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Background: Most patients with myelofibrosis develop ruxolitinib intolerance or disease that is relapsed or refractory, and survival rates after ruxolitinib discontinuation are poor. We aimed to evaluate the safety and efficacy of fedratinib versus best available therapy (BAT) in patients with myelofibrosis previously treated with ruxolitinib., Methods: FREEDOM2 was a multicentre, open-label, randomised, controlled, phase 3 trial in 86 clinics in 16 countries, in which patients aged at least 18 years with intermediate-2 or high-risk myelofibrosis that was relapsed or refractory or intolerant to ruxolitinib with Eastern Cooperative Oncology Group performance status 0-2 were stratified by spleen size by palpation, platelet count, and previous ruxolitinib treatment, and randomly assigned 2:1 by interactive response technology to receive fedratinib 400 mg per day (4 × 100 mg capsules orally once daily, open-label) or BAT. Patients received prophylactic antiemetics and thiamine supplementation, and symptomatic antidiarrhoeals as required. Primary endpoint was proportion of patients reaching spleen volume reduction (SVR) of at least 35% (SVR35) at end of cycle 6 in the intention-to-treat population. This manuscript reports the primary analysis of the trial; follow-up is ongoing. This trial is registered at clinicaltrials.gov, NCT03952039., Findings: Between Sept 9, 2019 and June 24, 2022, of 316 patients screened, 201 were randomly assigned and treated (134 to fedratinib, 67 to BAT [including 52 receiving ruxolitinib]); 46 patients from the BAT group crossed over to fedratinib. Approximately half of enrolled patients were male (fedratinib 75 [56%] of 134; BAT 30 [45%] of 67) and most were White (fedratinib 106 [79%] of 134; BAT 58 [87%] of 67). At data cutoff (Dec 27, 2022), median survival follow-up was 64·5 weeks (IQR 37·9-104·9). SVR35 at end of cycle 6 was seen in 48 (36%) of 134 patients receiving fedratinib versus four (6%) of 67 patients receiving BAT (30% difference; 95% CI 20-39; one-sided p-value <0·0001). During the first six cycles 53 (40%) of 134 patients in the fedratinib group and 8 (12%) of 67 patients in the BAT group had grade 3 or greater treatment-related adverse events, most frequently anaemia (fedratinib 12 [9%] of 134; BAT 6 [9%] of 67) and thrombocytopenia (fedratinib 16 [12%] of 134; BAT 2 [3%] of 67); one patient in the fedratinib group died from acute kidney injury suspected to be related to study drug (no treatment-related deaths in the BAT group). Gastrointestinal adverse events occurred more frequently in the fedratinib group compared with the BAT group, but were mostly grade 1-2 in severity and more frequent in early cycles, and were less frequent than in prior clinical trials. A total of 28 (21%) of 134 patients in the fedratinib group and 3 (4%) of 67 patients in the BAT group had thiamine levels below lower limit of normal per central laboratory assessment, with only one case of low thiamine in the fedratinib arm after the introduction of prophylactic thiamine supplementation., Interpretation: Findings from FREEDOM2 support fedratinib as a second-line Janus kinase inhibitor option to reduce spleen size after ruxolitinib failure or intolerance in patients with myelofibrosis, and shows effective strategies for management of gastrointestinal adverse events and low thiamine concentrations through prophylaxis, monitoring, and treatment., Funding: Bristol Myers Squibb., Competing Interests: Declaration of interests CNH reports research funding from Bristol Myers Squibb, Constellation–Morphosys, and Novartis; consulting fees from Galecto, Geron, and GlaxoSmithKline; honoraria from AbbVie, AOP Health, Bristol Myers Squibb–Celgene, CTI BioPharma, Galacteo, Geron, Gilead, IMAGO, Janssen, Keros, Novartis, Promedior, Roche, Shire, and Sierra; participation on a data safety monitoring board or advisory board with Galacteo and Keros; and leadership at the European Hematology Association. RM reports honoraria from AbbVie, Blueprint, Bristol Myers Squibb, CTI BioPharma, Genentech, Geron, GlaxoSmithKline, Incyte, Morphosys, Novartis, Sierra Oncology, and Telios. MT reports research funding from Bristol Myers Squibb; travel support from Sumitomo; participation on a data safety monitoring board or advisory board with Bristol Myers Squibb, Novartis, and Sumitomo; and leadership in the Society of Hematologic Oncology. HKA-A reports research funding from Bristol Myers Squibb, Incyte, and Novartis; travel support from AbbVie and Bristol Myers Squibb; and participation on a data safety monitoring board or advisory board with AbbVie, AOP Health, Blueprint, Bristol Myers Squibb, Novartis, and SGK. FPas reports research funding from Bristol Myers Squibb–Celgene; consulting fees from AbbVie, AOP Health, Bristol Myers Squibb–Celgene, Kartos, Karyopharma, Kyowa Kirin–MEI, Novartis, Roche, Sierra Oncology, and Sumitomo; and honoraria from AbbVie, AOP Health, Bristol Myers Squibb–Celgene, Novartis, and Roche. FPal reports research funding from Bristol Myers Squibb; honoraria from AbbVie, Amgen, AOP Health, Bristol Myers Squibb, CTI BioPharma, GlaxoSmithKline, Kartos, Novartis, and Telios; travel support from AbbVie and Novartis; and participation on a data safety monitoring board or advisory board with AbbVie, AOP Health, Bristol Myers Squibb, CTI BioPharma, GlaxoSmithKline, and Novartis. GB reports honoraria and participation on a data safety monitoring board or advisory board with Bristol Myers Squibb, Janssen, and Novartis. AMV reports honoraria from AbbVie, Bristol Myers Squibb, Geron, GlaxoSmithKline, Incyte, and Novartis; and participation on a data safety monitoring board or advisory board with Bristol Myers Squibb, Geron, Incyte, and Novartis. CM reports research funding from AbbVie and Bristol Myers Squibb; and honoraria from AbbVie, Bristol Myers Squibb, and Novartis. AI reports honoraria from Bristol Myers Squibb, GlaxoSmithKline, Incyte, Novartis, and Pfizer; and participation on a data safety monitoring board or advisory board with AOP Health, Bristol Myers Squibb, Incyte, Novartis, and Pfizer. PB reports employment and stock or stock options with Bristol Myers Squibb. CH reports employment with Bristol Myers Squibb. SR reports employment and stock or stock options with Bristol Myers Squibb. JW reports employment with Bristol Myers Squibb. J-JK reports consulting fees from AbbVie and GlaxoSmithKline; honoraria from AOP Health and Novartis; and participation on a data safety monitoring board or advisory board with Bristol Myers Squibb and Incyte. BX and IK report no competing interests., (Copyright © 2024 Elsevier Ltd. All rights reserved, including those for text and data mining, AI training, and similar technologies.)

