPN-F (n = 9), with TN-PMF genotype representing only 4% of a cohort of 141 molecularly annotated PMF. Genomic classification according to next-generation sequencing and cytogenetic study was performed in 28 cases. Median number of mutations was 4 (range 1–7) in cases with TP53 disruption/aneuploidy or with chromatin-spliceosome mutations versus 1 mutation (range 0–2) in other molecular subgroups (p

Recommendations regarding management of essential thrombocythaemia rely on studies done before the discovery of the CALR mutation. On May 20, 2020, the European LeukemiaNet annual meeting was held with the goal to identify unmet clinical needs in myeloproliferative neoplasms. Because patients with a CALR mutation have specific clinical characteristics, treatment of CALR-mutated essential thrombocythaemia was considered an unmet clinical need by the European LeukemiaNet. The elaboration of a consensus document with recommendations according to current evidence was proposed as a solution for resolving uncertainties in the treatment of CALR-mutated essential thrombocythaemia. A steering committee comprising four European LeukemiaNet members was then formed and a panel of ten experts in the field was recruited. The experts proposed 51 potential unmet clinical needs in the management of CALR-mutated essential thrombocythaemia and were asked to score the relevance of each topic. Those topics that obtained the highest scores as relevant unmet clinical needs were identified, including antiplatelet therapy in patients at low risk, definition of extreme thrombocytosis and its management in patients at low risk, indications of cytoreduction and targets of therapy, first-line treatment of choice in young patients (60 years), and management of pregnancy. After the steering committee revised the available evidence for each topic, a consensus on management and proposal for improving knowledge was achieved by use of an email-based, two round, Delphi approach. Consensus was achieved when 90% of the panellists agreed with a statement and included 14 recommendations and six solution proposals. Key recommendations included careful observation for asymptomatic patients with classical, low-risk, CALR-mutated essential thrombocythaemia without cardiovascular risk factors; caution in the use of antiplatelet therapy for symptomatic patients at low risk with platelet counts of 1000-1500 × 10

In 2016, the WHO included haemoglobin values within normal ranges as a diagnostic criterion for Polycythaemia Vera (PV). Since then, concerns have arisen that a large number of patients are undergoing unnecessary screening for PV. To address this issue, we estimated the prevalence of JAK2 p.V617F in individuals with elevated haemoglobin or haematocrit and developed and validated a screening algorithm for PV. A total of 15,366 blood counts performed in seven non-consecutive days were reviewed, of which 1001 were selected for subsequent JAK2 p.V617F mutation screening. Eight (0.8%) new JAK2 p.V617F-mutated cases were detected. From ROC curves, a two-step algorithm was developed based on the optimal cut-off for the detection of the JAK2 p.V617F mutation. The algorithm was prospectively validated in an independent cohort of 15,298 blood counts. A total of 1595 (10.4%) cases met the criterion for haemoglobin or haematocrit, of whom 581 passed to step 2 (3.8% of the total). The JAK2 p.V617F mutation was detected in 7 of the 501 patients tested, which accounts for 0.04% of the total cohort and 0.4% of patients with erythrocytosis. In conclusion, this data show that our two-step algorithm improves the selection of candidates for JAK2 p.V617F testing.

In the midst of the COVID-19 pandemic, different vaccines in front of SARS-CoV-2 have been approved and administered in different vulnerable populations. As patients with cancer were excluded from pivotal trials of vaccination, little is known on their immunogenic response to these vaccines, particularly in patients with severely impaired immune system. In response to that uncertainty, the Spanish Society of Hematology and Hemotherapy launched an initiative aimed to provide recommendations for vaccination of the main hematological conditions. This document is based on the available information on COVID-19 outcomes, prior knowledge on vaccination in hematological patients, recent published data on serological response in oncohematological patients and expert opinions. New information about SARS-CoV-2 vaccination will be gathered in the near future, providing new scientific grounds to delineate the most adequate management of vaccination in patients with hematological diseases. The current limited data on SARS-CoV-2 vaccines in hematological patients represents a major limitation of this expert consensus opinion. In fact, the speed in which this field evolves may reduce their validity in the near future.

Essential thrombocythaemia is a classic myeloproliferative neoplasm characterized by thrombocytosis, increased risk of thrombotic and/or haemorrhagic complications, and a trend to transformation to myelofibrosis and acute leukaemia. Mutations in JAK2, CALR, and MPL genes besides bone marrow histology are crucial elements of diagnosis. Treatment is aimed to prevent the appearance of thrombotic complications that are the main cause of morbidity and mortality. Accordingly, thrombosis risk stratification is of the utmost importance to select the appropriate treatment. Antiplatelet therapy as primary antithrombotic prophylaxis in low-risk patients should be tailored according to the existence of extreme thrombocytosis and presence of JAK2V617F mutation and/or cardiovascular risk factors. Cytoreductive treatment options are discussed with reference to results of randomized clinical trials. Practical approach to unusual and risk situations as surgery, pregnancy, and paediatric essential thrombocythaemia are also reviewed.

Patients with polycythemia vera (PV) or essential thrombocythemia (ET) presenting with splanchnic vein thrombosis (SVT) might have a specific clinico-biological profile. To investigate this hypothesis, 3705 PV/ET patients from three national registers, 118 of them presenting with SVT, were reviewed. After correction for age and sex, PV/ET patients with SVT showed an increased risk of death (HR 2.47, 95% CI 1.5–4.01, p

Myelofibrosis (MF) occurs as part of the natural history of polycythemia vera (PV) and essential thrombocythemia (ET), and remarkably shortens survival. Although JAK2V617F and CALR allele burden are the main transformation risk factors, inflammation plays a critical role by driving clonal expansion toward end-stage disease. NF-kappa B is a key mediator of inflammation-induced carcinogenesis. Here, we explored the involvement of miR-146a, a brake in NF-kappa B signaling, in MPN susceptibility and progression. rs2910164 and rs2431697, that affect miR-146a expression, were analyzed in 967 MPN (320 PV/333 ET/314 MF) patients and 600 controls. We found that rs2431697 TT genotype was associated with MF, particularly with post-PV/ET MF (HR = 1.5; p < 0.05). Among 232 PV/ET patients (follow-up time=8.5 years), 18 (7.8%) progressed to MF, being MF-free-survival shorter for rs2431697 TT than CC + CT patients (p = 0.01). Multivariate analysis identified TT genotype as independent predictor of MF progression. In addition, TT (vs. CC + CT) patients showed increased plasma inflammatory cytokines. Finally, miR-146a(-/-) mice showed significantly higher Stat3 activity with aging, parallel to the development of the MF-like phenotype. In conclusion, we demonstrated that rs2431697 TT genotype is an early predictor of MF progression independent of the JAK2V617F allele burden. Low levels of miR-146a contribute to the MF phenotype by increasing Stat3 signaling.

Accurate prognostic tools are crucial to assess the risk/benefit ratio of allogeneic hematopoietic cell transplantation (allo-HCT) in patients with myelofibrosis (MF). We aimed to evaluate the performance of the Myelofibrosis Transplant Scoring System (MTSS) and identify risk factors for survival in a multicenter series of 197 patients with MF undergoing allo-HCT. After a median follow-up of 3.1 years, 47% of patients had died, and the estimated 5 year survival rate was 51%. Projected 5-year risk of nonrelapse mortality and relapse incidence was 30% and 20%, respectively. Factors independently associated with increased mortality were a hematopoietic cell transplantation-specific comorbidity index (HCT-CI) 3 and receiving a graft from an HLA-mismatched unrelated donor or cord blood, whereas post-transplant cyclophosphamide (PT-Cy) was associated with improved survival. Donor type was the only parameter included in the MTSS model with independent prognostic value for survival. According to the MTSS, 3-year survival was 62%, 66%, 37%, and 17% for low-, intermediate-, high-, and very high-risk groups, respectively. By pooling together the lowand intermediate-risk groups, as well as the highand very high-risk groups, we pinpointed 2 categories: standard risk and high risk (25% of the series). Three-year survival was 62% in standard-risk and 25% in high-risk categories (P < .001). We derived a risk score based on the 3 independent risk factors for survival in our series (donor type, HCT-CI, and PT-Cy). The corresponding 5-year survival for the low-, intermediate-, and high-risk categories was 79%, 55%, and 32%, respectively (P < .001). In conclusion, the MTSS model failed to clearly delineate 4 prognostic groups in our series but may still be useful to identify a subset of patients with poor outcome. We provide a simple prognostic scoring system for risk/benefit considerations before transplantation in patients with MF. (C) 2020 American Society for Transplantation and Cellular Therapy. Published by Elsevier Inc.

