Idiopathic erythrocytosis: A diagnostic and management challenge with emerging areas for exploration.

Despite published algorithms for approaching the work-up of erythrocytosis, a significant proportion of patients are left with uncertainty as to its aetiology and prognosis. The term 'idiopathic erythrocytosis' (IE) is applied when known primary and secondary aetiologies have been ruled out. However, the assignment of secondary aetiologies is not always straightforward or evidence based, which can lead to misdiagnosis and heterogeneity in cohort studies. Furthermore, new studies have identified germline or somatic mutations that may affect prognosis. Epidemiological and cohort data are inconsistent as to whether IE increases the risk for complications such as arterial and venous thromboembolism, clonal transformation or comorbid conditions. Randomized trials assessing the role of phlebotomy for long-term management of IE have not been performed, so treatment remains a vexing problem for clinicians. Standardization of terminology and testing strategies, including comprehensive genetic screening in clinical research, are key to refining our understanding of IE.

A randomized phase 3 trial of interferon-α vs hydroxyurea in polycythemia vera and essential thrombocythemia.

The goal of therapy for patients with essential thrombocythemia (ET) and polycythemia vera (PV) is to reduce thrombotic events by normalizing blood counts. Hydroxyurea (HU) and interferon-α (IFN-α) are the most frequently used cytoreductive options for patients with ET and PV at high risk for vascular complications. Myeloproliferative Disorders Research Consortium 112 was an investigator-initiated, phase 3 trial comparing HU to pegylated IFN-α (PEG) in treatment-naïve, high-risk patients with ET/PV. The primary endpoint was complete response (CR) rate at 12 months. A total of 168 patients were treated for a median of 81.0 weeks. CR for HU was 37% and 35% for PEG (P = .80) at 12 months. At 24 to 36 months, CR was 20% to 17% for HU and 29% to 33% for PEG. PEG led to a greater reduction in JAK2V617F at 24 months, but histopathologic responses were more frequent with HU. Thrombotic events and disease progression were infrequent in both arms, whereas grade 3/4 adverse events were more frequent with PEG (46% vs 28%). At 12 months of treatment, there was no significant difference in CR rates between HU and PEG. This study indicates that PEG and HU are both effective treatments for PV and ET. With longer treatment, PEG was more effective in normalizing blood counts and reducing driver mutation burden, whereas HU produced more histopathologic responses. Despite these differences, both agents did not differ in limiting thrombotic events and disease progression in high-risk patients with ET/PV. This trial was registered at www.clinicaltrials.gov as #NCT01259856.

Clinical and pathological features of clonal cytopenia of undetermined significance presenting with isolated thrombocytopenia (CCUS-IT).

BACKGROUND: Clonal cytopenia of undetermined significance (CCUS) is defined as somatic mutations of myeloid malignancy-associated genes in the blood or bone marrow with one or more persistent unexplained cytopenias that do not meet diagnostic criteria for a defined myeloid neoplasm. CCUS with isolated thrombocytopenia (CCUS-IT) is rare. METHODS: This is a retrospective case series of patients with prolonged isolated thrombocytopenia, a pathogenic mutation on a myeloid molecular panel, and a bone marrow biopsy with morphologic atypia below the WHO-defined diagnostic threshold for dysplasia. RESULTS: Five male patients were identified with a median age at CCUS-IT diagnosis of 61 years (56-74). Median duration of thrombocytopenia prior to CCUS-IT diagnosis was 4 years (3-12), and median platelet count at CCUS-IT diagnosis was 41 × 103 /µL (26-80). All patients had megakaryocytic hyperplasia and megakaryocytes with hyperchromasia and high nuclear-cytoplasmic ratio. Pathogenic SRSF2 mutations were identified in all 5 patients with median variant allele frequency of 36% (28%-50%). Three patients were treated with IVIg and/or steroids with no response; one of three responded to thrombopoietin receptor agonists. Three patients progressed to MDS and one to AML. DISCUSSION: We describe the clinicopathological features of CCUS-IT which can mimic immune thrombocytopenia.

The TEMPI syndrome.