Background: The MOMENTUM study met all key endpoints at week 24, demonstrating symptom, spleen, and anaemia benefits with momelotinib versus danazol in patients with myelofibrosis. In this updated analysis, we report duration of week 24 responses and new responses with momelotinib through week 48., Methods: MOMENTUM is an international, double-blind, randomised, phase 3 study done at 107 sites across 21 countries. Patients were 18 years or older with primary, post-polycythaemia vera, or post-essential thrombocythaemia myelofibrosis, previously treated with an approved Janus kinase (JAK) inhibitor for 90 days or more (≥28 days with haematological complications), and had an Eastern Cooperative Oncology Group performance status of 2 or less. Patients were randomly assigned (2:1) to either the momelotinib group (200 mg orally once per day) or danazol group (300 mg orally twice per day) through week 24 via non-deterministic biased coin minimisation and an interactive response system. Stratification factors were Total Symptom Score (TSS; <22 vs ≥22), spleen size (<12 cm vs ≥12 cm), transfusion burden (0 units vs 1-4 units vs ≥5 units), and study site. After week 24, all patients initially randomly assigned to either group who remained on the study received open-label momelotinib. The primary endpoint, which has already been reported, was Myelofibrosis Symptom Assessment Form TSS response rate at week 24. Predefined secondary endpoints were duration of week 24 TSS and transfusion independence responses, safety, and survival, which are summarised post hoc at the week 48 data cutoff (May 17, 2022). TSS, transfusion independence, and splenic responses at week 48 were defined post hoc and assessed in all evaluable patients who entered the open-label period and provided sufficient data. The timing of this updated analysis was defined post hoc after all patients had the opportunity to complete their week 48 assessments, as most patients entered an extended access study (NCT03441113) after week 48. This study is registered with ClinicalTrials.gov, number NCT04173494, and is now complete., Findings: Between April 24, 2020, and Dec 3, 2021, a total of 195 patients were randomised (130 [67%] in the momelotinib group and 65 [33%] in the danazol group). 93 (72%) of 130 patients in the momelotinib group and 41 (63%) of 65 in the danazol group entered the momelotinib open-label extension period. Median follow-up was 48·4 weeks (IQR 40·6-55·7). Among TSS-evaluable patients at week 48, 30 (45%) of 67 patients in the momelotinib group who continued treatment and 15 (50%) of 30 in the danazol group who crossed over were responders. TSS responders at any time during the open-label period by week 48 were 46 (61%) of 75 evaluable patients in the momelotinib group who continued and 19 (59%) of 32 in the danazol group who crossed over, including most week 24 responders plus new responders after week 24. No new safety signals emerged with long-term follow-up. The most common non-haematological treatment-emergent adverse events in momelotinib-treated patients over the entire study period as of the data cutoff were diarrhoea (45 [26%] of 171) and asthenia (28 [16%]); the most common grades 3-4 treatment-emergent adverse events were thrombocytopenia (33 [19%]) and anaemia (19 [11%]). Serious treatment-emergent adverse events were reported in 79 (46%) of 171 patients, and fatal treatment-emergent adverse events were reported in 30 (18%); two fatal treatment-emergent adverse events were considered possibly related to momelotinib (rotaviral enteritis and Staphylococcus pneumonia)., Interpretation: Momelotinib was associated with durable symptom, spleen, and anaemia benefits, late responses after week 24, and favourable safety through week 48. These results highlight the potential benefits of treatment with momelotinib in patients with myelofibrosis, particularly those with anaemia., Funding: Sierra Oncology, a GSK company., Competing Interests: Declaration of interests ATG reports consulting fees from AbbVie, Bristol Myers Squibb, Constellation/MorphoSys, CTI Biopharma, Imago Biosciences/Merck, Incyte, Pharma Essentia, Sierra Oncology/GSK, and Telios. SV reports consulting fees from GSK. AMV reports payment or honoraria from AbbVie, AOP Health, Bristol Myers Squibb, GSK, Incyte, Novartis, and Roche. HKA-A reports research grants from Bristol Myers Squibb and Incyte; honoraria from AbbVie, Bristol Myers Squibb, GSK, and Novartis; and advisory board participation with AbbVie, Bristol Myers Squibb, GSK, and Novartis. DL reports consulting fees from AbbVie, Medisson, and Takeda; payment or honoraria from AbbVie, Novartis, Roche, and Takeda; travel support from AbbVie; and advisory board participation with AbbVie and Medisson. ATK reports consulting fees from CTI Biopharma, GSK, and Imago Biosciences; payment or honoraria from Bristol Myers Squibb, Incyte, and MorphoSys; travel support from AbbVie and MorphoSys; and advisory board participation with Incyte. AI reports payment or honoraria from Bristol Myers Squibb, GSK, Incyte, Novartis, and Pfizer; and advisory board participation with AOP Health, Incyte, and Novartis. YTG reports consulting fees from AstraZeneca, GSK, Novartis, and Pfizer; and payment or honoraria from AbbVie. MLF reports consulting fees from AbbVie, GSK, Novartis, and Sierra Oncology; payment or honoraria from Bristol Myers Squibb and Novartis; and travel support from AbbVie. DM reports a research grant from Imago Biosciences; payment or honoraria from AbbVie, Bristol Myers Squibb, Jazz Pharma, and Novartis; participation on a data safety monitoring board for the UK ALL-RIC trial; and a leadership or fiduciary role as a member of the EBMT Scientific Council and chair of the EBMT Chronic Malignancies Working Party. S-SY reports grants or contracts from Roche-Genentech, Kyowa Hakko Kirin, and Yuhan Pharma; payment or honoraria from Celgene, Janssen, and Novartis; and advisory board participation with Amgen, Antengene, and Takeda. VG reports consulting fees from AbbVie, Bristol Myers Squibb/Celgene, Constellation Biopharma, CTI Biopharma, GSK, Novartis, Pfizer, and Sierra Oncology; payment or honoraria from Bristol Myers Squibb/Celgene and Novartis; and advisory