BACKGROUND AND OBJECTIVE MYELOFIBROSIS: is an infrequent chronic myeloproliferative neoplasm. We aimed to describe the clinico-biological characteristics, treatment, and evolutive course of myelofibrosis patients in Spain.A total of 1,000 patients from the Spanish Registry of Myelofibrosis diagnosed with primary (n=641) or secondary (n=359) myelofibrosis were analysed.Median age was 68 years. The frequency of constitutional symptoms, moderate to severe anaemia (Hb10g/dL), and symptomatic splenomegaly was 35%, 36%, and 17%, respectively. The rate of thrombosis and haemorrhage was 1.96 and 1.6 events per 100 patient-years, respectively. The cumulative incidence of leukaemia at 10 years was 15%. The most frequent therapies for the anaemia were the erythropoiesis stimulating agents and danazol. From 2010, a progressive increase in the use of ruxolitinib was noticed. A total of 7.5% of patients were transplanted. During the observation period, 42% of patients died mainly due to the clinical deterioration caused by myelofibrosis or leukaemic transformation. The median survival of the series was 5.7 years. Four different risk categories were identified by the IPSS: median survival was not reached in the low risk group and was 8.8 years, 5.3 years, and 2.8 years in the intermediate-1, intermediate-2, and high-risk groups, respectively.Myelofibrosis is a disabling condition mainly affecting elderly people. Its treatment is mostly driven by symptom control. Despite its clinical heterogeneity, several prognostic models are useful to select candidates for transplantation.

AimTo characterise the clinical and histological features of MPL-mutated essential thrombocythaemia (ET).Patients and methodsBone marrow biopsies of 175 patients with ET were centrally reviewed according to the 2016 WHO classification, including 42 cases with MPL mutation, 98 JAK2V617F-mutated and 35 CALR-mutated. Clinical and histological features were compared among the three genotypes included in the current 2016 WHO classification and among the different types of MPL mutations.ResultsPatients with MPL-mutated ET were significantly older than those with the other genotypes. Haematological values at diagnosis were similar among MPL-mutated and CALR-mutated ET, with both genotypes showing higher platelet counts and lower haemoglobin values than ET with JAK2V617F genotype. In the bone marrow, the median number of megakaryocytes was higher in MPL and CALR than in JAK2V617F genotype (16, 19 and 14 megakaryocytes per ×20 power field, respectively, p=0.004). Histological features of prefibrotic myelofibrosis were rarely observed in MPL genotype, whereas sinusoidal hyperplasia, dense clusters of megakaryocytes and reticulin fibrosis were more frequent in CALR-mutated ET, with 11% of such cases fulfilling WHO 2016 histological criteria of prefibrotic myelofibrosis. With a median follow-up of 3.5 years, no significant differences were seen among genotypes regarding survival, vascular complications or myelofibrotic transformation. There were no significant differences in the clinical data or in the histological characteristics depending on the type of MPL mutation.ConclusionMPL and CALR ET genotypes share clinical and histological characteristics. In contrast to CALR genotype, features of prefibrotic myelofibrosis are uncommon in MPL-mutated ET.

Introduction. MPN-COVID is a European LeukemiaNet cohort study, launched in March 2020 in patients with myeloproliferative neoplasms (MPN) with COVID-19. The first cohort of 175 cases was analyzed at the end of first wave (July 2020) and results provided estimates and risk factors of overall mortality (Barbui T. Leukemia, 2021), thrombosis incidence (Barbui T. Blood Cancer J, 2021), and post-COVID outcomes (Barbui T. Blood Cancer J, 2021). In the second wave of pandemic (June 2020 to June 2021), case-fatality risk in the general population has been found variable across different countries, and no information is available in MPN patients with COVID-19 diagnosed during the second wave in comparison with those of the first wave. Methods. In an electronic case report form, we registered a total of 479 cases of ET (n=161, 34%), PV (n=135, 28%), pre-PMF (n=49, 10%) and overt MF (n=134, 28%), from 39 European hematology units (Italy, Spain, Germany, France, UK, Poland, Croatia). Of these, 304 were diagnosed COVID-19 during the second wave. Results. Patients in the second wave were significantly different from those in the first wave, including parameters such as age (median: 63 vs. 71 years, p Conclusions. This is the largest series of MPN patients who incurred COVID-19 from June 2020 onward, namely during the "second COVID-19 wave". Compared to the first wave, the second one recorded a lower overall COVID-19 severity, but Ruxolitinib discontinuation still remained a risk factor for a dismal outcome. Greater vulnerability of ET than PV in developing venous thrombosis was confirmed also during the second wave. This finding suggests that ET warrants a specific antithrombotic prophylaxis in addition to heparin. Figure 1 Figure 1. Disclosures Barbui: AOP Orphan: Membership on an entity's Board of Directors or advisory committees, Research Funding; Novartis: Membership on an entity's Board of Directors or advisory committees, Research Funding. Iurlo: Novartis: Speakers Bureau; Incyte: Speakers Bureau; Pfizer: Speakers Bureau; Bristol Myers Squibb: Speakers Bureau. Sobas: Celgene: Consultancy, Honoraria; Novartis: Consultancy, Honoraria. Fox: Novartis: Honoraria; Sierra: Honoraria. Palandri: AOP: Membership on an entity's Board of Directors or advisory committees; CTI: Consultancy; Sierra Oncology: Membership on an entity's Board of Directors or advisory committees; Celgene: Membership on an entity's Board of Directors or advisory committees; Novartis: Membership on an entity's Board of Directors or advisory committees. Benevolo: Novartis: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Janssen: Membership on an entity's Board of Directors or advisory committees; Takeda: Membership on an entity's Board of Directors or advisory committees; BMS: Membership on an entity's Board of Directors or advisory committees; Amgen: Speakers Bureau. Harrison: Gilead Sciences: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Roche: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Sierra Oncology: Honoraria; Galacteo: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Promedior: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; CTI BioPharma: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Celgene: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau; Shire: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Incyte Corporation: Speakers Bureau; BMS: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Keros: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Janssen: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Novartis: Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau; Geron: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; AOP Orphan Pharmaceuticals: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Constellation Pharmaceuticals: Research Funding; Abbvie: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau. Bonifacio: Pfizer: Membership on an entity's Board of Directors or advisory committees; Novartis: Membership on an entity's Board of Directors or advisory committees; Bristol Myers Squibb: Membership on an entity's Board of Directors or advisory committees; Amgen: Membership on an entity's Board of Directors or advisory committees. Kiladjian: Taiho Oncology, Inc.: Research Funding; Bristol Myers Squibb: Membership on an entity's Board of Directors or advisory committees; Incyte Corporation: Membership on an entity's Board of Directors or advisory committees; Novartis: Membership on an entity's Board of Directors or advisory committees; PharmaEssentia: Other: Personal fees; AOP Orphan: Membership on an entity's Board of Directors or advisory committees; AbbVie: Membership on an entity's Board of Directors or advisory committees. Patriarca: Incyte: Honoraria; Takeda: Honoraria; Argenix: Honoraria; Novartis: Honoraria; Amgen: Honoraria; Pfizer: Honoraria. Griesshammer: Janssen: Consultancy, Honoraria; Roche: Consultancy, Honoraria; Shire: Consultancy, Honoraria; Pfizer: Consultancy, Honoraria; Celgene: Consultancy, Honoraria; Novartis: Consultancy, Honoraria; Amgen: Consultancy, Honoraria; AOP Orphan: Consultancy, Honoraria; CTI: Consultancy, Honoraria; Gilead: Consultancy, Honoraria; Astra Zeneca: Consultancy, Honoraria. Garcia Gutierrez: Pfizer: Consultancy, Honoraria, Research Funding; Incyte: Consultancy, Honoraria, Research Funding; BMS: Consultancy, Honoraria, Research Funding; Novartis: Consultancy, Honoraria, Research Funding. Osorio: Janssen, Abbvie, Roche: Consultancy. Koschmieder: CTI: Membership on an entity's Board of Directors or advisory committees, Other; BMS: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Other: (e.g. travel support); Bristol-Myers Squibb: Honoraria, Membership on an entity's Board of Directors or advisory committees, Other: Travel support, Research Funding; Baxalta: Membership on an entity's Board of Directors or advisory committees, Other; Abbvie: Other: Travel support; Alexion: Other: Travel support; Karthos: Other: Travel support; Sanofi: Membership on an entity's Board of Directors or advisory committees, Other: Travel support; Image Biosciences: Other: Travel support; AOP Pharma: Honoraria, Membership on an entity's Board of Directors or advisory committees, Other: (e.g. travel support), Research Funding; Celgene: Honoraria, Membership on an entity's Board of Directors or advisory committees, Other: (e.g. travel support); Incyte: Honoraria, Membership on an entity's Board of Directors or advisory committees, Other: (e.g. travel support); Janssen: Honoraria, Membership on an entity's Board of Directors or advisory committees, Other: (e.g. travel support), Research Funding; Geron: Honoraria, Membership on an entity's Board of Directors or advisory committees, Other: (e.g. travel support), Research Funding; Roche: Honoraria, Membership on an entity's Board of Directors or advisory committees; Novartis: Honoraria, Membership on an entity's Board of Directors or advisory committees, Other: Travel support, Research Funding; Ariad: Honoraria, Membership on an entity's Board of Directors or advisory committees, Other: (e.g. travel support); Pfizer: Honoraria, Membership on an entity's Board of Directors or advisory committees, Other: (e.g. travel support); Shire: Honoraria, Other. Vannucchi: Incyte: Honoraria, Membership on an entity's Board of Directors or advisory committees; Novartis: Honoraria, Membership on an entity's Board of Directors or advisory committees; BMS: Honoraria, Membership on an entity's Board of Directors or advisory committees; AbbVie: Membership on an entity's Board of Directors or advisory committees.