The TEMPI syndrome is a rare and acquired disorder characterized by 5 salient features, which compose its name: (1) telangiectasias; (2) elevated erythropoietin and erythrocytosis; (3) monoclonal gammopathy; (4) perinephric fluid collections; and (5) intrapulmonary shunting. Complete resolution of symptoms following treatment with plasma cell-directed therapy supports the hypothesis that the monoclonal antibody is causal and pathogenic. Understanding the basis of the TEMPI syndrome will depend on the identification of additional patients and a coordinated international effort.

Oral cedazuridine/decitabine for MDS and CMML: a phase 2 pharmacokinetic/pharmacodynamic randomized crossover study.

This phase 2 study was designed to compare systemic decitabine exposure, demethylation activity, and safety in the first 2 cycles with cedazuridine 100 mg/decitabine 35 mg vs standard decitabine 20 mg/m2 IV. Adults with International Prognostic Scoring System intermediate-1/2- or high-risk myelodysplastic syndromes (MDS) or chronic myelomonocytic leukemia (CMML) were randomized 1:1 to receive oral cedazuridine/decitabine or IV decitabine in cycle 1, followed by crossover to the other treatment in cycle 2. All patients received oral cedazuridine/decitabine in subsequent cycles. Cedazuridine and decitabine were given initially as separate capsules in a dose-confirmation stage and then as a single fixed-dose combination (FDC) tablet. Primary end points: mean decitabine systemic exposure (geometric least-squares mean [LSM]) of oral/IV 5-day area under curve from time 0 to last measurable concentration (AUClast), percentage long interspersed nuclear element 1 (LINE-1) DNA demethylation for oral cedazuridine/decitabine vs IV decitabine, and clinical response. Eighty patients were randomized and treated. Oral/IV ratios of geometric LSM 5-day AUClast (80% confidence interval) were 93.5% (82.1-106.5) and 97.6% (80.5-118.3) for the dose-confirmation and FDC stages, respectively. Differences in mean %LINE-1 demethylation between oral and IV were ≤1%. Clinical responses were observed in 48 patients (60%), including 17 (21%) with complete response. The most common grade ≥3 adverse events regardless of causality were neutropenia (46%), thrombocytopenia (38%), and febrile neutropenia (29%). Oral cedazuridine/decitabine (100/35 mg) produced similar systemic decitabine exposure, DNA demethylation, and safety vs decitabine 20 mg/m2 IV in the first 2 cycles, with similar efficacy. This study is registered at www.clinicaltrials.gov as #NCT02103478.

Persistent leukocytosis in polycythemia vera is associated with disease evolution but not thrombosis.

There are unresolved questions regarding the association between persistent leukocytosis and risk of thrombosis and disease evolution in polycythemia vera (PV), as much of the published literature on the topic does not appropriately use repeated-measures data or time-dependent modeling to answer these questions. To address this knowledge gap, we analyzed a retrospective database of 520 PV patients seen at 10 academic institutions across the United States. Taking hematologic laboratory data at ∼3-month intervals (or as available) for all patients for duration of follow-up, we used group-based trajectory modeling to identify latent clusters of patients who follow distinct trajectories with regard to their leukocyte, hematocrit, and platelet counts over time. We then tested the association between trajectory membership and hazard of 2 major outcomes: thrombosis and disease evolution to myelofibrosis, myelodysplastic syndrome, or acute myeloid leukemia. Controlling for relevant covariates, we found that persistently elevated leukocyte trajectories were not associated with the hazard of a thrombotic event (P = .4163), but were significantly associated with increased hazard of disease evolution in an ascending stepwise manner (overall P = .0002). In addition, we found that neither hematocrit nor platelet count was significantly associated with the hazard of thrombosis or disease evolution.

Treatment of Cancer-Associated Venous Thromboembolism with Low-Molecular-Weight Heparin or Direct Oral Anticoagulants: Patient Selection, Controversies, and Caveats.

