Treatment of Ropeginterferon Alpha-2b Achieves Hematologic Remission and Molecular Response in Patients with Hydroxyurea- and/or Anagrelide-Resistant/Intolerant Myeloproliferative Neoplasms

Background: Ropeginterferon alpha-2b (Ropeg) is a novel pegylated interferon-alpha approved for the treatment of polycythemia vera (PV) in Europe and Taiwan. Prior to its approval in Taiwan, the major options for patients with myeloproliferative neoplasms (MPNs) included hydroxyurea (HU) and/or anagrelide. Patients who are HU/anagrelide resistant/intolerant have limited options, as ruxolitinib is not subsidized by the national health insurance in Taiwan for PV. In 2017, the manufacturer provided a compassionate use program (CUP) for patients who were HU and/or anagrelide resistant/intolerant. Herein, we assessed the efficacy and safety of Ropeg in 20 MPN patients. Methods: To be eligible, patients must be resistant or intolerant to currently available therapies for MPN in Taiwan, mainly HU and anagrelide. Patients with autoimmune disorders, psychiatric illness, and acute/chronic infections were excluded. An accelerated dosing regimen was used, starting from 250 µg, and increased by 100 µg every two weeks until it reached the target dose of 500 µg, if no self-reported discomforts or abnormalities in biochemical or hematological profiles were observed. Efficacy assessments included hematologic parameters, phlebotomy need, and JAK2V617F allele burden. Hematologic remission was defined as platelets ≤400 x 10^9/L and white blood cells <9.5 x 10^9/L for essential thrombocythemia (ET), and platelets ≤400 x 10^9/L, white blood cells <10 x 10^9/L, and hematocrit <45% with no phlebotomy in the past 3 months for PV. Molecular response was defined as a reduction in JAK2V617F allele burden of at least 50% from baseline if baseline value was less than 50%, and a reduction of at least 25% from baseline if the baseline level was at least 50%. Each case was independently reviewed and approved for the use of Ropeg by both Institutional Review Board and the Ministry of Health and Welfare in Taiwan. Results: A total of 20 patients received treatment, which included 14 PV, 4 ET, 1 post-ET myelofibrosis (MF), and 1 pre-fibrotic primary MF (Table 1). There were 12 female and 8 male patients with a median age of 56.1 years old. Of these 20 patients, 18 had JAK2V617F mutation and 5 had a history of thrombosis. Of the 18 ET and PV patients, 13 achieved hematologic remission. The ET patients seemed to achieve hematologic remission faster than PV patients (19.3 vs. 33.2 weeks). Of the 18 patients with JAK2V617F mutation, 7 PV patients and 1 post-ET MF patient achieved molecular response, which took a median of 46 weeks after Ropeg treatment. Reduction in JAK2V617F allele burden was observed in 12 patients. One MF patient discontinued treatment due to disease progression. Another PV patient discontinued treatment due to acute myeloid leukemia transformation, although after treatment, the patient returned to PV state and continued Ropeg treatment. Overall, the drug was well tolerated, as most of the treatment-related adverse events (AEs) were mild to moderate. The AE profile was consistent with those from the phase 3 PROUD/CONTI-PV study. There were no unbearable side effects that led to treatment discontinuation. Conclusion: Our study provided evidence in the efficacy and safety of Ropeg for the treatment of HU-/anagrelide-resistant/intolerant MPNs. Hematologic remission was observed in ET and PV patients, whereas molecular response was observed in only PV patients, possibly due to the small sample size of ET patients. Our experience with Ropeg suggests it to be a promising option for the treatment of MPNs with drug-resistance/intolerance. Figure 1 Figure 1. Disclosures Chen: PharmaEssentia: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Amgen, Celgene, Novartis, and Panco Healthcare: Honoraria. Shih: PharmaEssentia Co: Consultancy, Membership on an entity's Board of Directors or advisory committees; Celgene Ltd: Research Funding; Ltd: Research Funding; Novartis: Research Funding. OffLabel Disclosure: Ropeginterferon alfa-2b is a novel interferon alpha indicated for the treatment of polycythemia vera in Europe and in Taiwan. This abstract describes the use of this agent for the treatment of myeloproliferative neoplasm patients with hydroxyurea/anagrelide resistance/intolerance.

