Explore the vast range of titles available.

The authors report on the clinical activity of a new oral inhibitor of Janus kinase 2 (JAK2) in patients with myelofibrosis. The drug improved a wide range of symptoms promptly, controlled them for >1 year, and appeared to inhibit disease progression to acute leukemia. Myelofibrosis is manifested as primary myelofibrosis, post–essential thrombocythemia myelofibrosis, or post–polycythemia vera myelofibrosis and is characterized by clinical signs (e.g., progressive anemia, bone marrow fibrosis, and splenomegaly) and a constellation of debilitating symptoms (fatigue, weakness, bone pain, a hypercatabolic state, and weight loss). 1 Survival in myelofibrosis is related to the number of risk factors and ranges from 2 to 4 years among patients with two or more risk factors (intermediate-2 or high risk) to 8 to 11 years among patients with no risk factors or one risk factor (intermediate-1 or low risk) (see Table 1A in the Supplementary Appendix, available with . . .

To share our 25 years of experience with patients with primary myelodysplastic syndromes (MDS) and to describe the natural history of the disease including presenting clinical and laboratory characteristics and long-term disease outcomes. One thousand consecutive patients with primary MDS evaluated at Mayo Clinic between January 1, 1989, and May 1, 2014, were considered. The Revised International Prognostic Scoring System and other risk models were applied for risk stratification. Separate analyses were conducted for patients diagnosed before 2005 (n=531) and after 2005 (n=469). Eighty-five percent of patients were older than 60 years (median age, 72 years), with 69% being men. The median follow-up period was 27 months (range, 0-300 months), during which time 808 (81%) deaths and 129 (13%) leukemic transformations were documented. Median survival and leukemic transformation rates were similar in patients diagnosed before or after 2005, despite the significantly higher use of hypomethylating agents in the latter group: 33 months vs 28 months (P=.46) and 13% vs 10% (P=.92), respectively. Revised International Prognostic Scoring System risk distribution was similar in patients diagnosed before or after 2005 (P=.23): 17% were categorized as very low, 36% low, 21% intermediate, 15% high, and 11% very high risk, with a median survival of 72, 43, 24, 18, and 7 months, respectively (P<.001). We found Revised International Prognostic Scoring System cytogenetic risk categorization to be suboptimal in its performance, whereas contemporary prognostic models were broadly similar in their performance. The poor outcome in patients with MDS does not appear to have improved over time. Current risk stratification systems for MDS are not substantially different from each other. There is a dire need for drugs that are truly disease modifying and risk models that incorporate prognostically relevant mutations.

To share our 25 years of experience with patients with primary myelodysplastic syndromes (MDS) and to describe the natural history of the disease including presenting clinical and laboratory characteristics and long-term disease outcomes. One thousand consecutive patients with primary MDS evaluated at Mayo Clinic between January 1, 1989, and May 1, 2014, were considered. The Revised International Prognostic Scoring System and other risk models were applied for risk stratification. Separate analyses were conducted for patients diagnosed before 2005 (n=531) and after 2005 (n=469). Eighty-five percent of patients were older than 60 years (median age, 72 years), with 69% being men. The median follow-up period was 27 months (range, 0-300 months), during which time 808 (81%) deaths and 129 (13%) leukemic transformations were documented. Median survival and leukemic transformation rates were similar in patients diagnosed before or after 2005, despite the significantly higher use of hypomethylating agents in the latter group: 33 months vs 28 months (P=.46) and 13% vs 10% (P=.92), respectively. Revised International Prognostic Scoring System risk distribution was similar in patients diagnosed before or after 2005 (P=.23): 17% were categorized as very low, 36% low, 21% intermediate, 15% high, and 11% very high risk, with a median survival of 72, 43, 24, 18, and 7 months, respectively (P<.001). We found Revised International Prognostic Scoring System cytogenetic risk categorization to be suboptimal in its performance, whereas contemporary prognostic models were broadly similar in their performance. The poor outcome in patients with MDS does not appear to have improved over time. Current risk stratification systems for MDS are not substantially different from each other. There is a dire need for drugs that are truly disease modifying and risk models that incorporate prognostically relevant mutations.