The treatment of venous thromboembolism (VTE) in patients with cancer is challenging because these patients have increased risks of both recurrent VTE and major bleeding, along with patient-specific and cancer-related factors that influence the approach to treatment. Historically, anticoagulant therapy with low-molecular-weight heparin (LMWH), given for both initial and long-term treatment, has been the preferred approach recommended by practice guidelines. Most recently, the National Comprehensive Cancer Network (NCCN) guidelines indicate that the direct oral anticoagulants (DOACs) apixaban, edoxaban, or rivaroxaban are preferred for patients without gastric or gastroesophageal lesions. DOACs have been associated with an increased risk of major bleeding in patients with gastrointestinal and possibly genitourinary cancers, and DOACs should either not be used (especially in those with intact intraluminal tumors) or be used with caution in patients with these cancers. Fatal or life-threatening bleeding occurs with similar frequency with DOACs or LMWH, and most major bleeding with DOACs can be managed with transfusion and standard measures. The patient's willingness and ability to comply with LMWH injections, and their treatment preference, should also be considered. Patients with cancer who have VTE should be treated with anticoagulation for a minimum of 6 months. Anticoagulation should be continued indefinitely while cancer is active or under treatment or if there are persistent risk factors for recurrent VTE. This article summarizes the evidence from clinical trials of LMWH and DOACs that underpins the NCCN guideline recommendations, addresses several controversies and caveats regarding anticoagulant treatment, and offers evidence-based, practical suggestions on patient selection for treatment with DOACs. IMPLICATIONS FOR PRACTICE: Several randomized trials support the addition of direct oral anticoagulants (DOACs) to the therapeutic armamentarium for cancer-associated venous thromboembolism (VTE). These agents come with unique risks and patient- and cancer-specific variables that must be evaluated during the course of a patient's cancer care. This narrative review discusses findings from clinical trials of low-molecular-weight heparin and DOACs for the treatment of cancer-associated VTE, evidence that supports the recent National Comprehensive Cancer Network guideline recommendations. A personalized approach to treatment is proposed that addresses patient selection for treatment with DOACs, factors that influence efficacy and safety, controversies and caveats, and suggestions for their resolution in clinical practice.

Extrapulmonary manifestations of severe acute respiratory syndrome coronavirus-2 infection.

Coronavirus disease 2019, the infectious disease caused by severe acute respiratory syndrome coronavirus-2, has resulted in a global pandemic with unprecedented health, societal, and economic impact. The disease often manifests with flu-like symptoms and is dominated by pulmonary complications, but widely diverse clinical manifestations involving multiple organ systems can result. We posit that viral tropism and the aberrant host immune response mediate the protean findings and severity in this disease. In general, extrapulmonary manifestations are a harbinger of or contemporaneously associate with disease progression, but in the case of some extrapulmonary findings (gastrointestinal and dermatologic), may track with milder disease. The precise underlying pathophysiological mechanisms remain incompletely elucidated, and additional immune phenotyping studies are warranted to reveal early correlates of disease outcomes and novel therapeutic targets.

Telomerase Variants in Patients with Cirrhosis Awaiting Liver Transplantation.

Telomeres are repetitive DNA sequences that protect the ends of linear chromosomes, and they are maintained by a ribonucleoprotein complex called telomerase. Variants in genes encoding for telomerase components have been associated with a spectrum of disease in the lung, skin, bone marrow, and liver. Mutations in the telomerase reverse transcriptase and telomerase RNA component genes have been observed at a higher prevalence in patients with liver disease compared with the general population; however, the presence of variants in other components of the telomerase complex and their impact on clinical outcomes has not been explored. We evaluated 86 patients with end-stage liver disease for variants in an expanded panel of eight genes, and found that 17 patients (20%) had likely deleterious variants by in silico analysis. Seven unique likely deleterious variants were identified in the regulator of telomere elongation helicase 1 (RTEL1) gene that encodes for a DNA helicase important in telomere maintenance and genomic stability. In gene burden association analysis of their clinical data, the presence of any RTEL1 variant was associated with a 29% lower baseline white blood cell count (95% confidence interval [CI], -7% to -46%; P Value = 0.01) compared with patients without RTEL1 variants, and the presence of any exonic missense RTEL1 variant was associated with a 42% lower baseline platelet count (95% CI, -5% to -65%: P Value = 0.03). The presence of any telomerase variant was associated with an increased number of readmissions within 1 year after transplantation demonstrated by an incident rate ratio (IRR) of 3.15 (95% CI, 1.22 to 8.57). No association with survival was observed. Conclusion: Among patients who underwent liver transplantation, the presence of any exonic missense variant was associated with a longer postoperative length of stay with an IRR of 2.16 (95% CI, 1.31 to 3.68).