Background: Ruxolitinib is the standard of care for myelofibrosis (MF). However not all patients respond to ruxolitinib and other lose response while on treatment or require discontinuation due to adverse events. Therefore, several clinical trials with ruxolitinib in combination with other drugs are being conducted. We previously showed the synergistic effect of the combination ruxolitinib/nilotinib/prednisone in ex vivo models of peripheral blood mononuclear cells from MF patients and cell lines. Aims: This phase Ib/II study, non-randomized, open-label, evaluates safety and tolerability of ruxolitinib in combination with nilotinib and prednisone in patients with naïve or ruxolitinib-resistant MF. Methods:Between November 2017 and June 2020, 21 patients were included in RUNIC (EudraCT Number:2016-005214-21) at 6 Spanish sites. Six patients were considered screening failures. A total of 15 patients received at least one dose of ruxolitinib and were included in the intention-to-treat (ITT) or the per-protocol (PP) populations. The study design is summarized in figure 1. Out of 15 evaluable patients whose median age was 66.5 years (53.4-70.8). Six patients (40%) had a diagnosis of primary MF, 4 patients (26.7%) post-polycythemia vera MF, and 4 patients (26.7%) post-essential thrombocythemia MF. Most patients had International Prognostic Scoring System (IPSS) intermediate-1 or -2 disease (5 [33.3%] and 4 [26.7%], respectively), and 9 patients (60%) had JAK2 V617F mutation. Most of the patients (n=13; 86.7%) had received ruxolitinib as previous anti-neoplastic therapy for MF. Results:Eight patients completed 7 cycles (53.3%), and six patients 12 cycles (40%) and nine patients withdrawn because of disease progression, lack of efficacy, or no clinical benefit (n=5), withdrawal of consent (n=2), adverse event (AE) (pulmonary thromboembolism, n=1), and investigator's medical judgment (n=1). All patients experienced at least one AE during the study (the most common were hyperglycemia, asthenia and thrombocytopenia, and 14 patients registered at least one treatment-related AE (the most common were hyperglycemia (22.2%), thrombocytopenia (13.3%), and anemia (8.9%)). Five treatment-related serious adverse events (SAEs) were reported in 2 patients (13.3%), all of them related to nilotinib: one patient had pericardial effusion and bilateral pleural effusion, the other had congestive heart failure, pleural effusion, and pulmonary hypertension. No deaths were registered throughout the study.There were 2 patients with at least one adverse event meeting criteria for dose-limiting toxicity: grade 4 anemia and lumbar pain. Only eight patients were evaluated for spleen lengths at screening and cycle 7 (Figure 2B). Of these, 6 experienced a palpable spleen reduction, 4 of them with a 100% reduction. In contrast, one patient remained with the same spleen length, and one patient experienced a 25% increase.Six patients had both symptom evaluation at screening and cycle 7 (Figure 2D). Four experienced a total symptom score reduction, one patient remained with the same total symptom score, and two patients reported an increase.Six patients had spleen length measures recorded both at screening and at cycle 12. From those, 4 showed a spleen length reduction, 3 of them with a 100% reduction. Conclusions: Ruxolitinib in combination with nilotinib and prednisone showed relevant clinical activity in patients with naïve or ruxolitinib-resistant MF. The tolerability of this combination was acceptable, and the hyperglycemia was the treatment-related AE most frequent. The main cause of trial withdrawn was disease progression, lack of efficacy, or no clinical benefit. Based on these results, this triple combination should be explored in phase II/III clinical trials. Figure 1 Figure 1. Disclosures Ayala: Incyte Corporation: Membership on an entity's Board of Directors or advisory committees; Novartis: Honoraria, Membership on an entity's Board of Directors or advisory committees; Astellas: Honoraria; Celgene: Honoraria. Garcia Gutierrez: BMS: Consultancy, Honoraria, Research Funding; Pfizer: Consultancy, Honoraria, Research Funding; Incyte: Consultancy, Honoraria, Research Funding; Novartis: Consultancy, Honoraria, Research Funding. Osorio: Janssen, Abbvie, Roche: Consultancy. Sanchez: Janssen, Jazz Pharmaceuticals, Gilead, Novartis, Amgen: Consultancy. Martínez-López: Janssen, BMS, Novartis, Incyte, Roche, GSK, Pfizer: Consultancy; Roche, Novartis, Incyte, Astellas, BMS: Research Funding.

