NCCN Guidelines® Insights: Systemic Mastocytosis, Version 3.2024.

Mastocytosis is a heterogeneous group of disorders comprising cutaneous mastocytosis, systemic mastocytosis, and mast cell sarcoma. It is associated with a variety of symptoms related to the release of mast cell mediators and mast cell tissue infiltration. Referral to specialized centers with expertise in the management of mastocytosis and multidisciplinary collaboration with subspecialists (eg, allergists for the management of anaphylaxis and drug hypersensitivities, anesthesiologists for invasive procedures or surgery, high-risk obstetrician for pregnancy) is recommended. The NCCN Guidelines for Systemic Mastocytosis provide evidence- and consensus-based recommendations for the diagnosis and comprehensive care of patients with systemic mastocytosis. The multidisciplinary panel of experts convenes at least once a year to review requested changes to the guidelines from both internal and external entities as well as to discuss data on existing and new therapies. These NCCN Guidelines Insights focus on some of the recent updates to the guidelines.

Psychological mobile app for patients with acute myeloid leukemia: A pilot randomized clinical trial.

BACKGROUND: Patients with acute myeloid leukemia (AML) experience a substantial decline in quality of life (QoL) and mood during their hospitalization for intensive chemotherapy, yet few interventions have been developed to enhance patient-reported outcomes during treatment. METHODS: We conducted a pilot randomized trial (ClinicalTrials.gov identifier NCT03372291) of DREAMLAND, a psychological mobile application for patients with a new diagnosis of AML who are receiving intensive chemotherapy. Patients were randomly assigned to DREAMLAND or usual care. DREAMLAND included four required modules focused on: (1) supportive psychotherapy to help patients deal with the initial shock of diagnosis, (2) psychoeducation to manage illness expectations, (3) psychosocial skill-building to promote effective coping, and (4) self-care. The primary end point was feasibility, which was defined as ≥60% of eligible patients enrolling and 60% of those enrolled completing ≥60% of the required modules. We assessed patient QoL (the Functional Assessment of Cancer Therapy-Leukemia), psychological distress (the Hospital Anxiety and Depression Scale and the Patient Health Questionnaire-9), symptom burden (the Edmonton Symptom Assessment Scale), and self-efficacy (the Cancer Self-Efficacy Scale) at baseline and at day 20 after postchemotherapy. RESULTS: We enrolled 60 of 90 eligible patients (66.7%), and 62.1% completed ≥75% of the intervention modules. At day 20 after chemotherapy, patients who were randomized to DREAMLAND reported improved QoL scores (132.06 vs. 110.72; p =.001), lower anxiety symptoms (3.54 vs. 5.64; p = .010) and depression symptoms (Hospital Anxiety and Depression Scale: 4.76 vs. 6.29; p = .121; Patient Health Questionnaire-9: 4.62 vs. 8.35; p < .001), and improved symptom burden (24.89 vs. 40.60; p = .007) and self-efficacy (151.84 vs. 135.43; p = .004) compared with the usual care group. CONCLUSIONS: A psychological mobile application for patients with newly diagnosed AML is feasible to integrate during hospitalization for intensive chemotherapy and may improve QoL, mood, symptom burden, and self-efficacy.

Impact of Allocation on Survival During Intermittent Chemotherapy Shortages: A Modeling Analysis.

BACKGROUND: Intermittent shortages of chemotherapeutics used to treat curable malignancies are a worldwide problem that increases patient mortality. Although multiple strategies have been proposed for managing these shortages (eg, prioritizing patients by age, scarce treatment efficacy per volume, alternative treatment efficacy difference), critical clinical dilemmas arise when selecting a management strategy and understanding its impact. PATIENTS AND METHODS: We developed a model to compare the impact of different allocation strategies on overall survival during intermittent chemotherapy shortages and tested it using vincristine, which was recently scarce for 9 months in the United States. Demographic and treatment data were abstracted from 1,689 previously treated patients in our tertiary-care system; alternatives were abstracted from NCCN Clinical Practice Guidelines in Oncology for each disease and survival probabilities from the studies cited therein. Modeled survival was validated using SEER data. Nine-month shortages were modeled for all possible supply levels. Pairwise differences in 3-year survival and risk reductions were calculated for each strategy compared with standard practice (first-come, first-served) for each 50-mg supply increment, as were supply thresholds above which each strategy maintained survival similar to scenarios without shortages. RESULTS: A strategy prioritizing by higher vincristine efficacy per volume and greater alternative treatment efficacy difference performed best, improving survival significantly (P<.01) across 86.5% of possible shortages (relative risk reduction, 8.3%; 99% CI, 8.0-8.5) compared with standard practice. This strategy also maintained survival rates similar to a model without shortages until supply fell below 72.2% of the amount required to treat all patients, compared with 94.3% for standard practice. CONCLUSIONS: During modeled vincristine shortages, prioritizing patients by higher efficacy per volume and alternative treatment efficacy difference significantly improved survival over standard practice. This approach can help optimize allocation as intermittent chemotherapy shortages continue to arise.