board participation with AbbVie, Bristol Myers Squibb/Celgene, CTI Biopharma, Pfizer, Roche, and Sierra Oncology. J-JK reports advisory board participation with AbbVie, AOP Health, Bristol Myers Squibb, GSK, Incyte, and Novartis. FP reports grants or contracts from Bristol Myers Squibb; consulting fees from AbbVie, AOP Orphan, Bristol Myers Squibb/Celgene, Kartos, Karyopharm, Kyowa Kirin and MEI, Novartis, Roche, Sierra Oncology, and Sumimoto; and payment or honoraria from AbbVie, AOP Orphan, Bristol Myers Squibb/Celgene, Novartis, and Roche. CNH reports payment for study conduct and advisory board participation, related to the present manuscript; consulting fees from DISC, Galecto, and Keros; payment or honoraria from Bristol Myers Squibb, CTI Biopharma, GSK, Novartis, and Sierra Oncology; advisory board participation with AOP, Keros, Sumimoto, and Telios; and a leadership or fiduciary role with EHA, HemaSphere, and MPN Voice. SO reports consulting fees from AbbVie, Bristol Myers Squibb, Cogent, Constellation, CTI Biopharma, Geron, Incyte, Protagonist, and Sierra Oncology. BJK and RD employment and stock/stock options with Sierra Oncology, a GSK company. JY reports employment and stock or stock options with GSK. JK reports employment and stock or stock options with Sierra Oncology, a GSK company; and stock or stock options with Gilead. RM reports consulting fees from AbbVie, Blueprint, Bristol Myers Squibb, CTI, Genentech, Geron, GSK, Incyte, MorphoSys, Novartis, Sierra Oncology, and Telios. All authors received medical writing support related to the present manuscript, funded by GSK. SG, MCL, ME, NG, AP, S-EL, and LO declare no other competing interests., (Copyright © 2023 Elsevier Ltd. All rights reserved.)

Background: In the PEGASUS trial, the complement C3 inhibitor, pegcetacoplan, showed superiority to eculizumab in improving haematological outcomes in adult patients with paroxysmal nocturnal haemoglobinuria and suboptimal response to eculizumab at 16 weeks. The aim of the open-label period was to evaluate the long-term efficacy and safety of pegcetacoplan through to 48 weeks., Methods: PEGASUS was a phase 3, randomised, open-label, active-comparator controlled trial conducted in 44 centres in Australia, Belgium, Canada, France, Germany, Japan, Russia, South Korea, Spain, the UK, and the USA. Eligible participants were aged 18 years or older, had paroxysmal nocturnal haemoglobinuria, and had a haemoglobin concentration of less than 10·50 g/dL after 3 months or longer of stable eculizumab treatment. After a 4-week run-in with eculizumab plus pegcetacoplan, patients were randomly assigned (1:1) by interactive response technology to pegcetacoplan (1080 mg subcutaneously twice weekly) or eculizumab (according to their regimen at enrolment) for 16 weeks and could continue to the open-label period (32 weeks of pegcetacoplan monotherapy [pegcetacoplan-to-pegcetacoplan] or 28 weeks of pegcetacoplan monotherapy [eculizumab-to-pegcetacoplan]). Randomisation was stratified by platelet count and number of previous blood transfusions. The primary endpoint was change from baseline in haemoglobin at week 16, which has previously been reported. The outcomes of the open-label period (week 16 to week 48) are reported here. At 48 weeks, efficacy (including mean haemoglobin concentration and quality of life measured on the Functional Assessment of Chronic Illness Therapy [FACIT]-Fatigue scale) was assessed in the intention-to-treat population and safety was assessed per protocol. This trial was registered with ClinicalTrials.gov, NCT03500549, and has been completed., Findings: Between June 14, 2018, and Nov 14, 2019, 80 patients were randomly assigned to receive treatment with pegcetacoplan (41 patients) or eculizumab (39 patients). Most participants were women (49 [61%]) and 31 (39%) were men; 12 (15%) were Asian, two (3%) were Black, 49 (61%) were White, and 17 (21%) were another race or did not report their race. The open-label period had 77 participants (38 pegcetacoplan-to-pegcetacoplan, 39 eculizumab-to-pegcetacoplan). Patients in the pegcetacoplan-to-pegcetacoplan group maintained high mean haemoglobin concentrations between 16 weeks (11·54 g/dL [SD 1·96]) and 48 weeks (11·30 g/dL [1·77]; p=0·14). Patients in the eculizumab-to-pegcetacoplan group had significantly greater mean haemoglobin concentrations at 48 weeks (11·57 g/dL [2·21]) versus 16 weeks (8·58 g/dL [0·96]; p<0·0001). Clinically meaningful improvements in FACIT-Fatigue scores were observed at 48 weeks, with a mean change from baseline for all patients receiving pegcetacoplan monotherapy of 9·89 points (SD 9·63), for patients in the pegcetacoplan-to-pegcetacoplan group mean 10·14 points (9·06), and for patients in the eculizumab-to-pegcetacoplan group mean 9·62 points (10·34). During the entire study period, 13 (16%) of 80 patients discontinued treatment (three [7%] of 41 through to week 16 due to breakthrough haemolysis, and ten [13%] of 77 due to severe treatment-emergent adverse events) and 18 patients (eight pegcetacoplan-to-pegcetacoplan, ten eculizumab-to-pegcetacoplan) had at least one serious treatment-emergent adverse event during the open-label period, four were considered to be related to pegcetacoplan treatment. The most common treatment-emergent adverse events (in ≥10% patients) among both pegcetacoplan-treated groups during the open-label period were injection site reactions (in 20 [26%] of 77 patients), haemolysis (15 [19%]), nasopharyngitis (12 [16%]), and diarrhoea (ten [13%]). No treatment-related deaths occurred throughout the duration of the study., Interpretation: The durability of improved haematological outcomes and favourable safety profile over 48 weeks of treatment suggests that pegcetacoplan has the potential to improve treatment benefit and alter treatment goals in patients with paroxysmal nocturnal haemoglobinuria., Funding: Apellis Pharmaceuticals., Competing Interests: Declaration of interests RPdL reports consultancy at Novartis, Pfizer, Amgen, Alexion Pharmaceuticals, Apellis Pharmaceuticals, and Swedish Orphan Biovitrum; honoraria from Novartis, Pfizer, Amgen, Alexion Pharmaceuticals, Apellis Pharmaceuticals, and Swedish Orphan Biovitrum; research funding