Introduction: asciminib is a first-in-class STAMP (Specifically Targeting the ABL Myristoyl Pocket) inhibitor that potently inhibits aberrant kinase activity of the BCR-ABL1 oncoprotein via allosteric binding. asciminib has shown high efficacy profile in heavily pretreated Chronic Myeloid Leukemia (CML) patients with an adequate safety profile in phase I and III clinical trials. However, data from the use of asciminib in real life setting are still scarce. Methods: We gathered real-life retrospective data from 49 patients with BCR-ABL1 positive CML treated with asciminib (mean dose: 40 mg twice daily) between October 2018 and July 2021 at 33 institutions. The indication of asciminib was made according to the criterion of the attending physician and the drug was granted by Novartis under a controlled access program. Molecular biology tests were performed according to ELN guidelines and BCR-ABL/ABL ratios were expressed as % IS in all centers. Treatment responses were calculated with the patients at risk at each specific time points. For the event free survival (EFS), the events were treatment discontinuation due to any reason, progression or death. Data collection followed the local regulations for observational studies. Results: Median time on asciminib was 11,69 months for the entire cohort. Patients' characteristics are displayed on Table 1. Most patients were heavily pretreated with at least 3 prior TKI lines in 45 patients (91,83%), 18 of them receiving prior Ponatinib. Switch to asciminib occurred due to intolerance in 32 patients and due to resistance in the remaining 17. Fifteen patients (30,61%) harbored mutations in BCR-ABL1 (3 with a T315 mutation). Regarding efficacy (Table 2), probability of reaching or maintaining previous responses were 94%, 45% and 21% for complete hematological response (CHR), complete cytogenetic response (CCyR) and major molecular response (MMR), respectively. Considering probabilities of improving previous response, rates were 40%, 42% and 33% for the same parameters. Probabilities to obtain CCyR and MMR in resistant and intolerant patients were 29% (4/14) vs 55% (6/11) and 27% (4/15) vs 52% (11/21), respectively. Amid the patients previously treated with Ponatinib, probabilities of reaching or maintaining previous response were 53% (9/17) and 35% (6/17) for CCyR and MMR respectively, and 30% (3/10), 23% (3/13) displayed improvement of response. Regarding responses in patients with mutations, 39% (5/13) achieved or maintained CCyR and 31% (4/13) MMR; whereas 20% (2/10) and 18% (2/11) improved such responses. Of the three patients with T315I mutation, one discontinued due to progression to advanced stages, and the rest maintained the previous response. With a median follow-up of 11,69 months, the estimated EFS was 80% (figure 1). In terms of safety (Table 3), the most frequent extra-hematological adverse events (AE) were: fatigue (16,2%), joint pain (13,5%) and nausea (8,1%), most of them grade 1-2. Grade 3-4 AE were observed in 10% of patient (fatigue (2), cholestasis enzyme elevation (1), hypertension (1), pancreatitis (1) and pericardial effusion (1)). Thrombocytopenia was shown as the most frequent AE (16,3%), with 6% of patients suffering from grade 3-4. Dose reduction was required in 15 patients (30,6%). After a median follow up of 51 weeks, 73,5% of the patients remained on treatment. Only fourteen patients discontinued treatment due to progression or loss of efficacy, whereas 6% of patients discontinuing treatment due to intolerance. Conclusions: The results presented are in line with the data obtained in clinical trials, positioning asciminib as a potential safe and efficacious treatment for CML patients with failure to several TKI lines. Figure 1 Figure 1. Disclosures Sanchez-Guijo: Novartis: Consultancy, Honoraria, Research Funding; Celgene/Bristol-Myers-Squibb,: Consultancy, Honoraria; Incyte: Consultancy, Honoraria; Pfizer: Consultancy, Honoraria; Takeda: Honoraria, Research Funding; Roche: Consultancy, Honoraria; Gilead: Consultancy, Honoraria; Amgen: Consultancy, Honoraria. Garcia Gutierrez: BMS: Consultancy, Honoraria, Research Funding; Novartis: Consultancy, Honoraria, Research Funding; Pfizer: Consultancy, Honoraria, Research Funding; Incyte: Consultancy, Honoraria, Research Funding.

BACKGROUND The rate of major arterial and venous thrombosis in primary myelofibrosis (PMF) and post-ET (PET) and post-PV (PPV) secondary myelofibrosis has been evaluated in a limited number of studies. In the present paper we describe the clinical epidemiology of thrombosis in a large series of patients with overt PMF and PPV/PET MF looking at the rate and risk factors. Moreover, we report findings on thrombosis rate in two cohorts of patients treated with Hydroxyurea (HU) or Ruxolitinib (Ruxo). METHODS Patients were registered in the European Registry for Myeloproliferative Neoplasms (ERNEST). This project, promoted by the European LeukemiaNet, is coordinated by FROM - Foundation for Research, Papa Giovanni XXIII Hospital, Bergamo (Italy) and supported by Novartis through a research collaboration . Patients were diagnosed in 6 Centers from Italy, Spain and Sweden, between Jan, 2001 and Dec, 2012, with the required follow-up information. Patients (n= 1010) with PMF (n=584, 59%), PET-MF (n=207, 20%) and PPV-MF (n=219, 21%) were evaluated for incident thrombosis as primary endpoint. Considering death as a competitive event, uni-and multivariate analyses were performed by applying Fine & Gray competing-risk regression models. RESULTS After a median follow-up of 3.8 years (IQR: 1.8-7.1) from diagnosis, 108 thromboses (10.7%) occurred, for an overall incidence rate of 2.0% pts-yr (95% CI: 1.7-2.5). Arterial thromboses were found in 50 patients (46.3%) including cerebral (n=21, 19.4%), myocardial infarction (n=13, 12.0%) and peripheral events (n=9, 8.3%). Venous thromboses were 58 (53.7%), of which 25 (23.0%) were DVT ± PE and 11 (10.2%) were splanchnic. Thrombosis rate was 1.91, 1.60 and 2.79% pts-yr in PMF, PET-MF and PPV-MF, respectively. In univariate analysis, factors significantly associated with an increased thrombotic risk in PMF were age (p=0.013) and the presence of the JAK2 mutation (p=0.003); in addition, a significant higher proportion of PMF patients at low and intermediate-1 vs intermediate-2 or high risk IPSS score, had thrombosis during the follow-up (p=0.008). In multivariate analysis, only JAK2 mutation retained statistical significance (SHR=3.12, 95% CI: 1.40-6.94, p=0.005). Conversely, neither in univariate nor in multivariable analysis, significant risk factors were not found.To investigate the possible interaction of IPSS score and JAK2 mutation we created a model whose results are presented in Fig. 1A: the cumulative incidence function (CIF) of thrombosis was significantly lower in patients with JAK2 wild-type and intermediate-2 or high IPSS score (CIF: 4% projected at 10 years; SHR=1 [reference category]), while patients at the highest risk for thrombosis harbored JAK2 mutation and were categorized at low or intermediate-1 by IPSS score (CIF: 20% projected at 10 years, SHR=7.13, p=0.008). Of note, thrombosis had a significant impact on mortality. After adjusting for sex, age, year of diagnosis, type of MF and IPPS, HR was 1.51, (95% CI. 1.15-1.98, p=0.003).The influence of drug exposure to incident thrombosis was investigated in two cohorts of 559 consecutive patients exposed to HU (n=470) or to Ruxo (n=89), median treatment 2.6 and 3.0 years, respectively. HU- compared to Ruxo-treated patients were older (median age 67 vs. 63 years, p=0.001), more frequently triple negatives (12% vs. 2%, p=0.036), less splenomegalic (spleen length >10 cm: 30% vs. 88%, p CONCLUSION IPSS score, in addition to the survival risk assessment, may be useful, if associated with the JAK2 mutation, to recognize patients at vascular risk and to suggest appropriate anti-thrombotic prophylaxis. The trend towards a benefit of Ruxo, compared to HU, warrants a study in larger case series. Figure 1 Figure 1. Disclosures Barbui: AOP Orphan: Membership on an entity's Board of Directors or advisory committees, Research Funding; Novartis: Membership on an entity's Board of Directors or advisory committees, Research Funding. Passamonti: Janssen: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Novartis: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Celgene: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; BMS: Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau; AbbVie: Speakers Bureau. Vannucchi: Incyte: Membership on an entity's Board of Directors or advisory committees; Novartis: Membership on an entity's Board of Directors or advisory committees, Other: Lectures; Celgene: Membership on an entity's Board of Directors or advisory committees, Other: Lectures; AbbVie: Membership on an entity's Board of Directors or advisory committees, Other: Lectures.

Summary The influence of driver mutations on leukaemic transformation was analysed in 1747 patients with polycythaemia vera or essential thrombocythaemia. With a median follow-up of 7·2 years, 349 patients died and 62 progressed to acute leukaemia or myelodysplastic syndrome. Taking death as a competing risk, CALR genotype was associated with a lower risk of transformation [subdistribution hazard ratio (SHR): 0·13, 95% confidence interval (CI): 0·2–0·9, P = 0·039], whereas JAK2 V617F showed borderline significance for higher risk (SHR: 2·05, 95% CI: 0·9–4·6, P = 0·09). Myelofibrotic transformation increased leukaemic risk, except in CALR-mutated patients. Next generation sequencing of 51 genes at the time of transformation showed additional mutations (median number: 3; range: 1–5) in 25 out of 29 (86%) assessable cases. Mutations (median: 1; range: 1–3) were detected in 67% of paired samples from the chronic phase. Leukaemia appeared in a JAK2 V617F negative clone in 17 (58%) cases, eleven of them being previously JAK2 V617F-positive. JAK2 V617F-mutated leukaemia was significantly associated with complex karyotype and acquisition of TP53 mutations, whereas EZH2 and RUNX1 mutations were more frequent in JAK2 V617F-negative leukaemia. Survival was longer in JAK2 V617F-unmutated leukaemia (343 days vs. 95 days, P = 0·003). In conclusion, CALR genotype is associated with a lower risk of leukaemic transformation. Leukaemia arising in a JAK2 V617F-negative clone is TP53 independent and shows better survival.