A Retrospective Study of the Combination of Rituximab, Cyclophosphamide and Dexamethasone for the Treatment of Relapsed/Refractory Warm Antibody Autoimmune Hemolytic Anemia.

The combination of rituximab, cyclophosphamide, and dexamethasone (RCD) is highly effective in the treatment of warm autoimmune hemolytic anemia (WAIHA) associated with chronic lymphocytic leukemia (CLL). We treated a cohort of patients with relapsed/refractory WAIHA, without CLL, with RCD. The primary objective was to evaluate the overall response (OR) of RCD therapy. Complete response (CR) was defined as a hemoglobin (Hgb) ≥12 g/dL. Partial response (PR) was defined as Hgb 10-11.9 g/dL or ≥2 g/dL increase in Hgb. Sustained response was defined as Hgb ≥10 g/dL with no treatment changes. A total of 16 patients with relapsed/refractory WAIHA received RCD (7 primary WAIHA, 9 secondary WAIHA) for a median of 4 cycles (range: 2-6). The median pretreatment Hgb was 10.0 g/dL (range: 4.3-12.2). The median best Hgb achieved was 12.5 g/dL (range: 10.6-15.1) with a median of 2 cycles until best Hgb response. The OR was 94% (11 CR, 4 PR). Two immunocompromised patients were admitted for infections during RCD treatment. There were no deaths during the treatment or follow-up period. Following a response to RCD, 4 patients received noncorticosteroid immune modulation therapy and 4 patients continued on corticosteroid therapy. Seven patients received no additional treatment.

Integrative Epigenetic Analysis Reveals Therapeutic Targets to the DNA Methyltransferase Inhibitor Guadecitabine (SGI-110) in Hepatocellular Carcinoma.

There is an urgent need to develop more effective therapies for hepatocellular carcinoma (HCC) because of its aggressiveness. Guadecitabine (SGI-110) is a second-generation DNA methyltransferase inhibitor (DNMTi), which is currently in clinical trials for HCC and shows greater stability and performance over first-generation DNMTis. In order to identify potential therapeutic targets of SGI-110 for clinical trials, HCC cell lines (SNU398, HepG2, and SNU475) were used to evaluate the effects of transient SGI-110 treatment by an integrative analysis of DNA methylation, nucleosome accessibility, gene expression profiles, and its clinical relevance by comparison to The Cancer Genome Atlas (TCGA) HCC clinical data. Each HCC cell line represents a different DNA methylation subtype of primary HCC tumors based on TCGA data. After SGI-110 treatment, all cell lines were sensitive to SGI-110 with prolonged antiproliferation effects. Expression of up-regulated genes, including tumor suppressors, was positively correlated with nucleosome accessibility and negatively correlated with gene promoter DNA methylation. Alternatively, expression of down-regulated genes, such as oncogenes, was negatively correlated with nucleosome accessibility and positively correlated with gene body DNA methylation. SGI-110 can also act as a dual inhibitor to down-regulate polycomb repressive complex 2 (PRC2) genes by demethylating their gene bodies, resulting in reactivation of PRC2 repressed genes without involvement of DNA methylation. Furthermore, it can up-regulate endogenous retroviruses to reactivate immune pathways. Finally, about 48% of frequently altered genes in primary HCC tumors can be reversed by SGI-110 treatment. CONCLUSION: Our integrative analysis has successfully linked the antitumor effects of SGI-110 to detailed epigenetic alterations in HCC cells, identified potential therapeutic targets, and provided a rationale for combination treatments of SGI-110 with immune checkpoint therapies.

Ethnic and racial difference in Helicobacter pylori infection in patients with immune thrombocytopenia treated at a major urban medical center.