from Novartis, Pfizer, Amgen, and Alexion Pharmaceuticals; and grants from Alexion Pharmaceuticals, Amgen, Novartis, and Pfizer. JS reports consultancy at Novartis, Alexion Pharmaceuticals, and Apellis Pharmaceuticals; honoraria from Takeda, Pfizer, Novartis, Prevail Therapeutics, and Alexion Pharmaceuticals; speakers’ bureau at Takeda, Pfizer, Novartis, and Alexion Pharmaceuticals; and membership on an entity's board of directors or advisory committees at Prevail Therapeutics and Alexion Pharmaceuticals. ICW reports consultancy at Alexion Pharmaceuticals, Apellis Pharmaceuticals, Biocryst, Novartis, and Sanofi Genxyme; honoraria from Alexion Pharmaceuticals, Apellis Pharmaceuticals, Biocryst, Novartis, and Sanofi Genxyme; and speakers’ bureau at Alexion Pharmaceuticals. AR reports personal fees from Alexion Pharmaceuticals, Apellis Pharmaceuticals, Kira, Novartis, Roche, Swedish Orphan Biovitrum, Sanofi, Bioverativ, and Grifols; and grants from Roche. BH reports honoraria and advisory board member at Novartis, Roche, Alexion Pharmaceuticals, and Apellis Pharmaceuticals. JP reports consultancy and honoraria at Blueprint Medicines, Amgen, F Hoffmann-La Roche, MSD, Bristol Myers Squibb, Alexion Pharmaceuticals, Novartis, Pfizer, Gilead, Boehringer Ingelheim, Swedish Orphan Biovitrum, and Apellis Pharmaceuticals; and honoraria from SwixxBiopharma. KU reports grants from Alexion Pharmaceuticals, Apellis Pharmaceuticals, Chugai, and Novartis; and personal fees from Novartis, Chugai, and Alexion Pharmaceuticals. MG reports consultancy at Biocryst and Regeneron Pharmaceuticals; honoraria from Alexion Pharmaceuticals and Swedish Orphan Biovitrum; advisory board member at Novartis, Biocryst, Alexion Pharmaceuticals, and Swedish Orphan Biovitrum; and educational work sponsored by Apellis with unrestricted grant paid to Medscape. J-JK reports membership on an entity's board of directors or advisory committees at AbbVie, Novartis, Bristol Myers Squibb, and AOP Orphan. CMdC reports consultancy at Apellis Pharmaceuticals; honoraria from Novartis, Alexion Pharmaceuticals, Biocryst, and Apellis Pharmaceuticals; and research funding from Alexion Pharmaceuticals, and Apellis Pharmaceuticals. TA reports current employment and current equity holder at Apellis Pharmaceuticals. MA-A reports current employment at Apellis Pharmaceuticals. PD reports being a founder, Chief Scientific Officer, and current equity holder at Apellis Pharmaceuticals. CF and FG report current employment and current equity holder at Apellis Pharmaceuticals. AMR reports consultancy at Novartis and Amyndas; membership on an entity's board of directors or advisory committees at Novartis, Alexion Pharmaceuticals, Samsung, Biocryst, Achillion, Roche, Sanofi, and Apellis Pharmaceuticals; and grants from Alexion Pharmaceuticals, Novartis, Alnylam, and Rapharma. PH reports consultancy at Alexion Pharmaceuticals, Apellis Pharmaceuticals, AbbVie, AstraZeneca, Janssen, and Roche; research funding from Alexion Pharmaceuticals, Apellis Pharmaceuticals, AbbVie, Gilead, Janssen, Pharmacyclics, and Roche; and speakers bureau at Alexion Pharmaceuticals, Apellis Pharmaceuticals, AbbVie, AstraZeneca, Janssen, and Roche. HN declares no competing interests., (Copyright © 2022 Elsevier Ltd. All rights reserved.)

Polycythaemia vera is associated with a reduced quality of life, a high rate of vascular events, and an intrinsic risk of disease evolution. The results of several randomised trials for the treatment of this disorder are now available, and both a new ropegylated formulation of interferon alfa-2b (ropeginterferon alfa-2b; 2018) and ruxolitinib (2015) have been approved in Europe. European LeukemiaNet (ELN) investigators have therefore deemed it appropriate to provide recommendations for the use of these drugs in clinical practice. An expert panel of 14 senior haematologists from ELN centres that had actively participated in previous ELN projects or relevant randomised trials, chaired by a member of the ELN Steering Committee, developed a list of clinical questions, and a methodologist established three patient, intervention, comparator, outcome (PICO) questions and systematically reviewed the evidence. Recommendations were approved by six Delphi consensus rounds and two virtual meetings (on Jan 26, 2021, and June 24, 2021). The expert panel recommended that patients with polycythaemia vera who are younger than 60 years and have not had previous thrombotic events should start cytoreductive drug therapy if at least one of the following criteria are fulfilled: strictly defined intolerance to phlebotomy, symptomatic progressive splenomegaly, persistent leukocytosis (>15 × 10 9 white blood cells per L), progressive leukocytosis (at least 100% increase if baseline count is <10 × 10 9 cells per L or at least 50% increase if baseline count is >10 × 10 9 cells per L), extreme thrombocytosis (>1500 × 10 9 platelets per L), inadequate haematocrit control requiring phlebotomies, persistently high cardiovascular risk, and persistently high symptom burden. Recombinant interferon alfa, either in the form of ropeginterferon alfa-2b or pegylated interferon alfa-2a, is the recommended cytoreductive treatment for these patients. The expert panel suggested that either interferon alfa or ruxolitinib should be considered for patients who are being treated with hydroxyurea but require a therapy change., Competing Interests: Declaration of interests MM has received consulting fees from Gilead Sciences, speaker fees from Amgen, support for attending meetings from Takeda, and is a member of the guideline committee of the Italian Society of Hematology. AMV has received speaker fees from Novartis, AOP Health, Incyte, AbbVie, GlaxoSmithKline (GSK), and Bristol Myers Squibb (BMS); and has participated on the advisory boards of Novartis, Incyte, AOP Orphan Pharmaceuticals, AbbVie, GSK, BMS, and Roche. MG has received consulting and speaker fees, support for attending meetings, and participated on advisory boards for AOP Health, Novartis, Celgene, Amgen, AstraZeneca, CTI BioPharma, Shire, Pfizer, Roche, Janssen Pharmaceuticals, and Gilead Sciences. CH has received grants or contracts with payment to her institution from