NCCN Guidelines® Insights: Hematopoietic Growth Factors, Version 1.2022.

The NCCN Guidelines for Hematopoietic Growth Factors provide recommendations for the appropriate use of growth factors in the clinical management of febrile neutropenia (FN), chemotherapy-induced thrombocytopenia (CIT), and chemotherapy-induced anemia (CIA). Management and prevention of these sequelae are an integral part of supportive care for many patients undergoing cancer treatment. The purpose of these guidelines is to operationalize the evaluation, prevention, and treatment of FN, CIT, and CIA in adult patients with nonmyeloid malignancies and to enable the patient and clinician to assess management options for FN, CIT, and CIA in the context of an individual patient's condition. These NCCN Guidelines Insights provide a summary of the important recent updates to the NCCN Guidelines for Hematopoietic Growth Factors, with particular emphasis on the incorporation of a newly developed section on CIT.

Myeloproliferative Neoplasms, Version 3.2022, NCCN Clinical Practice Guidelines in Oncology.

The classic Philadelphia chromosome-negative myeloproliferative neoplasms (MPN) consist of myelofibrosis, polycythemia vera, and essential thrombocythemia and are a heterogeneous group of clonal blood disorders characterized by an overproduction of blood cells. The NCCN Clinical Practice Guidelines in Oncology (NCCN Guidelines) for MPN were developed as a result of meetings convened by a multidisciplinary panel with expertise in MPN, with the goal of providing recommendations for the management of MPN in adults. The Guidelines include recommendations for the diagnostic workup, risk stratification, treatment, and supportive care strategies for the management of myelofibrosis, polycythemia vera, and essential thrombocythemia. Assessment of symptoms at baseline and monitoring of symptom status during the course of treatment is recommended for all patients. This article focuses on the recommendations as outlined in the NCCN Guidelines for the diagnosis of MPN and the risk stratification, management, and supportive care relevant to MF.

Sequencing of novel agents in relapsed/refractory B-cell acute lymphoblastic leukemia: Blinatumomab and inotuzumab ozogamicin may have comparable efficacy as first or second novel agent therapy in relapsed/refractory acute lymphoblastic leukemia.

BACKGROUND: The availability of novel agents (NAs), including blinatumomab and inotuzumab ozogamicin (InO), has improved the outcomes of patients with relapsed/refractory (RR) B-cell acute lymphoblastic leukemia (ALL). Because of the relative effectiveness, it is often a challenge for clinicians to determine how to best sequence these NAs with respect to efficacy and toxicity. METHODS: In this multicenter, retrospective study of patients with RR ALL treated with blinatumomab, InO, or both, their efficacy as a first or second NA was compared. RESULTS: Among 276 patients, 221 and 55 received blinatumomab and InO, respectively, as a first NA therapy. The complete remission (CR)/complete remission with incomplete count recovery (CRi) rate was 65% and 67% for the blinatumomab and InO groups, respectively (P = .73). The rate of treatment discontinuation due to adverse events was 4% and 7% in the blinatumomab and InO groups, respectively. Ninety-two patients (43%) in the blinatumomab group and 13 patients (29%) in the InO group proceeded with allogeneic hematopoietic stem cell transplantation. The median overall survival (OS) was 15 and 11.6 months in the blinatumomab and InO groups, respectively. A subset analysis was performed for 61 patients who received both NAs (blinatumomab and then InO [n = 40] or InO and then blinatumomab [n = 21]). The CR/CRi rate was 58% for patients who received InO as the second NA and 52% for patients who received blinatumomab as the second NA. The median OS was 10.5 for patients who received InO as the second NA and 5.9 months for patients who received blinatumomab as the second NA (P = .09). CONCLUSIONS: Although the limited power of this study to detect a significant difference between subgroups is acknowledged, the data suggest that blinatumomab and InO may have comparable efficacy as a first or second NA therapy in RR ALL.