Polycythemia Vera Patients Respond Better to Ropeginterferon Alfa-2b Than HU/BAT Irrespective of Pretreatment or Mutational Status; Results from 5 Years' Treatment in a Randomized, Controlled Setting in the PROUD-PV/Continuation-PV Trials

Introduction: Ropeginterferon alfa-2b (BESREMi®), a novel pegylated interferon with an extended half-life, was approved in Europe for treatment of patients with PV based on results from the phase 3 PROUD-PV and CONTINUATION-PV trials. Ropeginterferon alfa-2b treatment is recommended in hydroxyurea (HU) naïve patients as well as in those who have previously received HU. Therefore, treatment response was analyzed by prior HU treatment status, and the influence of baseline JAK2V617F allele burden and additional mutations - which may increase over time during non-disease modifying treatment - was explored. Methods: In PROUD-PV, patients aged ≥18 years, diagnosed with PV according to WHO 2008 criteria, and either cytoreduction-naïve or HU-pre-treated (for <3 years, without intolerance or resistance) were randomized 1:1 to receive ropeg or HU at individualized doses. After 12 months' treatment, patients could roll over into CONTINUATION-PV and patients in the HU arm were permitted to switch to best available treatment (BAT). After 5 years' treatment, complete hematologic response (CHR) and molecular response defined by modified ELN criteria were assessed in patients enrolled in the extension study CONTINUATION-PV (N=171). Sub-group analyses were performed by prior HU treatment, JAK2V617F allele burden category (≤50% or>50%), and in patients with available data (N=159), by the presence of non-driver mutations (TruSight™ Myeloid Panel, Illumina) or chromosomal aberrations (Affymetrix SNP6.0 array) at baseline. Results: After 5 years of treatment with ropeginterferon alfa-2b, high rates of CHR were sustained in both HU-naïve and HU pre-treated patients (53.1% and 61.3%, respectively), whereas in the control arm, the CHR rate was lower among HU pre-treated patients (36.0% compared to 48.0% for HU-naïve patients). Molecular response rates at 5 years in HU naïve and pre-treated patients were 71.4% and 64.5% respectively in the ropeginterferon alfa-2b arm and 26.0% versus 12.5% respectively in the control arm. Rates of adverse events (AEs), treatment-related AEs, serious AEs, and AEs leading to discontinuation were similar between the subgroups regardless of HU pre-treatment. Similar CHR rates were observed at 5 years irrespective of baseline JAK2V617F allele burden category (ropeginterferon alfa-2b arm: 57.1% versus 53.1% for allele burden ≤50% or >50%, respectively; control: 46.9% versus 38.5%, respectively). The molecular response rate in the ropeginterferon alfa-2b arm was higher among patients with baseline allele burden >50% (84.4% versus 61.3% for allele burden ≤50%); in the control arm there was no difference in molecular response rates between the allele burden subgroups (23.1% versus 20.8%, respectively). Of interest, the presence of non-driver mutations or chromosomal aberrations at baseline had no apparent influence on molecular response rates to ropeginterferon alfa-2b (64.5% compared with 70.7% in patients without these genetic abnormalities). Conclusion: High hematologic and molecular response rates in both HU-pretreated and HU-naïve patients and in those with more advanced JAK2V617F burden suggest that ropeginterferon alfa-2b is also a suitable treatment option in patients switching from HU. Disclosures Gisslinger: AOP Orphan Pharmaceuticals GmbH: Other: Personal fees, Research Funding; Novartis: Other: Personal fees, Research Funding; PharmaEssentia: Other: Personal fees; MyeloPro Diagnostics and Research: Other: Personal fees; Janssen-Cilag: Other: Personal fees; Roche: Other: Personal fees; Celgene: Other: Personal fees. Klade: AOP Orphan Pharmaceuticals GmbH: Current Employment. Pylypenko: Communal nonprofit enterprise "Cherkasy regional oncology dispensary of Cherkasy oblast council: Current Employment. Mayer: AOP Orphan Pharmaceuticals GmbH: Research Funding. Krejcy: AOP Orphan Pharmaceuticals GmbH: Current Employment. Empson: AOP Orphan Pharmaceuticals GmbH: Current Employment. Hasselbalch: Novartis, AOP Orphan: Consultancy, Other: Advisory Board. Kralovics: AOP Orphan Pharmaceuticals GmbH: Other: Personal fees; PharmaEssentia: Other: Personal fees; Qiagen: Other: Personal fees; Novartis: Other: Personal fees; MyeloPro Diagnostics and Research: Current holder of individual stocks in a privately-held company. Kiladjian: Novartis: Membership on an entity's Board of Directors or advisory committees; 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; Incyte Corporation: 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; PharmaEssentia: Other: Personal fees; Taiho Oncology, Inc.: Research Funding.