Novartis, Celgene, and Constellation Pharmaceuticals; consulting fees from Keros Therapeutics, Galecto Biotech, and Roche; speaker fees from Novartis, Celgene, CTI BioPharma, AbbVie, Gilead Sciences, Janssen Pharmaceuticals, Promedior, and Geron Corporation; support for attending meetings from Novartis and Celgene, and has participated on advisory boards for Roche, CTI Biopharma, Geron Corporation, Promedior, AbbVie, AOP Orphan Pharmaceuticals, and Galecto. SK has received research grants from AOP Health, Novartis, Janssen Pharmaceuticals, and Imago BioScience; consulting fees from Pfizer, CTI BioPharma, Sanofi, Novartis, BMS/Celgene, Incyte/ARIAD, Roche, AOP Orphan Pharmaceuticals, and Janssen Pharmaceuticals; speaker fees from Pfizer, CTI BioPharma, Sanofi, Novartis, BMS/Celgene, Incyte/ARIAD, Roche, AOP Orphan Pharmaceuticals, Janssen Pharmaceuticals, Kartos Therapeutics, and Imago BioScience; support for attending meetings from Alexion Pharmaceuticals, Novartis, BMS/Celgene, Incyte/ARIAD, AOP Orphan Pharmaceuticals, CTI BioPharma, Pfizer, Sanofi, Janssen Pharmaceuticals, Geron Corporation, Kartos Therapeutics, Sierra Oncology, Imago BioScience; has participated on advisory boards for Pfizer, CTI BioPharma, Sanofi, Novartis, BMS/Celgene, Incyte/ARIAD, Roche, AOP Orphan Pharmaceuticals, Kartos Therapeutics, and Imago BioScience; has patents planned, issued, or pending from Rheinisch-Westfalische Technische Hochschule Aachen; and has a leadership role in Deutsche Gesellschaft fur Hamatologie und Medizinische Onkologie. HG has received research grants and support for attending meetings from AOP Orphan Pharmaceuticals and Novartis; consulting fees from AOP Orphan Pharmaceuticals, Novartis, and BMS/Celgene; and speaker fees from AOP Orphan Pharmaceuticals, Novartis, BMS/Celgene, and Janssen. AÁ-L has participated on advisory boards and has received speaker fees from Novartis, AOP Orphan Pharmaceuticals, and Celgene; and has received support for attending meetings from Novartis and Pfizer. VDS has received speaker fees from AbbVie and Novartis, and participated on advisory boards of AOP Health and Novartis. PG has received speaker fees from AbbVie and Novartis, and support for attending meetings from Sanofi. FPal has received speaker fees from Novartis and Incyte; consulting fees from AOP Health, CTI BioPharma, Novartis, and Celgene/BMS; and support for attending meetings from Celgene/BMS. FPas has received consulting fees from AbbVie, Novartis, BMS, and Amomed Pharma; and speaker fees from AbbVie, Janssen Pharmaceuticals, Novartis, and BMS. RTS has received research grants from the Cancer Research & Treatment Fund and Johns Family Fund, received speaker fees and payment for expert testimony from PharmaEssentia, participated on an advisory board for PharmaEssentia, and has a leadership role (Vice-President and Medical Director) at the Cancer Research & Treatment Fund. J-JK received consulting fees from AbbVie and Novartis; speaker fees from AOP Orphan Pharmaceuticals, Novartis, and BMS; and has participated on advisory boards for Incyte. TB has received research grants and speaker fees from AOP Orphan Pharmaceuticals and Novartis, and consultancy fees from AOP Orphan Pharmaceuticals. GB and RH declare no competing interests., (Copyright © 2022 Elsevier Ltd. All rights reserved.)

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 9 platelets per L, in such cases cytoreduction is an adequate option, especially if adquired Von Willebrand disease is present; cytoreduction is recommended for extreme thrombocytosis (platelet count >1500 × 10 9 platelets per L) with pegylated interferon alfa being the preferred option for younger patients; both hydroxycarbamide and anagrelide might be given to patients ineligible for pegylated interferon alfa; and treatment algorithms for patients with high-risk pregnancies should not be changed according to genotype. The European LeukemiaNet proposes to use these recommendations in the routine management of patients with CALR-mutated essential thrombocythaemia, and designing new clinical studies in this field might be useful., Competing Interests: Declaration of interests AA-L participated in data safety monitoring boards and advisory boards and has received speaker and consulting fees from Novartis, AOP Orphan, and Celgene. CH had grants or contracts with payment to her institution from Novartis, Celgene, and Constellation, consulting fees from Keros, Galecto, and Roche, speaker fees from Novartis, Celgene, CTI BioPharma, Gilead, Jannsen, Promedior, and Geron, and participated on a data safety monitoring board and advisory board for Roche and Galecto. ER received speaker fees from Novartis and participated in the Abbvie advisory board. FP received speaker fees from Novartis, AOP, and Celgene. JCI received speaker fees from Novartis. J-JK received consulting fees from Abbvie and Novartis, speaker fees from AOP Orphan, Novartis, and Bristol Myers Squibb (BMS), and participated in advisory boards for Incyte. JN received grants from MPN Research Foundation, Alborada Trust, and Rosetrees Trust, and speaker fees from Jazz Pharmaceutical. MG received consulting and speaker fees, payment for expert testimony, support for attending meetings, and participated in data safety monitoring board and advisory board from AOP, Novartis, Celgene, BMS, Amgen, and AstraZeneca. RM received grants from Celgene, Incyte, Abbvie, Samus, Genotech, Promedior, and CTI BioPharma, consulting fees from Novartis, Sierra Onc, LaJolla, and Pharma. SK received grants from AOP, Janssen, and Novartis, consulting fees from Pfizer, CTI BioPharma, Baxalta, Sanofi, Novartis, BMS–Celgene, Incyte, Shire, Roche, AOP, and Janssen, speaker fees from Pfizer, CTI, Baxalta, Sanofi, Novartis, BMS–Celgene, Incyte, Shire, Roche, AOP, and Janssen, support from attending meetings from Pfizer, CTI BioPharma, Baxalta, Sanofi, Novartis, BMS–Celgene, Incyte, Shire, AOP, Janssen, Alexion, and Geron, patents planned, issued, or pending from Rheinisch-Westfälische Technische Hochschule Aachen, and leadership role in Deutsche Gesellschaft für Hämatologie und Medizinische Onkologie. All other authors have no competing interests., (Copyright © 2021 Elsevier Ltd. All rights reserved.)