Impact of Cancer History on Outcomes Among Hospitalized Patients with COVID-19.

BACKGROUND: Early reports suggested increased mortality from COVID-19 in patients with cancer but lacked rigorous comparisons to patients without cancer. We investigated whether a current cancer diagnosis or cancer history is an independent risk factor for death in hospitalized patients with COVID-19. PATIENTS AND METHODS: We identified patients with a history of cancer admitted to two large hospitals between March 13, 2020, and May 10, 2020, with laboratory-confirmed COVID-19 and matched them 1:2 to patients without a history of cancer. RESULTS: Men made up 56.2% of the population, with a median age of 69 years (range, 30-96). The median time since cancer diagnosis was 35.6 months (range, 0.39-435); 80% had a solid tumor, and 20% had a hematologic malignancy. Among patients with cancer, 27.8% died or entered hospice versus 25.6% among patients without cancer. In multivariable analyses, the odds of death/hospice were similar (odds ratio [OR], 1.09; 95% confidence interval [CI], 0.65-1.82). The odds of intubation (OR, 0.46; 95% CI, 0.28-0.78), shock (OR, 0.54; 95% CI, 0.32-0.91), and intensive care unit admission (OR, 0.51; 95% CI, 0.32-0.81) were lower for patients with a history of cancer versus controls. Patients with active cancer or who had received cancer-directed therapy in the past 6 months had similar odds of death/hospice compared with cancer survivors (univariable OR, 1.31; 95% CI, 0.66-2.60; multivariable OR, 1.47; 95% CI, 0.69-3.16). CONCLUSION: Patients with a history of cancer hospitalized for COVID-19 had similar mortality to matched hospitalized patients with COVID-19 without cancer, and a lower risk of complications. In this population, patients with active cancer or recent cancer treatment had a similar risk for adverse outcomes compared with survivors of cancer. IMPLICATIONS FOR PRACTICE: This study investigated whether a current cancer diagnosis or cancer history is an independent risk factor for death or hospice admission in hospitalized patients with COVID-19. Active cancer, systemic cancer therapy, and a cancer history are not independent risk factors for death from COVID-19 among hospitalized patients, and hospitalized patients without cancer are more likely to have severe COVID-19. These findings provide reassurance to survivors of cancer and patients with cancer as to their relative risk of severe COVID-19, may encourage oncologists to provide standard anticancer therapy in patients at risk of COVID-19, and guide triage in future waves of infection.

High NPM1-mutant allele burden at diagnosis predicts unfavorable outcomes in de novo AML.

Acute myeloid leukemia (AML) with mutated NPM1 is a newly recognized separate entity in the revised 2016 World Health Organization classification and is associated with a favorable prognosis. Although previous studies have evaluated NPM1 in a binary fashion, little is known about the significance of its mutant allele burden at diagnosis, nor has the effect of comutations (other than FLT3) been extensively evaluated. We retrospectively used targeted sequencing data from 109 patients with de novo AML with mutated NPM1 to evaluate the potential significance of NPM1 variant allele frequency (VAF), comutations, and clinical parameters with regard to patient outcomes. We observed that high NPM1 VAF (uppermost quartile) correlated with shortened overall survival (median, 12.1 months vs not reached; P < .0001) as well as event-free survival (median, 7.5 vs 65.44 months; P < .0001) compared with the other NPM1-mutated cases. In both univariate and multivariable analyses, high NPM1 VAF had a particularly adverse prognostic effect in the subset of patients treated with stem-cell transplantation in first remission (P = .0004) and in patients with mutated DNMT3A (P < .0001). Our findings indicate that the prognostic effect of NPM1 mutation in de novo AML may be influenced by the relative abundance of the mutated allele.

Considerations for Use of Hematopoietic Growth Factors in Patients With Cancer Related to the COVID-19 Pandemic.

Hematopoietic growth factors, including erythrocyte stimulating agents (ESAs), granulocyte colony-stimulating factors, and thrombopoietin mimetics, can mitigate anemia, neutropenia, and thrombocytopenia resulting from chemotherapy for the treatment of cancer. In the context of pandemic SARS-CoV-2 infection, patients with cancer have been identified as a group at high risk of morbidity and mortality from this infection. Our subcommittee of the NCCN Hematopoietic Growth Factors Panel convened a voluntary group to review the potential value of expanded use of such growth factors in the current high-risk environment. Although recommendations are available on the NCCN website in the COVID-19 Resources Section (https://www.nccn.org/covid-19/), these suggestions are provided without substantial context or reference. Herein we review the rationale and data underlying the suggested alterations to the use of hematopoietic growth factors for patients with cancer in the COVID-19 era.