Immune thrombocytopenia (ITP) is an autoimmune disorder with a complex immunopathology and pathogenesis characterized by thrombocytopenia and bleeding manifestations. The disorder is separated into primary (idiopathic) ITP and secondary ITP, when associated with other immune or lymphoproliferative disorders and certain chronic infections. Helicobacter pylori (H. pylori) is a recognized bacterial cause of ITP. In regions with high prevalence of infection, bacterial eradication has resulted in improvement in platelet count. However, the prevalence of H. pylori infection and response to antimicrobial therapy in North American ITP patients is reportedly low. We evaluated the prevalence of H. pylori infection in ITP patients diagnosed and treated at a large urban medical center. Eighty-two patients were screened for H. pylori, by stool antigen (n = 54), H. pylori breath test (n = 11), and H. pylori antibodies (n = 16), of which 15 (18.3%) were white non-Hispanic (WNH), 55 (67%) Hispanic (H), 8 (9.8%) Asian (A), and 4 (4.9%) African-American (AA). Of the screened patients, 36/82 (43.9%) tested positive for H. pylori. The prevalence of H. pylori infection within the represented ethnic groups was 2/15 (13%) WNH, 29/55 (52.7%) H, 3/8 (37.5%) A, and 2/4 (50%) AA. There was a significant difference in prevalence of infection comparing WNH and H patients (p = 0.007). There were 36 treated patients, with H. pylori eradication documented in 26 patients. Fifteen of the 26 patients were evaluable for response with 8 of 15 (53%) having clinical responses, 6 complete responses, and 2 partial responses. Our study demonstrates an increased prevalence of H. pylori infection in the Hispanic ITP population with a reasonable platelet response among patients with H. pylori eradication.

Dose, schedule, safety, and efficacy of guadecitabine in relapsed or refractory acute myeloid leukemia.

BACKGROUND: Outcomes for patients with relapsed or refractory acute myeloid leukemia (AML) are poor. Guadecitabine, a next-generation hypomethylating agent, could be useful in treating such patients. METHODS: In this multicenter, open-label, phase 2 dose-expansion study, AML patients from 10 North American medical centers were first randomized (1:1) to receive subcutaneous guadecitabine at 60 or 90 mg/m2 on 5 consecutive days in each 28-day cycle (5-day regimen). Subsequently, another cohort was treated for 10 days with 60 mg/m2 (10-day regimen). RESULTS: Between June 15, 2012, and August 19, 2013, 108 patients with previously treated AML consented to enroll in the study, and 103 of these patients were treated; 5 patients did not receive the study treatment. A total of 103 patients were included in the safety and efficacy analyses (24 and 26 patients who were randomly assigned to 60 and 90 mg/m2 /d, respectively [5-day regimen] and 53 patients who were assigned to 60 mg/m2 /d [10-day regimen]). The 90 mg/m2 dose showed no benefit in clinical outcomes in comparison with 60 mg/m2 in the randomized cohort. Composite complete response (CRc) and complete response (CR) rates were higher with the 10-day regimen versus the 5-day regimen (CRc, 30.2% vs 16.0%; P = .1061; CR, 18.9% vs 8%; P = .15). Adverse events (grade ≥ 3) were mainly hematologic, with a higher incidence on the 10-day regimen. Early all-cause mortality was low and similar between regimens. Twenty patients (8 on the 5-day regimen and 12 on the 10-day regimen) were bridged to hematopoietic cell transplantation. CONCLUSIONS: Guadecitabine has promising clinical activity and an acceptable safety profile and thus warrants further development in this population. Cancer 2018;124:325-34. © 2017 The Authors. Cancer published by Wiley Periodicals, Inc. on behalf of American Cancer Society. This is an open access article under the terms of the Creative Commons Attribution NonCommercial License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited and is not used for commercial purposes.

Guadecitabine (SGI-110) in treatment-naive patients with acute myeloid leukaemia: phase 2 results from a multicentre, randomised, phase 1/2 trial.