Environmental, Lifestyle Risk Factors and Host Characteristics Associated with Philadelphia Negative Myeloproliferative Neoplasm: A Systematic Review

Introduction: Myeloproliferative Neoplasms (MPNs) are group of clonal hematopoietic stem cell (HSC) disorders characterised by overproduction of myeloid cells and are associated with an acquired genetic mutation of JAK2V617F. The 2008 WHO MPNs classification grouped the related disorders naming them Philadelphia negative MPNs. These included polycythemia vera, essential thrombocythemia, pre-fibrotic myelofibrosis and primary myelofibrosis which are the focus of this review. The etiology of MPNs remains unknown. Epidemiological studies have indicated there are associations between environmental, lifestyle factors and host characteristic with pathogenesis of MPNs. The aim of this review is to summarize all published data investigating smoking, obesity, gender and exposure to benzene as contributing risk factors and establish their association with developing MPNs. Methods: Medline, Embase, Pubmed databases were systematically searched for relevant published articles with date restrictions of March 2003 to March 2020. The published studies using epidemiological study designs i.e. case control, cohort and cross-sectional studies were identified. Scanning of reference lists and the grey literature was also undertaken. Articles written in English language were included. This review followed the Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA) reporting guideline. Manual review of filtered records excluded inappropriate publications. Two investigators evaluated the full text of selected articles independently analysed the content qualitatively using the Newcastle-Ottawa Scale. Results: A total of 23 published articles met the inclusion criteria, reporting data on the impact of smoking and obesity, the effects of exposure to benzene and gender on MPNs pathogenesis. A significant association was found between smoking and development of MPNs explained by the substantial increase in the levels of several proinflammatory mediators and systematic oxidative stress causing hyperstimulation of myeloid compartments. The upregulation of JAK-STAT and NF-kB signalling pathway and several transcription factors in patients with MPNs who smokers are have been confirmed. Subsequently, these changes facilitate the clonal expansion of hematopoietic stem cells with JAK2V617F mutations. The literature did not confirm any significant association between obesity and risk of developing MPNs, but it cannot be ruled out as an contributing risk factor. The consequences of obesity have been explained in terms of changes in metabolic, endocrinologic, immunologic, and inflammatory systems which may lead to increase in the cell proliferation, cell mutation rate, dysregulate gene function, disturb DNA repair or induce epigenetic changes favouring the induction of neoplastic transformation. There is some evidence in the literature that in individuals exposed to benzene, there is a stimulation of erythropoietic progenitor cells with cytokine independent growth compared to non-exposed individuals. This spontaneous growth of erythroid progenitor cells is one of the hallmarks of MPNs but evidence to prove this hypothesis is uncertain. No strong association was found between exposure of benzene and MPNs but further investigation on effects of increased levels and duration of exposure will be beneficial. Host characteristics such as gender as contributing factors associated with MPNs has been explored in several studies. Gender has been classified as an independent modifier in JAK2V617F allele burden which influences genotype and clonal expansion resulting into allele burden variability, hence, partly responsible for to the differences in the development of the disease between males and females. Conclusion: The important role of predisposing factors such as environmental, lifestyle risk factors and host characteristic in the pathogenesis of MPNs cannot be eliminated. The significant association between smoking and developing MPNs has been confirmed. Gender can be classified as an independent modifier in JAK2V617F allele burden reflecting on the phenotypic heterogeneity of MPNs. The relationship between obesity and exposure to benzene with MPNs developments has not been established yet. The results from this review proposes a large, well-designed epidemiological research exploring these contributing factors. Figure 1 Figure 1. Disclosures No relevant conflicts of interest to declare.