Ruxolitinib (INCB018424) is a JAK1 and JAK2 inhibitor recently evaluated for the treatment of myelofibrosis (MF) in early- and advanced-phase clinical trials. In 2 recent communications that focused on short-term and long-term ruxolitinib treatment outcome, respectively, the drug was shown to be effective in controlling constitutional symptoms and splenomegaly but was also associated with important adverse effects, including moderate to severe thrombocytopenia and anemia. The most recent of the 2 communications focused on 51 Mayo Clinic patients who participated in the original phase 1/2 ruxolitinib clinical trial and highlighted a high treatment discontinuation rate (92% after a median time of 9.2 months), primarily for loss of treatment benefit but also because of drug-associated adverse effects. The report also discussed the occurrence of sometimes severe withdrawal symptoms during ruxolitinib treatment discontinuation. This “ruxolitinib withdrawal syndrome” was characterized by acute relapse of disease symptoms, accelerated splenomegaly, worsening of cytopenias, and occasional hemodynamic decompensation, including a septic shocklike syndrome. In the current sponsor-independent analysis, we describe the details of these events in 5 severely affected cases (11%) among 47 Mayo Clinic patients with MF in whom ruxolitinib therapy had been discontinued. Our experience calls for full disclosure of the ruxolitinib withdrawal syndrome to patients with MF before initiating ruxolitinib therapy, and treatment discontinuation must be done under close physician supervision and preferably in a tapering schedule.

Key Points Acquisition of the constitutively active Janus kinase 2 (JAK2)V617F mutation occurs in almost all patients with polycythaemia vera (PV) and in a significant number of patients with essential thombocythaemia (ET) and primary myelofibrosis (PMF). JAK2V617F is a constitutively active tyrosine kinase that activates signal transducer and activator of transcription (Stat), mitogen activated protein kinase (MAPK) and phosphotidylinositol 3-kinase (PI3K) signalling pathways, and transforms haematopoietic progenitors. The identification of JAK2V617F has had a significant impact on the classification, diagnosis and prognosis of PV, ET and PMF. Gain-of-function mutations in JAK2 exon 12 and in the thrombopoietin receptor are observed in some patients with JAK2V617F-negative myeloproliferative disorders (MPD), suggesting constitutive activation of JAK2 signalling is central to the pathogenesis of PV, ET and PMF. The presence of a single disease allele in related, but clinically distinct MPD indicates that additional genetic events contribute to the pathogenesis of these disorders. The discovery of JAK2V617F has led to the development of selective JAK2 inhibitors for the treatment of PV, ET and PMF. The myeloproliferative disorders (MPD) polycythaemia vera (PV), essential thombocythaemia (ET), and primary myelofibrosis (PMF) are clonal disorders of multipotent haematopoietic progenitors, and most patients with these diseases acquire a single point mutation in the cytoplasmic tyrosine kinase JAK2 (JAK2V617F). What are the implications of these findings for MPD? The myeloproliferative disorders polycythaemia vera (PV), essential thombocythaemia (ET), and primary myelofibrosis (PMF) are clonal disorders of multipotent haematopoietic progenitors. The genetic cause of these diseases was not known until 2005, when several independent groups demonstrated that most patients with PV, ET and PMF acquire a single point mutation in the cytoplasmic tyrosine kinase JAK2 (JAK2V617F) . These discoveries have changed the landscape for diagnosis and classification of PV, ET and PMF, and show the ability of genomic technologies to identify new molecular targets in human malignancies with pathogenetic, diagnostic and therapeutic significance.

Acquired eosinophilia is operationally categorized into secondary, clonal, and idiopathic types. Causes of secondary eosinophilia include parasite infections, allergic or vasculitis conditions, drugs, and lymphoma. Clonal eosinophilia is distinguished from idiopathic eosinophilia by the presence of histologic, cytogenetic, or molecular evidence of an underlying myeloid malignancy. The World Health Organization classification system for hematologic malignancies recognizes 2 distinct subcategories of clonal eosinophilia: chronic eosinophilic leukemia, not otherwise specified and myeloid/lymphoid neoplasms with eosinophilia and mutations involving platelet-derived growth factor receptor α/β or fibroblast growth factor receptor 1. Clonal eosinophilia might also accompany other World Health Organization—defined myeloid malignancies, including chronic myelogenous leukemia, myelodysplastic syndromes, chronic myelomonocytic leukemia, and systemic mastocytosis. Hypereosinophilic syndrome, a subcategory of idiopathic eosinophilia, is defined by the presence of a peripheral blood eosinophil count of 1.5 × 10 9/L or greater for at least 6 months (a shorter duration is acceptable in the presence of symptoms that require eosinophil-lowering therapy), exclusion of both secondary and clonal eosinophilia, evidence of organ involvement, and absence of phenotypically abnormal and/or clonal T lymphocytes. The presence of the latter defines lymphocytic variant hyper eosinophilia, which is best classified under secondary eosinophilia. In the current review, we provide a simplified algorithm for distinguishing the various causes of clonal and idiopathic eosinophilia and discuss current therapy, including new drugs (imatinib mesylate, alemtuzumab, and mepolizumab).