BACKGROUND: The hypomethylating drugs azacitidine and decitabine have shown efficacy in myelodysplastic syndromes and acute myeloid leukaemia, but complete tumour responses are infrequent and of short duration, possibly because of the short half-lives and suboptimal bone marrow exposure of the drugs. Guadecitabine, a next-generation hypomethylating drug, has a longer half-life and exposure than its active metabolite decitabine. A phase 1 study established 60 mg/m2 guadecitabine for 5 days as an effective treatment schedule. In this phase 2 study, we aimed to assess the safety and activity of two doses and schedules of guadecitabine in older (≥65 years) patients with treatment-naive acute myeloid leukaemia who were not candidates for intensive chemotherapy. METHODS: We did a multicentre, randomised, open-label, phase 1/2 study of guadecitabine in cohorts of patients with treatment-naive acute myeloid leukaemia, relapsed or refractory acute myeloid leukaemia, and myelodysplastic syndromes; here we report the phase 2 results from the cohort of treatment-naive patients with acute myeloid leukaemia. We included patients aged at least 65 years from 14 US medical centres (hospitals and specialist cancer clinics) who were not candidates for intensive chemotherapy and randomly assigned them (1:1) using a computer algorithm (for dynamic randomisation) to guadecitabine 60 or 90 mg/m2 on days 1-5 (5-day schedule) of a 28-day treatment cycle. Treatment allocation was not masked. We also assigned additional patients to guadecitabine 60 mg/m2 in a 10-day schedule in a 28-day treatment cycle after a protocol amendment. The primary endpoint was composite complete response (complete response, complete response with incomplete platelet recovery, or complete response with incomplete neutrophil recovery regardless of platelets). Response was assessed in all patients (as-treated) who received at least one dose of guadecitabine. We present the final analysis, although at the time of the database lock, 15 patients were still in follow-up for overall survival. This study is registered with ClinicalTrials.gov, number NCT01261312. FINDINGS: Between Aug 24, 2012, and Sept 15, 2014, 107 patients were enrolled: 54 on the 5-day schedule (26 randomly assigned to 60 mg/m2 and 28 to 90 mg/m2) and 53 were assigned to the 10-day schedule. Median age was 77 years (range 62-92), and median follow-up was 953 days (IQR 721-1040). All treated patients were assessable for a response. The number of patients who achieved a composite complete response did not differ between dose groups or schedules (13 [54%, 95% CI 32·8-74·4] with 60 mg/m2 on the 5-day schedule; 16 [59%; 38·8-77·6] with 90 mg/m2 on the 5-day schedule; and 26 [50%, 35·8-64·2] with 60 mg/m2 on the 10-day schedule). The most frequent grade 3 or worse adverse events, regardless of relationship to treatment, were febrile neutropenia (31 [61%] of 51 patients on the 5-day schedule vs 36 [69%] of 52 patients on the 10-day schedule), thrombocytopenia (25 [49%] vs 22 [42%]), neutropenia (20 [39%] vs 18 [35%]), pneumonia (15 [29%] vs 19 [37%]), anaemia (15 [29%] vs 12 [23%]), and sepsis (eight [16%] vs 14 [27%]). The most common serious adverse events, regardless of relationship to treatment, for the 5-day and 10-day schedules, respectively, were febrile neutropenia (27 [53%] vs 25 [48%]), pneumonia (14 [27%] vs 16 [31%]), and sepsis (eight [16%] vs 14 [27%]). 23 (22%) patients died because of adverse events (mainly from sepsis, eight [8%]; and pneumonia, five [5%]); four deaths were from adverse events deemed treatment-related (pneumonia, two [2%]; multiorgan failure, one [1%]; and sepsis, one [1%], all in the 10-day cohort). INTERPRETATION: More than half of older treatment-naive patients with acute myeloid leukaemia achieved a composite complete response with guadecitabine at all drug doses and schedules investigated, with tolerable toxicity. The recommended guadecitabine regimen for this population is 60 mg/m2 in a 5-day schedule. A phase 3 study in this patient population is ongoing (NCT02348489) to assess guadecitabine 60 mg/m2 in a 5-day schedule versus standard of care. FUNDING: Astex Pharmaceuticals and Stand Up To Cancer.

How I treat incidental pulmonary embolism.