Ruxolitinib for the Treatment of Polycythemia Vera: Response on Alternative Dose Versus Standard Dose

The polycythemia vera (PV) is a chronic myeloproliferative neoplasm characterized by increased hematocrit (HCT), elevated white-cell and platelet counts and splenomegaly. The most commonly used first line cytoreductive agent is hydroxyurea (HU). However, some patients have an inadequate response or have inacceptable side effects from HU. Ruxolitinib, a Janus kinase (JAK) 1 and 2 inhibitor, was shown to have a clinical benefit in patients with PV. A phase 3 study (RESPONSE) have shown that PV patients on Ruxolitinib at dose of 10 mg twice daily at week 32 had a complete hematologic remission. In this study were enrolled 40 patients with PV (30 men, 10 women; mean age 54 years, range 51-57) according to WHO criteria, assigned to Ruxolitinib at dose of 5 mg twice daily for clinical evidence of liver dysfunction. All patients were evaluated for JAK2V617F allele burden, HCT, white cells and platelets, splenomegaly and symptom burden, including pruritus, fatigue and night sweats. The mean duration of disease was 9 years. All patients received low-dose aspirin and underwent phlebotomy. Before Ruxolitinib, all patients had JAK2V617F allele burden > 50%, HCT control on phlebotomy, high white cells (12x109/L) and elevated platelets (600x109/L) and spleen volume of 450 cm3 or more as measured by magnetic resonance imaging (MRI) or computed tomography (CT). After Ruxolitinib we observed a shortened response time at week 6 marked by JAK2V617F allele burden < 50%, HCT < 45% in the absence of phlebotomy, normal white cells and platelets (6x109/L and 320x109/L, respectively) and reduced spleen size as assessed by palpation and absence of symptoms. These data suggest that the Ruxolitinib treatment at the alternative dose of 5 mg twice daily can be effective in achieving a rapid and complete hematologic remission that is still present in these patients receiving this dose of Ruxolitinib at the time of this analysis. Disclosures No relevant conflicts of interest to declare.

Anti-Glucosylsphingosine Autoimmunity, JAK2V617F-Dependent Interleukin-1β and JAK2V617F-Independent Cytokines in Myeloproliferative Neoplasms

Inflammatory cytokines play a major role in myeloproliferative neoplasms (MPNs) as regulators of the MPN clone and as mediators of clinical symptoms and complications. Firstly, we investigated the effect of JAK2V617F on 42 molecules linked to inflammation. For JAK2V617F-mutated patients, the JAK2V617F allele burden (%JAK2V617F) correlated with the levels of IL-1β, IL-1Rα, IP-10 and leptin in polycythemia vera (PV), and with IL-33 in ET; for all other molecules, no correlation was found. Cytokine production was also studied in the human megakaryocytic cell line UT-7. Wild-type UT-7 cells secreted 27/42 cytokines measured. UT-7 clones expressing 50% or 75% JAK2V617F were generated, in which the production of IL-1β, IP-10 and RANTES was increased; other cytokines were not affected. Secondly, we searched for causes of chronic inflammation in MPNs other than driver mutations. Since antigen-driven selection is increasingly implicated in the pathogenesis of blood malignancies, we investigated whether proinflammatory glucosylsphingosine (GlcSph) may play a role in MPNs. We report that 20% (15/75) of MPN patients presented with anti-GlcSph IgGs, distinguished by elevated levels of 11 cytokines. In summary, only IL-1β and IP-10 were linked to JAK2V617F both in patients and in UT-7 cells; other inflammation-linked cytokines in excess in MPNs were not. For subsets of MPN patients, a possible cause of inflammation may be auto-immunity against glucolipids.

Evaluation of the JAK2V617F mutational burden in patients with philadelphia chromosome negative myeloproliferative neoplasms: A single-center experience

The identification of the JAK2V617F mutation in several distinct myeloproliferative neoplasms (MPNs) raised the question how one single mutation incites expression of at least three different clinical phenotypes, i.e., polycythemia vera (PV), essential thrombocythemia (ET) and primary myelofibrosis (PMF). In order to further evaluate already published data on the correlation between mutant JAK2V617F allele burden and specific hematological and clinical parameters, we tested the level of the JAK2 mutation in 134 JAK2+ patients with different MPNs. The patients were diagnosed according to the 2008 WHO criteria and followed for a median of 48 months. The JAK2 V617F quantification was done with a real time polymerase chain reaction (real time-PCR) method. The median allele burden was lowest in ET (25.8%), followed by 34.6% in PV and 51.8% in PMF patients (p<0.01). There was statistically significant association between the mutational load of 10.0-50.0% and blood count parameters in the PV patients (p<0.05). In PMF patients the mutational load was in correlation with older age and leukocyte count that were higher in patients with the mutational load of 10.0-50.0% and >50.0% compared to those with a mutational load of <10.0%. There were no statistically significant associations between the allele burden and blood counts in the ET cohort. Our study confirmed an association between the JAK2V617F allele burden and the distinct MPN phenotypes, indicating unfavorable prognosis in patients with a higher JAK2 allele burden. Our results suggest that JAK2 quantification should be incorporated in the diagnostic work-up of MPN patients as a useful tool for optimal treatment decision.