Background More than 50% of CML patients treated with ABL tyrosine kinase inhibitors (TKIs) obtain during treatment a Deep Molecular Response (DMR), defined as the presence of BCR-ABL1 transcript levels lower than 1/10000 (or MR4). Treatment discontinuation (TD) in CP-CML patients with stable DMR has proven successful in approximately half of cases, with relapse free survival (RFS) of 48-61% at 3 years. TD proved a safe option, since virtually all patients leukemia regains optimal control with TKI rechallenge, and treatment-free remission (TFR) is usually attempted outside clinical trials. The occurrence of tumor progression, i.e. the progression to Accelerated Phase/Blast Crisis (AP/BC) has been considered a rare event. However, reports document at least six cases of disease progression after TD, some of which were fatal. These observations raise concerns about the safety of TKI discontinuation, since now we can no longer consider this practice as completely immune from the risk of disease progression, a condition which dramatically changes the patient situation and perspective. Nevertheless, a precise quantification of the risk of progression in this setting has not been determined. Study Design and Methods The TFR-PRO project will monitor approximately 3000 CML patients in long term treatment and with stable and minimal residual disease (MR4 or better) followed at 28 centers in 5 different countries (US, Canada, Italy, Germany, Spain). Each center is expected to enroll approximately 100 patients. A total of 30000 person years will be collected. The following variables will be measured: time adjusted rates (TAR) of molecular relapse and of progression to AP/BC; progression free and overall survival; incidence of Serious Adverse Events (SAEs) and evaluation of Quality of Life indicators. Primary Objective To quantify the risk of progression to AP/BP, expressed as TAR, after TKI discontinuation in CML patients who undergo a first or subsequent TKI discontinuation attempt. This value will be compared to that obtained in a similar population of patients with the same characteristics who do not discontinue TKI treatment. Patients eligibility includes a history of at least 4 years of TKI treatment and at least 18 months of DMR. Events developing in patients after the end of discontinuation and TKI resumption will be considered linked to the discontinuation if they will develop within 36 months from the end of discontinuation. This rule will apply also to subsequent TD attempts. In case of a second or subsequent discontinuation attempt after the failure of a previous one (for molecular relapse), patients must have re-achieved a DMR with TKI therapy resumption and must keep DMR for at least 18 months before another TD. Collection of data will be retrospective and prospective, as each center will collect the data for 24 months. Patients who become eligible before the opening of this study will contribute to the retrospective cohort, while those who will enter after it will contribute to the prospective cohort. Patients who will become eligible before the opening of this study but will continue after it, will contribute to both cohorts. Sample size calculations were obtained assuming a contrast between risks of progression to AP or BP of 0.001% under treatment versus 0.1% under discontinuation (Figure 1). Study group classification will be defined as a binary non reversible time-varying factor where eligible patients are divided into two groups at the beginning of the follow-up depending on the presence or absence of discontinuation, and in the latter case may start discontinuation during the follow-up and thus change dynamically the study group classification. Descriptive statistics on the main end-point will be obtained by the "Simon-Makuch" version of the Kaplan-Meier curves and log-rank test. Exponential model will be used for the calculation of confidence intervals on rates. Flexible Poisson model and Cox model will be used for data analysis adjusting for potential prognostics factors. The dynamic nature of the study group classification will be handled by left truncation. The study was opened on July 24th. Eligible patients belonging to the prospective cohort will be entered in TFR-PRO between August 1st, 2020 and August 1st, 2021 while those in the retrospective cohort will be entered by November 1, 2020. Total duration of the study will be of 24 months. Disclosures Gambacorti-Passerini: Bristol-Myers Squibb: Consultancy; Pfizer: Honoraria, Research Funding. Assouline:Janssen: Consultancy, Honoraria, Speakers Bureau; AstraZeneca: Consultancy, Honoraria, Speakers Bureau; AbbVie: Consultancy, Honoraria, Speakers Bureau; F. Hoffmann-La Roche Ltd: Consultancy, Honoraria, Research Funding; Takeda: Research Funding; BeiGene: Consultancy, Honoraria, Research Funding; Pfizer: Consultancy, Honoraria. Pregno:Incyte-Italy,: Membership on an entity's Board of Directors or advisory committees, Other: conference reports; Novartis-Italy: Membership on an entity's Board of Directors or advisory committees, Other: conference reports; Pfizer-Italy: Membership on an entity's Board of Directors or advisory committees, Other: conference reports. le Coutre:Pfizer: Honoraria; Novartis: Honoraria; Incyte: Honoraria. Saussele:Incyte: Honoraria, Research Funding; Pfizer: Honoraria; Novartis: Honoraria, Research Funding; Bristol-Myers Squibb: Honoraria, Research Funding. Druker:EnLiven: Consultancy, Research Funding; Gilead Sciences: Consultancy, Membership on an entity's Board of Directors or advisory committees; GRAIL: Consultancy, Current equity holder in private company, Membership on an entity's Board of Directors or advisory committees; Henry Stewart Talks: Patents & Royalties; Iterion Therapeutics (formerly Beta Cat Pharmaceuticals): Membership on an entity's Board of Directors or advisory committees; Leukemia & Lymphoma Society: Research Funding; McGraw Hill: Patents & Royalties; Merck & Co: Patents & Royalties; Millipore (formerly Upstate Biotechnology): Patents & Royalties; MolecularMD (acquired by ICON): Consultancy, Current equity holder in publicly-traded company, Membership on an entity's Board of Directors or advisory committees; Novartis Pharmaceuticals: Membership on an entity's Board of Directors or advisory committees, Patents & Royalties, Research Funding; Oregon Health & Science University: Patents & Royalties; Patient True Talks: Consultancy; Pfizer: Research Funding; The RUNX1 Research Program: Membership on an entity's Board of Directors or advisory committees; Third Coast Therapeutics: Membership on an entity's Board of Directors or advisory committees; VB Therapeutics: Membership on an entity's Board of Directors or advisory committees; Vivid Biosciences: Membership on an entity's Board of Directors or advisory committees; ARIAD: Research Funding; Aptose Therapeutics Inc. (formerly Lorus): Consultancy, Current equity holder in publicly-traded company, Membership on an entity's Board of Directors or advisory committees; Amgen: Current equity holder in publicly-traded company, Membership on an entity's Board of Directors or advisory committees; ALLCRON: Consultancy, Membership on an entity's Board of Directors or advisory committees; Aileron Therapeutics: Membership on an entity's Board of Directors or advisory committees; Blueprint Medicines: Consultancy, Current equity holder in private company, Membership on an entity's Board of Directors or advisory committees; Bristol-Myers Squibb: Research Funding; Cepheid: Consultancy, Membership on an entity's Board of Directors or advisory committees; Dana-Farber Cancer Institute: Patents & Royalties.