Background: The PROUD-PV and CONTINUATION-PV trials aimed to compare the novel monopegylated interferon ropeginterferon alfa-2b with hydroxyurea, the standard therapy for patients with polycythaemia vera, over 3 years of treatment., Methods: PROUD-PV and its extension study, CONTINUATION-PV, were phase 3, randomised, controlled, open-label, trials done in 48 clinics in Europe. Patients were eligible if 18 years or older with early stage polycythaemia vera (no history of cytoreductive treatment or less than 3 years of previous hydroxyurea treatment) diagnosed by WHO's 2008 criteria. Patients were randomly assigned 1:1 to ropeginterferon alfa-2b (subcutaneously every 2 weeks, starting at 100 μg) or hydroxyurea (orally starting at 500 mg/day). After 1 year, patients could opt to enter the extension part of the trial, CONTINUATION-PV. The primary endpoint in PROUD-PV was non-inferiority of ropeginterferon alfa-2b versus hydroxyurea regarding complete haematological response with normal spleen size (longitudinal diameter of ≤12 cm for women and ≤13 cm for men) at 12 months; in CONTINUATION-PV, the coprimary endpoints were complete haematological response with normalisation of spleen size and with improved disease burden (ie, splenomegaly, microvascular disturbances, pruritus, and headache). We present the final results of PROUD-PV and an interim analysis at 36 months of the CONTINUATION-PV study (per statistical analysis plan). Analyses for safety and efficacy were per-protocol. The trials were registered on EudraCT, 2012-005259-18 (PROUD-PV) and 2014-001357-17 (CONTINUATION-PV, which is ongoing)., Findings: Patients were recruited from Sept 17, 2013 to March 13, 2015 with 306 enrolled. 257 patients were randomly assigned, 127 were treated in each group (three patients withdrew consent in the hydroxyurea group), and 171 rolled over to the CONTINUATION-PV trial. Median follow-up was 182·1 weeks (IQR 166·3-201·7) in the ropeginterferon alfa-2b and 164·5 weeks (144·4-169·3) in the standard therapy group. In PROUD-PV, 26 (21%) of 122 patients in the ropeginterferon alfa-2b group and 34 (28%) of 123 patients in the standard therapy group met the composite primary endpoint of complete haematological response with normal spleen size. In CONTINUATION-PV, complete haematological response with improved disease burden was met in 50 (53%) of 95 patients in the ropeginterferon alfa-2b group versus 28 (38%) of 74 patients in the hydroxyurea group, p=0·044 at 36 months. Complete haematological response without the spleen criterion in the ropeginterferon alfa-2b group versus standard therapy group were: 53 (43%) of 123 patients versus 57 (46%) of 125 patients, p=0·63 at 12 months (PROUD-PV), and 67 (71%) of 95 patients versus 38 (51%) of 74 patients, p=0·012 at 36 months (CONTINUATION-PV). The most frequently reported grade 3 and grade 4 treatment-related adverse events were increased γ-glutamyltransferase (seven [6%] of 127 patients) and increased alanine aminotransferase (four [3%] of 127 patients) in the ropeginterferon alfa-2b group, and leucopenia (six [5%] of 127 patients) and thrombocytopenia (five [4%] of 127 patients) in the standard therapy group. Treatment-related serious adverse events occurred in three (2%) of 127 patients in the ropeginterferon alfa-2b group and five (4%) of 127 patients in the hydroxyurea group. One treatment-related death was reported in the standard therapy group (acute leukaemia)., Interpretation: In patients with early polycythaemia vera, who predominantly presented without splenomegaly, ropeginterferon alfa-2b was effective in inducing haematological responses; non-inferiority to hydroxyurea regarding haematological response and normal spleen size was not shown at 12 months. However, response to ropeginterferon alfa-2b continued to increase over time with improved responses compared with hydroxyurea at 36 months. Considering the high and durable haematological and molecular responses and its good tolerability, ropeginterferon alfa-2b offers a valuable and safe long-term treatment option with features distinct from hydroxyurea., Funding: AOP Orphan Pharmaceuticals AG., (Copyright © 2020 Elsevier Ltd. All rights reserved.)