NCCN Guidelines Insights: Hematopoietic Growth Factors, Version 1.2020.

Management of febrile neutropenia (FN) is an integral part of supportive care for patients undergoing cancer treatment. The NCCN Guidelines for Hematopoietic Growth Factors provide suggestions for appropriate evaluation, risk determination, prophylaxis, and management of FN. These NCCN Guidelines are intended to guide clinicians in the appropriate use of growth factors for select patients undergoing treatment of nonmyeloid malignancies. These NCCN Guidelines Insights highlight important updates to the NCCN Guidelines regarding the incorporation of newly FDA-approved granulocyte-colony stimulating factor biosimilars for the prevention and treatment of FN.

Myeloid/Lymphoid Neoplasms with Eosinophilia and TK Fusion Genes, Version 3.2021, NCCN Clinical Practice Guidelines in Oncology.

Eosinophilic disorders and related syndromes represent a heterogeneous group of neoplastic and nonneoplastic conditions, characterized by more eosinophils in the peripheral blood, and may involve eosinophil-induced organ damage. In the WHO classification of myeloid and lymphoid neoplasms, eosinophilic disorders characterized by dysregulated tyrosine kinase (TK) fusion genes are recognized as a new category termed, myeloid/lymphoid neoplasms with eosinophilia and rearrangement of PDGFRA, PDGFRB or FGFR1 or with PCM1-JAK2. In addition to these aforementioned TK fusion genes, rearrangements involving FLT3 and ABL1 genes have also been described. These new NCCN Guidelines include recommendations for the diagnosis, staging, and treatment of any one of the myeloid/lymphoid neoplasms with eosinophilia (MLN-Eo) and a TK fusion gene included in the 2017 WHO Classification, as well as MLN-Eo and a FLT3 or ABL1 rearrangement.

Outcomes for older adults with acute myeloid leukemia after an intensive care unit admission.

BACKGROUND: Older adults with acute myeloid leukemia (AML) are often assumed to have poor outcomes after admission to the intensive care unit (ICU). However, little is known about ICU utilization and post-ICU outcomes in this population. METHODS: The authors conducted a retrospective analysis for 330 patients who were 60 years old or older and were diagnosed with AML between 2005 and 2013 at 2 hospitals in Boston.They used descriptive statistics to examine the proportion of patients admitted to the ICU as well as their mortality and functional recovery. They used logistic regression to identify risk factors for in-hospital mortality. RESULTS: Ninety-six patients (29%) were admitted to the ICU, primarily because of respiratory failure (39%), septic shock (28%), and neurological compromise (9%). The proportions of patients who survived to hospital discharge, 90 days, and 1 year were 47% (45 of 96), 35% (34 of 96), and 30% (29 of 96), respectively. At 90 days, 76% of the patients had an Eastern Cooperative Oncology Group performance status (ECOG PS) of 0 or 1, and 86% were in complete remission (CR) and/or continued to receive AML-directed therapy. In a multivariate analysis, a poorer baseline ECOG PS score (odds ratio, 2.76; P = .013) and the need for 2 or more life-sustaining therapies (ie, vasopressors, invasive ventilation, and/or renal replacement therapy; odds ratio, 12.4; P < .001) were associated with increased odds of in-hospital mortality. CONCLUSIONS: Although almost one-third of older patients with AML are admitted to an ICU, nearly half survive to hospital discharge with good functional outcomes. The baseline performance status and the need for 2 or more life-sustaining therapies predict hospital mortality. These data support the judicious use of ICU resources for older patients with AML.

Patient-Clinician Discordance in Perceptions of Treatment Risks and Benefits in Older Patients with Acute Myeloid Leukemia.