Introduction: Ph-negative myeloproliferative neoplasms (MPNs) are a group of clonal stem-cell disorders with an elevated risk for thrombosis. Leukocytosis is a well-known risk factor for thrombosis. Neutrophils from MPN patients display features of activation. On stimulation, neutrophils produce neutrophil extracellular traps (NETs), which have been implicated in the pathogenesis of thrombosis. Myeloperoxidase-conjugated DNA levels (a specific NET marker) have been found increased in plasma of thrombotic MPN patients (Guy, A, ISTH 2019 OC 77.3). Ex vivo, activated neutrophils from JAK2V617F patients are primed to form NETs, diminishing under ruxolitinib treatment. Mice with conditional knock-in of JAK2V617F have increased NETs formation and thrombotic events. Inhibition of JAK/STAT signaling by ruxolitinib abrogated NETs formation and reduced thrombosis in this murine model (Wolach, O,Sci. Transl. Med. 2018). Thus, a link between JAK2V617F expression, NETs formation and thrombosis has been suggested (Wolach, O, 2018). It remains unclear whether, in MPN patients, JAK/STAT independent pathways are implicated in the NETs formation. With this aim, we explored the effects of different cytoreductors in NETs formation. Patients and Methods: In a multicentric study conducted at Hospital General Universitario Morales Meseguer (Murcia, Spain) and Hospital del Mar (Barcelona, Spain), EDTA plasma samples were collected from MPN patients (n=104). Patients include polycythemia vera (PV, n=35, all of them JAK2V617F), essential thrombocythemia [ET, n=47; 38 JAK2V617F, 4 CALRmut, 5 triple negative (TN)], myelofibrosis (MF, n=9; 4 JAK2V617F, 2 CALRmut, 3 TN), and unclassifiable MPN by WHO-2016 (MPN-u, n=13; 12 JAK2V617F, 1 CALRmut). Samples were collected at different time points following up the disease: at diagnosis or before any cytoreductive treatment, time 0, (n=100), less than 6 months of treatment (time 6; n=60), from 6 to 12 months of treatment (time 12; n=60), and from 12 to 24 months of treatment (time 24; n=49). Among the 104 patients, we had clinical information about treatment on 99 cases, included hydroxyurea (HU, n=69), ruxolitinib (n=15), IFN-α (n=2), and non-treated (n=13, all basal samples). We measured citH3-DNA complexes, as specific marker of NETs, by ELISA using rabbit anti-citH3 (Abcam) and peroxidase-conjugated anti-DNA antibody (Cell Death Detection ELISA). The absorbance at 405 nm (A405) was measured in a plate reader (Biotek®). Thus, we followed up the NETosis marker evolution with treatment over time. One-tailed and paired Wilcoxon test was applied and p Results: Overall, regardless of the treatment, we observed a reduction of citH3-DNA levels over time (Fig. 1A), being these significant between time 0 and times 6 and 12 (p=0.02 for both time-points), Importantly, patients treated with HU showed a substantial reduction of NETs in all time-points (Fig. 1B, left), which was statistically significant between times 0 and 6 (p=0.03) and between times 0 and 24 (p=0.02). Although in patients treated with ruxolitinib, the citH3-DNA levels seem to be reduced at time 12, the difference was not significant (Fig. 1B, right), probably because of the small sample size. Regarding the MPN phenotype, decrease of citH3-DNA levels over time was only observed in PV patients (Fig. 1C, left), specially at time 12 (p=0.03). In contrast, under cytoreductive treatment, ET patients did not show significant differences in NETs levels over time (Fig. 1C, middle). In MF, there were not enough samples to obtain a clear conclusion (Fig. 1C, right). Regarding the driver gene mutations, we detected a significant decrease in the citH3-DNA levels in JAK2V617F patients (Fig. 1D, left), specifically between basal time and times 6 and 12 (p Conclusions: Our results showed that hydroxyurea reduces NETosis levels in plasma from MPN patients, suggesting that JAK-STAT independent pathways could be implicated in the NET formation. Hydroxyurea could decrease thrombosis in MPN patients, not just reducing the number of functionally abnormal cells in peripheral blood, but also by abrogating NET formation. Acknowledgements: This study was supported in part by ISCIII (PI18/00316 & PI16/0153) & Fundación Séneca (20644/JLI/18). Disclosures Bellosillo: Qiagen: Consultancy, Speakers Bureau; Roche: Consultancy, Research Funding, Speakers Bureau.

Background Direct oral anticoagulants (DOACs) have emerged as a treatment of choice in patients with chronic atrial fibrillation (AF) or for secondary prevention of venous-thromboembolism (VTE). In myeloproliferative neoplasms (MPN) very small series have been reported and robust data reporting the safety/efficacy profile of these drugs is not available. We conducted an international, multi-country, retrospective study involving 19 hematologic centers from Europe, US and Canada, with the aim to describe in a large cohort of MPN patients the incidence of thrombosis and bleeding complications associated with DOAC use in real word clinical practice. Methods Centers reported in an electronic CRF data on 442 patients (M/F: 221/221; median age: 65 years) with a WHO diagnosis of polycythemia vera (PV, n=178), essential thrombocythemia (ET, n=172) and primary myelofibrosis (PMF, n=92) who had received DOACs (Rivaroxaban n=187; Apixaban n=157; Dabigatran n=50; Edoxaban n=48) for either primary and secondary antithrombotic prophylaxis in atrial fibrillation (AF, n=203) or secondary prophylaxis of venous thromboembolism (VTE, n=239). Eighty-two patients (18.6%) shifted to DOAC after a previous exposure to a vitamin K antagonist (VKA) mainly due to patient preference (8.4%), bleeding/thrombosis (5.2%) or INR instability (4.1%). In 60 patients, DOAC was discontinued after a median duration of 1.1 years; reasons included completion of a pre-determined duration (2.9%), patient decision (0.9%), major bleeding (2.5%) or thrombosis (2.9%), minor bleeding (0.9%), thrombocytopenia (2.0%), surgery (0.9%), or other (0.5%). Results Median time from MPN diagnosis to DOAC initiation was 4.4 years (range: 0-34.7 years). Concomitant therapies included antiplatelet agents (31%) and cytoreductive drugs in 90% (hydroxyurea in 87%of cases). After a median follow-up of 1.83 years, 32 major thrombotic events (rate: 3.3% pts/yr) and 26 major bleeding events (rate: 2.6% pts/yr) were reported. 1. AF. Ten thrombotic events (rate: 2.1% pts/yr) occurred in patients receiving DOACs: 4 TIA, 3 MI and 3 DVT of the lower extremities (LE); the rate was remarkably different in primary prevention (1.5% pts/yr) vs. secondary prophylaxis (i.e. after a previous thrombosis, mainly arterial: 4.6% pts/yr). This rate was almost double that reported in secondary prophylaxis in non-MPN population in randomized clinical trials (RCTs) (2.1-3.2% pts/yr). Previous arterial thrombosis was the only significant risk factor for recurrences in this subset (HR: 3.89, p=0.035). 2. VTE. Twenty-two recurrences while receiving DOACs were reported (5 arterial, 10 DVT of the LE +/- PE, 3 splanchnic vein and 4 others venous; rate: 4.5% pts/yr) and irrespective of initial site of thrombosis and type of DOACs. This rate was similar to MPN patients receiving VKAs (5.3% pts/yrs - De Stefano V et al, Leukemia 2016) but higher than in non-MPN population in RCTs (1.4-1.9% pts/yr). In univariate analysis, significant factors for recurrences were: previous arterial thrombosis (HR: 3.55, p=0.023), hypertension (HR: 2.88, p=0.021) and diabetes (HR: 3.33, p=0.018). 3. Among 26 major bleeding events, 12 were gastrointestinal, 7 intramuscular, 1 CNS and 6 in other sites. The overall rate was 2.6% patients/year, which is comparable to that reported in MPN patients under VKA (2.4% pt/yrs, De Stefano V et al, ibidem) and in non-MPN population of RCTs (1.60-3.11% pt/yrs). The frequency of major bleeding was similar in AF (3% pt/yrs) and VTE (2.3% pt/yrs) setting. In univariate analysis, significant risk factors were PMF diagnosis (HR: 2.95, p=0.007) and the use of Dabigatran in comparison to the other DOACs (HR: 2.91, p=0.016) whereas no increase was due to antiplatelet drugs. Conclusions This is the largest observational study describing vascular events in MPN patients receiving DOACs for prevention of thrombosis in AF or secondary prevention of VTE. Overall, the rate of re-thrombosis is similar to that reported with warfarin in MPN and double the rate of non-MPN population. The highest rate was found in patients with a previous history of arterial thrombosis and with cardiovascular risk factors. In regard to bleeding, we highlight the significant bleeding tendency in PMF and treatment with Dabigatran. In conclusion, the risk/benefit profile of DOACs in MPN is similar to that of Warfarin. Disclosures Barbui: AOP-Orphan: Membership on an entity's Board of Directors or advisory committees, Research Funding; Novartis: Membership on an entity's Board of Directors or advisory committees, Research Funding. De Stefano:Novartis: Other: Personal fee, Research Funding; Amgen: Other: Personal fee; Bayer: Other: Non-financial support; Celgene: Other: Non-financial support, personal fee; Janssen Cilag: Other: Non-financial support. Vannucchi:AbbVie: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Blueprint: Membership on an entity's Board of Directors or advisory committees; Incyte: Membership on an entity's Board of Directors or advisory committees; Novartis: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Celgene/BMS: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau. Palandri:Novartis: Consultancy, Honoraria. Harrison:Celgene: Honoraria, Research Funding, Speakers Bureau; Gilead Sciences: Honoraria, Speakers Bureau; Incyte Corporation: Speakers Bureau; Janssen: Speakers Bureau; Novartis: Honoraria, Research Funding, Speakers Bureau; Shire: Honoraria, Speakers Bureau; AOP Orphan Pharmaceuticals: Honoraria; Promedior: Honoraria; Roche: Honoraria; Sierra Oncology: Honoraria; CTI Biopharma Corp: Honoraria, Speakers Bureau. Griesshammer:Novartis: Honoraria, Speakers Bureau; AOP Orphan: Honoraria, Speakers Bureau; Celgene: Honoraria, Speakers Bureau; CTI: Honoraria, Speakers Bureau; Shire: Honoraria, Speakers Bureau. Koschmieder:Celgene/BMS: Honoraria, Membership on an entity's Board of Directors or advisory committees, Other: travel support, Research Funding; Janssen: Honoraria, Membership on an entity's Board of Directors or advisory committees, Other: travel support, Research Funding; Geron Corporation: Honoraria, Membership on an entity's Board of Directors or advisory committees, Other: travel support; Incyte/Ariad: Honoraria, Membership on an entity's Board of Directors or advisory committees, Other: travel support; Roche: Honoraria, Membership on an entity's Board of Directors or advisory committees, Other: travel support; CTI Biopharma: Honoraria, Membership on an entity's Board of Directors or advisory committees, Other: travel support; Novartis: Honoraria, Membership on an entity's Board of Directors or advisory committees, Other: travel support, Research Funding; Pfizer: Honoraria, Membership on an entity's Board of Directors or advisory committees, Other: travel support; Bayer: Honoraria, Membership on an entity's Board of Directors or advisory committees, Other: travel support; AOP Pharma: Honoraria, Membership on an entity's Board of Directors or advisory committees, Other: travel support, Research Funding; Promedior: Other. Benevolo:Amgen: Honoraria; Celgene: Honoraria; Novartis: Honoraria. Gupta:Pfizer: Consultancy; Novartis: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Sierra Oncology: Consultancy, Membership on an entity's Board of Directors or advisory committees; Bristol MyersSquibb: Honoraria, Membership on an entity's Board of Directors or advisory committees; Incyte: Honoraria, Research Funding. Mascarenhas:Incyte, Kartos, Roche, Promedior, Merck, Merus, Arog, CTI Biopharma, Janssen, and PharmaEssentia: Other: Research funding (institution); Celgene, Prelude, Galecto, Promedior, Geron, Constellation, and Incyte: Consultancy.