Background: Polycythaemia vera is a myeloproliferative neoplasm characterised by excessive proliferation of erythroid, myeloid, and megakaryocytic components in the bone marrow due to mutations in the Janus kinase 2 (JAK2) gene. Ruxolitinib, a JAK 1 and JAK 2 inhibitor, showed superiority over best available therapy in a phase 2 study in patients with polycythaemia vera who were resistant to or intolerant of hydroxyurea. We aimed to compare the long-term safety and efficacy of ruxolitinib with best available therapy in patients with polycythaemia vera who were resistant to or intolerant of hydroxyurea., Methods: We report the 5-year results for a randomised, open-label, phase 3 study (RESPONSE) that enrolled patients at 109 sites across North America, South America, Europe, and the Asia-Pacific region. Patients (18 years or older) with polycythaemia vera who were resistant to or intolerant of hydroxyurea were randomly assigned 1:1 to receive either ruxolitinib or best available therapy. Patients randomly assigned to the ruxolitinib group received the drug orally at a starting dose of 10 mg twice a day. Single-agent best available therapy comprised hydroxyurea, interferon or pegylated interferon, pipobroman, anagrelide, approved immunomodulators, or observation without pharmacological treatment. The primary endpoint, composite response (patients who achieved both haematocrit control without phlebotomy and 35% or more reduction from baseline in spleen volume) at 32 weeeks was previously reported. Patients receiving best available therapy could cross over to ruxolitinib after week 32. We assessed the durability of primary composite response, complete haematological remission, overall clinicohaematological response, overall survival, patient-reported outcomes, and safety after 5-years of follow-up. This study is registered with ClinicalTrials.gov, NCT01243944., Findings: We enrolled patients between Oct 27, 2010, and Feb 13, 2013, and the study concluded on Feb 9, 2018. Of 342 individuals screened for eligibility, 222 patients were randomly assigned to receive ruxolitinib (n=110, 50%) or best available therapy (n=112, 50%). The median time since polycythaemia vera diagnosis was 8·2 years (IQR 3·9-12·3) in the ruxolitinib group and 9·3 years (4·9-13·8) in the best available therapy group. 98 (88%) of 112 patients initially randomly assigned to best available therapy crossed over to receive ruxolitinib and no patient remained on best available therapy after 80 weeks of study. Among 25 primary responders in the ruxolitinib group, six had progressed at the time of final analysis. At 5 years, the probability of maintaining primary composite response was 74% (95% CI 51-88). The probability of maintaining complete haematological remission was 55% (95% CI 32-73) and the probability of maintaining overall clinicohaematological responses was 67% (54-77). In the intention-to-treat analysis not accounting for crossover, the probability of survival at 5 years was 91·9% (84·4-95·9) with ruxolitinib therapy and 91·0% (82·8-95·4) with best available therapy. Anaemia was the most common adverse event in patients receiving ruxolitinib (rates per 100 patient-years of exposure were 8·9 for ruxolitinib and 8·8 for the crossover population), though most anaemia events were mild to moderate in severity (grade 1 or 2 anaemia rates per 100 patient-years of exposure were 8·0 for ruxolitinib and 8·2 for the crossover population). Non-haematological adverse events were generally lower with long-term ruxolitinib treatment than with best available therapy. Thromboembolic events were lower in the ruxolitinib group than the best available therapy group. There were two on-treatment deaths in the ruxolitinib group. One of these deaths was due to gastric adenocarcinoma, which was assessed by the investigator as related to ruxolitinib treatment., Interpretation: We showed that ruxolitinib is a safe and effective long-term treatment option for patients with polycythaemia vera who are resistant to or intolerant of hydroxyurea. Taken together, ruxolitinib treatment offers the first widely approved therapeutic alternative for this post-hydroxyurea patient population., Funding: Novartis Pharmaceuticals Corporation., (Copyright © 2020 Elsevier Ltd. All rights reserved.)

Background: The Janus kinase (JAK) inhibitor ruxolitinib is the only approved therapy for patients with symptomatic myelofibrosis. After ruxolitinib failure, however, there are few therapeutic options. We assessed the efficacy and safety of momelotinib, a JAK 1 and JAK 2 inhibitor, versus best available therapy (BAT) in patients with myelofibrosis who had suboptimal responses or haematological toxic effects with ruxolitinib., Methods: In this randomised, phase 3, open-label trial, patients were screened for eligibility from 52 clinical centres in Canada, France, Germany, Israel, Italy, Spain, the UK, and the USA. Patients who had myelofibrosis and previous ruxolitinib treatment for at least 28 days who either required red blood cell transfusions while on ruxolitinib or ruxolitinib dose reduction to less than 20 mg twice a day with at least one of grade 3 thrombocytopenia, anaemia, or bleeding at grade 3 or worse, with palpable spleen of at least 5 cm and without grade 2 or greater peripheral neuropathy were included in the study. Patients were randomly assigned (2:1) to either 24 weeks of open-label momelotinib 200 mg once a day or BAT (which could include ruxolitinib, chemotherapy, steroids, no treatment, or other standard interventions), after which all patients could receive extended momelotinib treatment. Patients were randomly assigned to treatment by an interactive web response system and the randomisation was stratified by transfusion dependence and by baseline total symptom score (TSS). Results were analysed on an intention-to-treat basis. The primary endpoint was a reduction by at least 35% in the spleen volume at 24 weeks compared with baseline. Safety analyses included adverse event monitoring. The trial is registered with ClinicalTrials.gov, number NCT02101268., Findings: Between June 19, 2014, and July 28, 2016, 156 patients were recruited to the study; 104 received momelotinib and 52 received BAT. BAT was ruxolitinib in 46 (89%) of 52 patients. 73 (70%) of 104 patients in the momelotinib group and 40 (77%) of 52 patients in the BAT group completed the 24-week treatment phase. Seven (7%) of 104 patients in the momelotinib group and three (6%) of 52 in the BAT group had a reduction in the spleen volume by at least 35% compared with baseline (proportion difference [Cochran-Mantel-Haenszel method], 0·01; 95% CI -0·09 to 0·10), p=0·90). The most common grade 3 or worse adverse events were anaemia (14 [14%] of 104 in the momelotinib group vs seven [14%] of 52 in the BAT group), thrombocytopenia (seven [7%] vs three [6%]), and abdominal pain (one [1%] vs three [6%]). Peripheral neuropathy occurred in 11 (11%) of 104 patients receiving momelotinib (one of which was grade 3) and in no patients in the BAT group. Serious events were reported for 36 (35%) patients in the momelotinib group and 12 (23%) of patients in the BAT group. Deaths due to adverse events were reported for six patients (6%) receiving momelotinib (acute myeloid leukaemia [n=2], respiratory failure [n=2, with one considered possibly related to momelotinib], cardiac arrest [n=1, considered possibly related to momelotinib], and bacterial sepsis [n=1]); and four patients (8%) receiving BAT (lung adenocarcinoma [n=1], myelofibrosis [n=1], and sepsis [n=2])., Interpretation: In patients with myelofibrosis previously treated with ruxolitinib, momelotinib was not superior to BAT for the reduction of spleen size by at least 35% compared with baseline., Funding: Gilead Sciences, Inc., (Copyright © 2018 Elsevier Ltd. All rights reserved.)