BACKGROUND: Older patients (≥60 years) with acute myeloid leukemia (AML) face difficult decisions regarding treatment with "intensive" chemotherapy that carries significant toxicity for a small chance of a cure versus "nonintensive" chemotherapy to control the disease, but with fewer side effects. However, studies of how these patients understand the risks and benefits of such treatments are lacking. METHODS: We conducted a longitudinal study of older patients newly diagnosed with AML assessing patients' (n = 100) and oncologists' (n = 11) perceptions of treatment-related mortality at enrollment and prognosis at 1 month. We examined concordance between patients' and oncologists' perceptions using Cohen's kappa (κ < 0.10 indicates little/no concordance). RESULTS: We enrolled patients within 72 hours of initiating intensive (n = 50) or nonintensive (n = 50) chemotherapy. Whereas 91% of patients reported that they were "somewhat" to "extremely likely" to die from treatment, oncologists estimated that only 12% were at high risk of dying because of treatment (κ = -0.09). Ninety percent of patients reported that they were "somewhat" or "very likely" to be cured of their AML, whereas oncologists estimated this chance of cure for only 31% of patients (κ = 0.05). Among patients receiving intensive chemotherapy, 98% reported that they were "somewhat" or "very likely" to be cured, whereas their oncologists estimated this likelihood of cure for only 49% (κ = 0.04); among those receiving nonintensive chemotherapy and their clinicians, these proportions were 82% and 13%, respectively (κ = 0.03). Patients who indicated a lower likelihood of cure reported significantly higher depression symptoms (p = .03). CONCLUSION: Older patients with AML overestimate the risks and benefits of treatment. Interventions to facilitate communication and enhance patients' understanding of the goals of therapy and treatment risk are needed. IMPLICATIONS FOR PRACTICE: Older patients with acute myeloid leukemia (AML) are confronted with challenging decisions regarding treatment with "intensive" chemotherapy that carries significant toxicity for a small chance of a cure versus "nonintensive" chemotherapy to control the disease, but with fewer side effects. A clear understanding of the likely outcome and risks of the various treatment strategies is essential for these patients to make informed decisions about their care. This article reports that older patients with AML overestimate both the risks and benefits of treatment and have substantial misperceptions about their prognosis. Interventions to enhance patients' understanding of their prognosis and treatment risk are needed.

Design and rationale for the life after stopping tyrosine kinase inhibitors (LAST) study, a prospective, single-group longitudinal study in patients with chronic myeloid leukemia.

BACKGROUND: Treatment of chronic myeloid leukemia with a tyrosine kinase inhibitor (TKI) offers significant improvements over previous treatments in terms of survival and toxicity yet nevertheless is associated with reduced health-related quality of life and very high cost. Several small studies from Europe and Australia suggested that discontinuing TKIs with regular monitoring was safe. METHODS: The Life After Stopping TKIs (LAST) study is a large, U.S.-based study that aims to improve the evidence for clinical decision making regarding TKI discontinuation with monitoring in patients with chronic myeloid leukemia who have a deep molecular response to TKI therapy. The LAST study is a non-randomized, prospective, single-group longitudinal study of 173 patients. The co-primary objectives are to determine the proportion of patients who develop molecular recurrence (> 0.1% BCR-ABLIS) after discontinuing one of four TKIs (imatinib, dasatinib, nilotinib, or bosutinib) and to compare the patient-reported health status of patients before and after stopping TKIs. Outcomes are assessed at baseline and throughout the 36-month study follow-up period with a central laboratory used for blood samples. All samples with undetectable BCR-ABL are also examined using digital polymerase chain reaction, which is a more sensitive nanofluidic polymerase chain reaction system. DISCUSSION: Because of their high cost and side effects, discontinuation of TKIs for patients with chronic myeloid leukemia who have a deep molecular response to TKI therapy is a promising approach to treatment. The LAST study is the largest U.S.-based TKI discontinuation study. It is the first to allow participation from patients on any of 4 first- and second-generation TKIs, includes a robust approach to measurement of clinical and patient-reported outcomes, and is using digital polymerase chain reaction to explore better prediction of safe discontinuation. TRIAL REGISTRATION: This study was registered prospectively on October 21, 2014 and assigned trial number NCT02269267 .

Systemic Mastocytosis, Version 2.2019, NCCN Clinical Practice Guidelines in Oncology.

Mastocytosis is a group of heterogeneous disorders resulting from the clonal proliferation of abnormal mast cells and their accumulation in the skin and/or in various extracutaneous organs. Systemic mastocytosis is the most common form of mastocytosis diagnosed in adults, characterized by mast cell infiltration of one or more extracutaneous organs (with or without skin involvement). The identification of KIT D816V mutation and the emergence of novel targeted therapies have significantly improved the diagnosis and treatment of systemic mastocytosis. However, certain aspects of clinical care, particularly the diagnosis, assessment, and management of mediator-related symptoms continue to present challenges. This manuscript discusses the recommendations outlined in the NCCN Guidelines for the diagnosis and management of patients with systemic mastocytosis.