The identification of pulmonary embolism (PE) on computed tomography scans performed for indications other than identification of thromboembolism is a growing clinical problem that has not been adequately addressed by prospective treatment trials. The prevalence of incidentally detected PE ranges from 1% to 4% in unselected populations, with higher rates among hospital inpatients and patients with cancer. Current guidelines recommend using the same approach to type and duration of anticoagulation as is used for patients with suspected PE. Available data regarding the significance of symptomatic subsegmental PE (SSPE) are conflicting, making it difficult to draw conclusions about the appropriate treatment of incidentally detected SSPE, for which the data are sparse. Among cancer patients, the bulk of available data suggest that incidental SSPE is associated with recurrent venous thromboembolism and, when symptomatic, may adversely impact survival. Here, the topic is reviewed utilizing 3 clinical cases, each of which is followed by a discussion of salient features and then by treatment recommendations.

Management of the Incidental Pulmonary Embolism.

OBJECTIVE: The incidental pulmonary embolism (PE) is being identified at an increasing rate because of use of MDCT and presents a management challenge because of a lack of prospective data. Most clinicians treat patients with proximal or segmental incidental PE in the same manner as patients with suspected PE. CONCLUSION: The treatment of subsegmental PE may be guided by an assessment of patient symptoms, risk factors for recurrent venous thrombosis, and concomitant deep venous thrombosis.

Autoimmune Myelofibrosis: Clinical Features, Course, and Outcome.

BACKGROUND: Autoimmune myelofibrosis (AIMF) is an underrecognized cause of nonmalignant bone marrow fibrosis which occurs in the presence or absence of a defined systemic autoimmune disease. Patients with AIMF present with cytopenias and autoantibodies, and have a distinctive nonclonal myelofibrosis on bone marrow examination. AIMF is distinguished from primary myelofibrosis by the absence of splenomegaly, eosinophilia, or basophilia, and the absence of abnormal myeloid, erythroid, or megakaryocytic morphology. OBJECTIVES: The objective of the study was to describe the clinical presentation and outcomes of patients with AIMF. METHODS: We conducted a single-institution, retrospective chart review of patients diagnosed with AIMF to investigate clinical presentations, therapies, and outcomes. RESULTS: Twelve patients with AIMF were identified with a mean follow-up of 5.8 years. All patients had detectable autoantibodies and the majority had concomitant autoimmune disorders. Four patients experienced a complete response of cytopenias and 3 patients experienced a partial response (PR) of cytopenias with immunosuppressive therapy. One patient achieved a PR following splenectomy. No patients were diagnosed with myeloproliferative neoplasms during the follow-up period. CONCLUSIONS: AIMF contributes to cytopenias in the subset of patients with various autoimmune disorders. The majority of patients with AIMF experience an improvement in cytopenias with immunosuppressive therapy.

Pegylated interferon for the treatment of early myelofibrosis: correlation of serial laboratory studies with response to therapy.

Pegylated interferon α-2a (Peg-IFN) has been shown to induce hematologic and molecular responses in patients with the Philadelphia-negative myeloproliferative neoplasms (MPNs), including polycythemia vera (PV) and essential thrombocythemia (ET). We describe a series of patients with long-standing MPNs among whom Peg-IFN was initiated when they developed anemia and increased bone marrow reticulin fibrosis suggestive of early transformation to post-ET (PET) or post-PV (PPV) myelofibrosis (MF). Six patients were treated with Peg-IFN for a mean duration of 33.8 months (range 2-63 months). Five patients had long-standing ET (three were calreticulin (CALR)-positive, one janus kinase 2 (JAK2)-positive, and one JAK2-negative and CALR-negative), and one had long-standing JAK2-positive PV prior to starting Peg-IFN. This is the first study to report that, concurrent with the improvement in anemia, serial laboratory studies demonstrate an increase in serum LDH and left-shifted myeloid cells in the peripheral circulation over approximately 6 months, followed by a gradual normalization of these findings. Splenomegaly also increased and then resolved among responding patients. Serial bone marrow biopsies were available, which showed little change except for improvement in the grade of reticulin fibrosis in two patients. Among patients with early transformation to PET or PPV MF, our data support the efficacy of Peg-IFN in improving hemoglobin levels and reducing splenomegaly. These peripheral blood findings should not, therefore, be considered evidence of treatment failure within the first year of Peg-IFN therapy.