Background: Myelofibrosis is a chronic myeloproliferative neoplasm characterised by splenomegaly, cytopenias, bone marrow fibrosis, and debilitating symptoms including fatigue, weight loss, and bone pain. Mutations in Janus kinase-2 (JAK2) occur in approximately 50% of patients. The only approved JAK2 inhibitor for myelofibrosis is the dual JAK1 and JAK2 inhibitor, ruxolitinib. 58-71% of patients treated with ruxolitinib in clinical trials so far have not achieved the primary endpoint of 35% or more reduction in spleen volume from baseline assessed by MRI or CT. Furthermore, more than 50% of patients discontinue ruxolitinib treatment after 3-5 years. On the basis of this unmet need, we investigated the efficacy and safety of fedratinib, a JAK2-selective inhibitor, in patients with ruxolitinib-resistant or ruxolitinib-intolerant myelofibrosis., Methods: This single-arm, open-label, non-randomised, phase 2, multicentre study, done at 31 sites in nine countries, enrolled adult patients with a current diagnosis of intermediate or high-risk primary myelofibrosis, post-polycythaemia vera myelofibrosis, or post-essential thrombocythaemia myelofibrosis, found to be ruxolitinib resistant or intolerant after at least 14 days of treatment. Other main inclusion criteria were palpable splenomegaly (≥5 cm below the left costal margin), Eastern Cooperative Oncology Group performance status of 2 or less, and life expectancy of 6 months or less. Patients received oral fedratinib at a starting dose of 400 mg once per day, for six consecutive 28-day cycles. The primary endpoint was spleen response (defined as the proportion of patients with a ≥35% reduction in spleen volume as determined by blinded CT and MRI at a central imaging laboratory). We did the primary analysis in the per-protocol population only (patients treated with fedratinib, for whom a baseline and at least one post-baseline spleen volume measurement was available) and the safety analysis in all patients receiving at least one dose of fedratinib. This trial was registered with ClinicalTrials.gov, number NCT01523171., Findings: Between May 8, 2012, and Aug 29, 2013, 97 patients were enrolled and received at least one dose of fedratinib. Of 83 assessable patients, 46 (55%, 95% CI 44-66) achieved a spleen response. Common grade 3-4 adverse events included anaemia (37 [38%] of 97 patients) and thrombocytopenia (21 [22%] of 97), with 18 (19%) patients discontinuing due to adverse events. Seven (7%) patients died during the study, but none of the deaths was drug related. Suspected cases of Wernicke's encephalopathy in other fedratinib trials led to study termination., Interpretation: This phase 2 study met its primary endpoint, suggesting that patients with ruxolitinib-resistant or ruxolitinib-intolerant myelofibrosis might achieve significant clinical benefit with fedratinib, albeit at the cost of some potential toxicity, which requires further evaluation. Fedratinib development in this setting is currently being assessed., Funding: Sanofi., (Copyright © 2017 Elsevier Ltd. All rights reserved.)

Background: Available therapies for myelofibrosis can exacerbate cytopenias and are not indicated for patients with severe thrombocytopenia. Pacritinib, which inhibits both JAK2 and FLT3, induced spleen responses with limited myelosuppression in phase 1/2 trials. We aimed to assess the efficacy and safety of pacritinib versus best available therapy in patients with myelofibrosis irrespective of baseline cytopenias., Methods: This international, multicentre, randomised, phase 3 trial (PERSIST-1) was done at 67 sites in 12 countries. Patients with higher-risk myelofibrosis (with no exclusions for baseline anaemia or thrombocytopenia) were randomly assigned (2:1) to receive oral pacritinib 400 mg once daily or best available therapy (BAT) excluding JAK2 inhibitors until disease progression or unacceptable toxicity. Randomisation was stratified by risk category, platelet count, and region. Treatment assignments were known to investigators, site personnel, patients, clinical monitors, and pharmacovigilance personnel. The primary endpoint was spleen volume reduction (SVR) of 35% or more from baseline to week 24 in the intention-to-treat population as assessed by blinded, centrally reviewed MRI or CT. We did safety analyses in all randomised patients who received either treatment. Here we present the final data. This trial is registered with ClinicalTrials.gov, number NCT01773187., Findings: Between Jan 8, 2013, and Aug 1, 2014, 327 patients were randomly assigned to pacritinib (n=220) or BAT (n=107). Median follow-up was 23·2 months (IQR 14·8-28·7). At week 24, the primary endpoint of SVR of 35% or more was achieved by 42 (19%) patients in the pacritinib group versus five (5%) patients in the BAT group (p=0·0003). 90 patients in the BAT group crossed over to receive pacritinib at a median of 6·3 months (IQR 5·8-6·7). The most common grade 3-4 adverse events through week 24 were anaemia (n=37 [17%]), thrombocytopenia (n=26 [12%]), and diarrhoea (n=11 [5%]) in the pacritinib group, and anaemia (n=16 [15%]), thrombocytopenia (n=12 [11%]), dyspnoea (n=3 [3%]), and hypotension (n=3 [3%]) in the BAT group. The most common serious adverse events that occurred through week 24 were anaemia (10 [5%]), cardiac failure (5 [2%]), pyrexia (4 [2%]), and pneumonia (4 [2%]) with pacritinib, and anaemia (5 [5%]), sepsis (2 [2%]), and dyspnoea (2 [2%]) with BAT. Deaths due to adverse events were observed in 27 (12%) patients in the pacritinib group and 14 (13%) patients in the BAT group throughout the duration of the study., Interpretation: Pacritinib therapy was well tolerated and induced significant and sustained SVR and symptom reduction, even in patients with severe baseline cytopenias. Pacritinib could be a treatment option for patients with myelofibrosis, including those with baseline cytopenias for whom options are particularly limited., Funding: CTI BioPharma Corp., (Copyright © 2017 Elsevier Ltd. All rights reserved.)

While in RARS-T, JAK2V617F mutation is common and associated with good prognosis, the clinical and prognostic impact of this mutation in other MDS is unknown. We collected data from 132 non-RARS-T MDS with known JAK2V617F mutation status. JAK2V617F mutation was significantly correlated with lower progression to AML (p<.0011) and better overall survival (OS, p=.011). OS difference persisted after matching on age, sex, IPSS and % marrow blast (p=.031). Thus, in MDS other than RARS-T, JAK2V617F mutation may be associated with favorable outcome.