A phase I study of lenalidomide plus chemotherapy with mitoxantrone, etoposide, and cytarabine for the reinduction of patients with acute myeloid leukemia.

Patients with relapsed AML have a poor prognosis and limited responses to standard chemotherapy. Lenalidomide is an immunomodulatory drug that may modulate anti-tumor immunity. We performed a study to evaluate the safety and tolerability of lenalidomide with mitoxantrone, etoposide and cytarabine (MEC) in relapsed/refractory AML. Adult patients with relapsed/refractory AML were eligible for this phase I dose-escalation study. We enrolled 35 patients using a "3 + 3" design, with a 10 patient expansion cohort at the maximum tolerated dose (MTD). Lenalidomide was initially given days 1-14 and MEC days 4-8; due to delayed count recovery, the protocol was amended to administer lenalidomide days 1-10. The dose of lenalidomide was then escalated starting at 5 mg/d (5-10-25-50). The primary objective was tolerability and MTD determination, with secondary outcomes including overall survival (OS). The MTD of lenalidomide combined with MEC was 50 mg/d days 1-10. Among the 35 enrolled patients, 12 achieved complete remission (CR) (34%, 90%CI 21-50%); 30-day mortality was 6% and 60-day mortality 13%. The median OS for all patients was 11.5 months. Among 17 patients treated at the MTD, 7 attained CR (41%); the median OS was not reached while 12-month OS was 61%. Following therapy with MEC and lenalidomide, patient CD4+ and CD8+ T-cells demonstrated increased inflammatory responses to autologous tumor lysate. The combination of MEC and lenalidomide is tolerable with an RP2D of lenalidomide 50 mg/d days 1-10, yielding encouraging response rates. Further studies are planned to explore the potential immunomodulatory effect of lenalidomide and MEC.

Self-reported sleep disturbance and survival in myelodysplastic syndromes.

Neither the prevalence of sleep disturbance nor its association with fatigue and overall survival (OS) are well understood for patients with myelodysplastic syndromes (MDS). New patients at our institution (n = 251; 2006-2014) completed the European Organization for Research and Treatment of Cancer Quality of Life Questionnaire, which includes questions about sleep and fatigue. Fifty-three per cent reported at least 'a little' trouble sleeping. In multivariable models, anaemia and sleep disturbance were associated with fatigue (both P < 0·001). Additionally, in separate models, sleep disturbance (P = 0·002) and fatigue (P = 0·04) both predicted OS. Our data suggest that improving sleep quality may impact MDS-related fatigue and OS.

Results of a phase 2 study of pacritinib (SB1518), a JAK2/JAK2(V617F) inhibitor, in patients with myelofibrosis.

Pacritinib (SB1518) is a Janus kinase 2 (JAK2), JAK2(V617F), and Fms-like tyrosine kinase 3 inhibitor that does not inhibit JAK1. It demonstrated a favorable safety profile with promising efficacy in phase 1 studies in patients with primary and secondary myelofibrosis (MF). This multicenter phase 2 study further characterized the safety and efficacy of pacritinib in the treatment of patients with MF. Eligible patients had clinical splenomegaly poorly controlled with standard therapies or were newly diagnosed with intermediate- or high-risk Lille score. Patients with any degree of cytopenia were eligible. Thirty-five patients were enrolled. At entry, 40% had hemoglobin <10 g/dL and 43% had platelets <100 000× 10(9)/L. Up to week 24, 8 of 26 evaluable patients (31%) achieved a ≥35% decrease in spleen volume determined by magnetic resonance imaging and 14 of 33 (42%) attained a ≥50% reduction in spleen size by physical examination. Median MF symptom improvement was ≥50% for all symptoms except fatigue. Grade 1 or 2 diarrhea (69%) and nausea (49%) were the most common treatment-emergent adverse events. The study drug was discontinued in 9 patients (26%) due to adverse events (4 severe). Pacritinib is an active agent in patients with MF, offering a potential treatment option for patients with preexisting anemia and thrombocytopenia. This trial was registered at www.clinicaltrials.gov as #NCT00745550.