Thromboembolic Risk Reduction and High Rate of Complete Molecular Response with Long-Term Use of Ropeginterferon Alpha-2b in Polycythemia Vera: Results from a Randomized Controlled Study

Introduction: The key treatment goals for polycythemia vera (PV) are to prevent thromboembolic events and minimize the risk of progression, ultimately modifying the natural history of the disease by selectively targeting the malignant clone. In the PROUD-PV/CONTINUATION-PV study, long-term treatment with ropeginterferon alpha-2b (BESREMi®; hereafter ropeg) was compared with standard cytoreductive therapy regarding thromboembolic and other adverse events as well as hematological and molecular parameters over a four-year period. Methods: Cytoreduction-naïve or HU-pre-treated patients aged ≥18 years diagnosed with PV according to WHO 2008 criteria were eligible. A total of 257 patients were randomly allocated to ropeg or hydroxyurea at individualized doses for 12 months in the initial study phase (PROUD-PV). In the ongoing extension phase (CONTINUATION-PV), patients in the hydroxyurea arm were permitted to switch to best available treatment. Efficacy assessments included a longitudinal analysis of complete hematological response (CHR) and complete molecular response (CMR; JAK2V617F was determined using real-time PCR [ipsogen® JAK2 MutaQuant® kit; QIAGEN GmbH]), defined by modified ELN criteria. Discontinued patients were considered non-responders. A data snapshot was performed once all patients reached 48 months of treatment; all available safety data were included. Results: Ninety-five patients in the ropeg arm and 76 in the control arm entered the extension phase. At the time of analysis 139 patients remained on study: 74/95 in the ropeg arm and 65/76 in the control arm. Almost all patients in the control arm (&gt;97% at the last available assessment) continued on HU. The rate of patients in CHR was significantly higher in the ropeg arm than in the control arm in the 4th year (60.6% versus 43.4%; p=0.02), as seen after 2 and 3 years of treatment. In line with this effective control of hematologic parameters by ropeg, a very low rate of major thromboembolic adverse events was observed in the ropeg arm: 0.0%, 0.0% and 1.1% of patients in the 2nd, 3rd and 4th years, respectively. In the control arm, rates of major thromboembolic adverse events in the 2nd, 3rd and 4th year were 0.9%, 1.4% and 0.0%, respectively. The median JAK2V617F allele burden declined from 37.3% at baseline to 9.8% over 4 years in the ropeg arm, whereas in the control group, the median allele burden increased from 38.1% to 43.1% in the same period (p&lt;0.0001). The rate of molecular response (partial or complete) at 48 months was significantly higher among ropeg-treated patients than in the control arm (67.0% versus 25.7%; RR: 2.5 [95% CI: 1.7 to 3.7; p&lt;0.0001]). No patients achieved CMR in the control arm. In the ropeg arm, 13 patients had a JAK2V617F allele burden below the threshold of 1% at month 48, 11 of whom also had a CHR at this time point. An additional 34 patients in the ropeg arm achieved an allele burden &lt;10% at 48 months, suggesting that further patients may reach the &lt;1% threshold with ongoing treatment. In terms of safety, no new signals were detected in the 4th year. Rates of patients with treatment-related adverse events remained similar in the ropeg and control arms in the 4th year (ropeg: 28.7% of patients; control: 22.9%). Disease or treatment-related secondary malignancies reported in the entire study period comprised 2 cases of acute leukemia, 2 cases of basal cell carcinoma and 1 case of malignant melanoma, all in the control group; 1 case of disease-related transformation to myelofibrosis occurred in each treatment arm. Conclusions: Ropeg minimizes the occurrence of thromboembolic events in patients with PV over long-term treatment, without leukemogenic risk. In addition, we show for the first time in a randomized study that, in contrast to hydroxyurea, long-term ropeg treatment is capable of inducing deep molecular responses including CMR, which underscores its disease modifying potential. These results also suggest that selected patients could achieve operational cure (with both CHR and CMR) with ropeg, opening the way for treatment discontinuation. Disclosures Kiladjian: Novartis: Honoraria, Research Funding; AOP Orphan: Honoraria, Research Funding; Celgene: Consultancy. Klade:AOP Orphan Pharmaceuticals AG: Employment. Illés:Takeda, Seattle: Research Funding; Janssen, Celgene, Novartis, Takeda, Roche, Pfizer: Honoraria, Membership on an entity's Board of Directors or advisory committees. Mayer:AOP Orphan Pharmaceuticals AG: Research Funding. Krejcy:AOP Orphan Pharmaceuticals AG: Employment. Hasselbalch:Novartis: Research Funding; AOP Orphan Pharmaceuticals: Other: Data monitoring board. Kralovics:Pharma Essentia: Honoraria; MyeloPro Diagnostics and Research: Equity Ownership; AOP Orphan Pharmaceuticals AG: Honoraria, Other: Advisory board; Qiagen: Honoraria; Novartis: Honoraria. Gisslinger:Celgene GmbH: Honoraria; Pharma Essentia: Other: Personal fees; Roche Austria GmbH: Consultancy; Janssen-Cilag: Honoraria; Novartis Pharma GmbH: Consultancy, Honoraria, Research Funding; AOP Orphan Pharmaceuticals: Consultancy, Honoraria, Research Funding; Myelopro GmbH: Consultancy.