Introduction: Asciminib is a new BCR-ABL1 inhibitor that differs from previous tyrosine kinase inhibitors (TKIs) in that it does not bind to the ATP-binding site of the kinase. Data from different clinical trials has shown an adequate safety and efficacy profile in chronic myeloid leukemia (CML) patients failing previous TKIs. However, no findings have been communicated in real life experience. The aim of our study is to present first results of asciminib in CML patients failing previous TKIs under the current compassionate use program. Methods: We retrospectively collected data from 31 patients treated with asciminib in 25 centers under compassionate use program. Data collecting was performed between October 2018 and June 2020. Patients baseline characteristics are shown in table 1. Most patients were heavily pretreated with 28 patients receiving 3 or more TKIs previous to asciminib. Eleven patients (35.5%) had been treated with ponatinib at some point throughout the disease. Twelve patients showed BCR-ABL1 mutations (only 1 case with T315I mutation). Switch to asciminib was due to intolerance in 22 patients and due to resistance in the remaining 9. Median dose of asciminib was 80mg per day (40mg every 12 hours). Treatment responses were evaluated according to European Leukemia Net recommendations. Data compilation and analysis were performed with REDCap Software and IBM SPSS (Version 25.0). Results: Median time on asciminib for the entire cohort was 35 weeks. Regarding toxicities, 13 patients (42%) experienced mild extra-hematological side effects (grade 1-2) being the most frequent fatigue (19%), joint pain (16%) and nausea (9%). Four patients (12,9%) showed severe (grade 3-4) extra-hematological events: fatigue, hepatotoxicity, hypertension and pericardial effusion (1 patient each). Three patients (9,7%) suffered from grade 4 thrombocytopenia, 2 of them associating grade 4 neutropenia. All toxicities according to previous TKIs adverse effects as well as cross-intolerance data is shown in table 2. Dose reduction had to be carried out in 9 patients (29%), 7 of those with temporary treatment interruptions; most owing to hematological adverse effects. In terms of efficacy (Graph 1), probability of reaching or at least maintaining previous response was 100%, 61.3% and 35.5% for complete hematological response (CHR), complete cytogenetic response (CCyR) and major molecular response (MMR), respectively. Regarding probabilities to improve previous responses, rates of CCyR and MMR were, respectively, 22,2% (2/9) and 22,2% (2/9) for resistant patients and 44% (4/9) and 62,5%. (10/16) for intolerant group. Amid the 11 patients previously treated with ponatinib, 3 patients (27,3%) showed improvement of response achieving at least MMR, 2 of them from the TKI-intolerant group and 1 from the TKI-resistant group. The median follow-up time was 40 weeks, after which 27 patients (87.1%) continued with asciminib. Treatment cessation happened in 2 patients due to progression to blastic phase and in 2 patients due to lack of efficacy. No patients discontinued due to side effects. Conclusion: The data presented, similar to that known from clinical trials, supports the use of asciminib in routine clinical practice in CML patients failing to previous TKIs. Disclosures Garcia-Gutiérrez: Novartis: Consultancy, Other: Travel, Accommodation, Expenses, Research Funding; Bristol-Myers Squibb: Consultancy, Other: Travel, Accommodation, Expenses, Research Funding; Pfizer: Consultancy, Other: Travel, Accommodation, Expenses, Research Funding; Incyte: Consultancy, Other: Travel, Accommodation, Expenses, Research Funding.

Patients with Philadelphia-negative myeloproliferative neoplasm (MPN) are prone to the development of second cancers, but the factors associated with these events have been poorly explored. In an international nested case-control study, we recruited 647 patients with carcinoma, nonmelanoma skin cancer, hematological second cancer, and melanoma diagnosed concurrently or after MPN diagnosis. Up to 3 control patients without a history of cancer and matched with each case for center, sex, age at MPN diagnosis, date of diagnosis, and MPN disease duration were included (n = 1234). Cases were comparable to controls for MPN type, driver mutations and cardiovascular risk factors. The frequency of thrombosis preceding MPN was similar for cases and controls (P = .462). Thrombotic events after MPN and before second cancer were higher in cases than in controls (11.6% vs 8.1%; P = .013), because of a higher proportion of arterial thromboses (6.2% vs 3.7%; P = .015). After adjustment for confounders, the occurrence of arterial thrombosis remained independently associated with the risk of carcinoma (odds ratio, 1.97; 95% confidence interval, 1.14-3.41), suggesting that MPN patients experiencing arterial events after MPN diagnosis deserve careful clinical surveillance for early detection of carcinoma. This study was registered at www.clinicaltrials.gov as NCT03745378.