Loss-of-function TET2 mutations (TET2MT) are frequent early clonal events in myeloid neoplasms and are thought to confer a fitness advantage to hematopoietic precursors. This large, multi-institutional study (n = 1084), investigated the TET2 mutational landscape and prognostic implications of the number, type, and location of TET2MT and the epistatic relationship with other somatic events in chronic myelomonocytic leukemia (CMML). Nine hundred and forty-two TET2MT were identified in 604 (56%) patients, of which 710 (75%) were predicted to be truncating (involving the catalytic domain). Three hundred and sixteen (29%) patients had ≥1 TET2MT, with 28%, 1%, and 0.2% harboring 2, 3, and 5 mutations, respectively. In comparison to TET2WT, TET2MT patients were older in age, more likely to have dysplastic CMML, a higher number of co-occurring mutations, and lower-risk stratification. Importantly, TET2MT were associated with a survival advantage (49 vs. 30 months, p < 0.0001), especially in the context of multiple TET2MT (≥2; 57 months, p < 0.001), and truncating TET2MT (51 months, p < 0.001). In addition, the adverse prognostic impact of ASXL1MT was partially mitigated by concurrent TET2MT, with the ASXL1WT/TET2MT genotype having better outcomes and resulting in further risk stratification of ASXL1 inclusive CMML prognostic models, in comparison to ASXL1MT alone.

An inhibitor of Aurora kinase promotes megakaryocytic differentiation of cells from patients with primary myelofibrosis and shows antifibrotic effects in mouse models of this disease. Primary myelofibrosis (PMF) is characterized by bone marrow fibrosis, myeloproliferation, extramedullary hematopoiesis, splenomegaly and leukemic progression. Moreover, the bone marrow and spleens of individuals with PMF contain large numbers of atypical megakaryocytes that are postulated to contribute to fibrosis through the release of cytokines, including transforming growth factor (TGF)-β. Although the Janus kinase inhibitor ruxolitinib provides symptomatic relief, it does not reduce the mutant allele burden or substantially reverse fibrosis. Here we show through pharmacologic and genetic studies that aurora kinase A (AURKA) represents a new therapeutic target in PMF. Treatment with MLN8237, a selective AURKA inhibitor, promoted polyploidization and differentiation of megakaryocytes with PMF-associated mutations and had potent antifibrotic and antitumor activity in vivo in mouse models of PMF. Moreover, heterozygous deletion of Aurka was sufficient to ameliorate fibrosis and other PMF features in vivo . Our data suggest that megakaryocytes drive fibrosis in PMF and that targeting them with AURKA inhibitors has the potential to provide therapeutic benefit.

To share our decades of experience with primary myelofibrosis and underscore the importance of outcomes research studies in designing clinical trials and interpreting their results. One thousand consecutive patients with primary myelofibrosis seen at Mayo Clinic between November 4, 1977, and September 1, 2011, were considered. The International Prognostic Scoring System (IPSS), dynamic IPSS (DIPSS), and DIPSS-plus were applied for risk stratification. Separate analyses were included for patients seen at time of referral (N=1000), at initial diagnosis (N=340), and within or after 1 year of diagnosis (N=660). To date, 592 deaths and 68 leukemic transformations have been documented. Parameters at initial diagnosis vs time of referral included median age (66 vs 65 years), male sex (61% vs 62%), red cell transfusion need (24% vs 38%), hemoglobin level less than 10 g/dL (38% vs 54%), platelet count less than 100 × 10 9/L (18% vs 26%), leukocyte count more than 25 × 10 9/L (13% vs 16%), marked splenomegaly (21% vs 31%), constitutional symptoms (29% vs 34%), and abnormal karyotype (31% vs 41%). Mutational frequencies were 61% for JAK2V617F, 8% for MPLW515, and 4% for IDH1/2. DIPSS-plus risk distributions at time of referral were 10% low, 15% intermediate-1, 37% intermediate-2, and 37% high. The corresponding median survivals were 17.5, 7.8, 3.6, and 1.8 years vs 20.0, 14.3, 5.3, and 1.7 years for patients younger than 60 years of age. Compared with both DIPSS and IPSS, DIPSS-plus showed better discrimination among risk groups. Five-year leukemic transformation rates were 6% and 21% in low- and high-risk patients, respectively. The current document should serve as a valuable resource for patients and physicians and provides context for the design and interpretation of clinical trials.