Superiority of IFN Versus HU Using a Novel Biomarker-Based Tool for Assessment of Disease Burden in MPNs

Background: Treatment of polycythemia vera (PV) patients with hydroxyurea (HU) normalizes elevated blood cell counts within weeks in the large majority of patients. Studies on the impact of HU upon the kinetics of the JAK2V617F allele burden, leukocyte and platelets over time are scarce, and results have been reported highly heterogeneous. Purpose: Using data driven analysis as a novel tool to model the kinetics of the JAK2V617F allele burden and blood cell counts over time during treatment with HU. Material and Methods: Using serial measurements of JAK2V617F and correlation analyzes of routine hematological values (Hb-concentration, leukocyte count, platelet count, lactic dehydrogenase), we present a detailed description and analysis of the kinetics of the JAK2V617F, leukocyte and platelet counts and lactic dehydrogenase in 29 PV patients who were followed in the Danish randomized trial (DALIAH) comparing the efficacy of pegylated interferon-alpha2 (IFN) versus HU in patients older than 60 years. Results: Response patterns were highly heterogeneous. In the large majority of patients, HU treatment was initially associated with a modest decline in the JAK2V617F allele burden in concert with a decline in leukocyte and platelet counts. However, HU did not induce a sustained and continuous decrease in the JAK2V617F allele burden in any patient as previously reported in patients being treated with IFN. Importantly, HU treatment was neither able to induce a sustained normalization of elevated leukocyte and platelet counts, although counts were temporarily normalized in most patients during the first months of therapy. The fluctuating leukocyte and platelet counts contrast the sustained normalization of cell counts in the large majority of patients during long term treatment with IFN. Discussion and Conclusions: Using data-driven analysis of the JAK2V617F allele burden, leukocyte and platelet kinetics during treatment with HU, we have shown that HU does not induce a sustained decrease in the JAK2V617F allele burden and neither induces sustained normalization of elevated cell counts in PV patients. Our results may explain why PV patients during treatment with HU still have a substantially increased risk of thrombosis. Based upon our previous and present findings, obtained by mathematical modelling and data driven analysis studies, a rational and cost-effective treatment might be a combination therapy of HU and IFN, both being used for decades in the treatment of PV but according to the findings in our studies now being proposed to be combined in the initial treatment period, since their combined effects might be highly efficacious and are foreseen to have the potential to minimize the risk of thrombosis and bleeding. By these studies, we have also proven mathematical modelling and data driven analysis to be highly important tools to decipher novel treatment modalities for patients suffering from MPN cancers but likely other cancers as well. Disclosures Hasselbalch: Novartis: Research Funding; AOP Orphan Pharmaceuticals: Other: Data monitoring board. OffLabel Disclosure: Interferon-alpha2 for the treatment of myeloproliferative neoplasms.