Introduction Malignancy can be heralded by unprovoked venous thromboembolism (VTE) but also by arterial thrombosis. To date it is unknown whether this association is present also in myeloproliferative neoplasms (MPN), in which arterial thrombosis is more frequent that venous thrombosis and solid tumors are reported with an increased frequency. The MPN-K nested case-control study addressed the impact of cytoreductive drugs on the risk of developing second cancer in MPN patients (Barbui T et al, Leukemia 2019); here we re-examined the study database to evaluate the frequency and type of vascular complications in MPN patients with second cancer excluding leukemia and to establish whether arterial and venous thrombosis during follow-up after diagnosis of MPN could predict the occurrence of a second cancer. Patients and methods Cases were patients with second cancer diagnosed concurrently or subsequent to the diagnosis of MPN. Controls were MPN patients without second cancer. For each case with second cancer, up to 3 cancer-free controls were matched by each center for sex, age at MPN diagnosis, date of MPN diagnosis, and MPN disease duration. Each set consisting of one case and their matched-controls had a similar observational period (from MPN diagnosis until the index date of diagnosis for the second cancer). The study included 647 cases with second cancer (carcinoma, non-melanoma-skin cancers, hematological secondary cancer and melanoma). The most frequent category was carcinoma (n=426, 65.8%). Cases were comparable with the 1,234 matched controls for demographics, type of MPN, and exposure to potential confounders such as mutational profile, abnormal karyotype and cardiovascular risk factors. The thrombotic events of interest were ischemic stroke, transient ischemic attacks, acute coronary syndromes, peripheral arterial thrombosis, deep venous thrombosis (including thrombosis of cerebral and splanchnic veins) and pulmonary embolism. Thrombosis had to be concurrent with or in the 2 years before MPN diagnosis or occurring after MPN diagnosis. The cumulative incidence of either arterial or venous thrombosis from MPN diagnosis was estimated by the Kaplan-Meier method and was compared between cases and controls using the log-rank test. A conditional logistic regression model estimated the Odds Ratio (OR) with 95% Confidence Interval (CI) of second cancer associated with the occurrence of thrombosis before/at diagnosis of MPN and during follow-up. Other covariates were patient age, cardiovascular risk factors, the JAK2V617F mutation, and treatment during follow-up. Results Approximately 20% of either MPN cases or controls had thrombosis before MPN or at diagnosis (19.8% vs. 21.1%, respectively, p=0.462). After a median observation time from diagnosis of MPN to an index date of 4.5 years (interquartile range 1.5-8.2) in cases and 3.7 years (interquartile range 1.5-7.5) in controls, cases showed a percentage of thrombosis higher than in controls (75/647, 11.6% vs. 100/1234, 8.1%, respectively, p=0.013). Approximately one-third of thrombosis preceding cancer occurred in the 12 months before the diagnosis of second cancer (22/75, 29.3%). The excess of thrombosis in cases was due to a higher frequency of arterial thrombosis (6.2% vs. 3.7%, p=0.015), whereas no significant difference was found for venous thrombosis (5.4% vs. 4.3%, p=0.277). While the cumulative incidence of venous thrombosis over time was similar among cases and controls (p=0.864), the cumulative incidence of arterial thrombosis was higher in cases with second cancer (p=0.006) (Figure 1). The excess of arterial thrombosis after MPN diagnosis was limited to cases with carcinoma (6.8% vs 3.9%, p=0.027). In a multivariable model, arterial thrombosis during the follow-up was confirmed to be an independent predictor factor for carcinoma, with an odds ratio of 1.97 (95%CI 1.14-3.41, p=0.015). Conclusions. These findings reveal an association of arterial thrombosis with subsequent second cancer (namely carcinoma) in MPN patients. A possible biological plausibility for this link may be related to an underlying common pathogenic mechanism such as an aberrant inflammatory response consistently found in MPN. This observation may have practical implications and suggests careful clinical surveillance for early diagnosis of second cancer in MPN patients with arterial thrombosis during the follow-up. Disclosures Palandri: Novartis: Consultancy, Honoraria. Iurlo:Novartis: Other: Speaker Honoraria; Incyte: Other: Speaker Honoraria; Pfizer: Other: Speaker Honoraria. Bonifacio:Incyte: Honoraria; Novartis: Honoraria; Amgen: Honoraria; Pfizer: Honoraria; BMS: Honoraria. Rumi:novartis: Honoraria, Research Funding. Elli:Novartis: Membership on an entity's Board of Directors or advisory committees. Lunghi:Pfizer: Honoraria; Novartis: Honoraria; Incyte: Honoraria. Benevolo:Novartis Pharmaceuticals: Consultancy. McMullin:Italopharma: Membership on an entity's Board of Directors or advisory committees; Novartis: Honoraria, Speakers Bureau; Daiko Sanyo: Membership on an entity's Board of Directors or advisory committees. Griesshammer:Novartis: Consultancy, Honoraria, Speakers Bureau. Vannucchi:CTI: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Incyte: Membership on an entity's Board of Directors or advisory committees; Italfarmaco: Membership on an entity's Board of Directors or advisory committees; Novartis: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Celgene Corporation: Membership on an entity's Board of Directors or advisory committees. Rambaldi:Pfizer: Consultancy, Speakers Bureau; Novartis: Consultancy, Speakers Bureau; Celgene: Consultancy, Speakers Bureau; Amgen: Consultancy, Speakers Bureau.

We conducted a large international nested case-control study including 1881 patients with Philadelphia-negative myeloproliferative neoplasms (MPN). Cases (n = 647) were patients with second cancer (SC: carcinoma, non-melanoma skin cancer, hematological second cancer, and melanoma) and controls (n = 1234) were patients without SC, matched with cases for sex, age at MPN diagnosis, date of MPN diagnosis, and MPN disease duration. The aim was to evaluate the risk of SC after exposure to cytoreductive drugs. Patients exposed to hydroxyurea (HU) (median: 3 years) had a risk of SC similar to unexposed patients (OR = 1.06, 95% CI 0.82-1.38). In contrast, in cancer-specific stratified multivariable analysis, HU had two-fold higher risk of non-melanoma (NM) skin cancer (OR = 2.28, 95% CI 1.15-4.51). A significantly higher risk of NM-skin cancer was also documented for pipobroman (OR = 3.74, 95% CI 1.00-14.01), ruxolitinib (OR = 3.87, 95% CI 1.18-12.75), and for drug combination (OR = 3.47, 95% CI 1.55-7.75). These three drugs did not show excess risk of carcinoma and hematological second cancer compared with unexposed patients. Exposure to interferon, busulfan, and anagrelide did not increase the risk. In summary, while it is reassuring that no excess of carcinoma was documented, a careful dermatologic active surveillance before and during the course of treatments is recommended.

Over half of chronic myeloid leukemia (CML) patients in deep molecular response do not lose the major molecular response (MMR) after stopping treatment with tyrosine kinase inhibitors (TKI). This strategy is safe in clinical trials, but its applicability in the real-life setting remains unsettled. We describe the outcomes after TKI discontinuation in a nationwide series of 236 CML patients. Median follow-up from treatment discontinuation was 21.5 months and 5 patients died from CML-unrelated causes. TKI therapy was reinitiated due to MMR loss (n = 52), increase ≥ 1 log in BCR-ABL transcript level without losing MMR (n = 12), patient preference (n = 2), and withdrawal syndrome (n = 1). Treatment-free remission rate at 4 years was 64% (95% confidence interval, CI: 55%–72%). Cumulative incidence of molecular recurrence at 3 years was 33% (95% CI: 26%–38%). TKI treatment for n = 196), MR4 (n = 15), MMR (n = 14), complete cytogenetic response (n = 10), and other (n = 1). A significant increase in Hb and cholesterol levels was observed after imatinib withdrawal. Our results demonstrate that TKI treatment discontinuation is feasible in real-life clinical practice.

Mutations in JAK2 or CALR are observed in patients with myeloproliferative neoplasms (MPN). To get further insight in the dynamics of the mutant clone, we assessed the mutant allele burden in hematopoietic stem cells (HSCs), hematopoietic progenitor cells (HPCs) and granulocytes from 138 patients [51 polycythemia vera (PV), 58 essential thrombocythemia (ET) and 29 myelofibrosis (MF)]. CALR-mutated ET patients harbored a higher mutant load at progenitor level than JAK2V617F-positive ET (HSCs: 39.9% vs 7.5% p

Performance of the myelofibrosis secondary to PV and ET-prognostic model (MYSEC-PM) in a series of 262 patients from the Spanish registry of myelofibrosis

Prognostic models are widely used in clinical practice for transplant decision-making in myelofibrosis (MF). We have compared the performance of the International Prognostic Scoring System (IPSS), dynamic IPSS (DIPSS), and DIPSS-plus in a series of 544 patients with primary or secondary MF aged