How I treat myeloproliferative neoplasms in pregnancy.

ABSTRACT: Although myeloproliferative neoplasms (MPNs) are traditionally considered diseases of adults in their sixth or seventh decade, these conditions do occur in young patients; for example, for essential thrombocythemia, in particular, there is a second peak in women of reproductive age. Therefore, pregnancy is an uncommon but not rare occurrence and clinical challenge in some scenarios. Here, we discuss in detail our local approach to the management of pregnancy in patients with MPN while taking a case-based approach. We include relevant updates in the field and point to a future research strategy that should be internationally focused to obtain as much information in as short a time as possible.

How I Treat Low-risk Polycythemia Vera Patients who Require Cytoreduction.

Polycythemia vera (PV) was first described by Vaquez in 1892. This is a chronic hematological malignancy which affects both older and young patients. Perhaps due to lack of a curative treatment and the perceived toxicities of prior therapies our focus in the past was to intensify treatment only for patients at higher risk of thrombosis. Recent triggers to challenge this approach include: a recognition that low-risk PV is not "no-risk", our ability to better recognize patients who would benefit from more intensive therapy from the perspective of thrombosis, and data showing that some treatments may reduce risk of transformation to myelofibrosis. Furthermore, there is emergent evidence that molecular monitoring may identify an improvement in disease state translating to improved overall survival. Here we describe clinical situations that would trigger the use of cytoreductive treatment for low-risk PV patients as well as our approach to choosing a specific cytoreductive agent and how to effectively monitor treatment.

Identifying disease-modifying potential in myelofibrosis clinical trials.

The ultimate goal of bringing most new drugs to the clinic in hematological malignancy is to improve overall survival. However, the use of surrogate endpoints for overall survival is increasingly considered standard practice, since a well validated surrogate endpoint can accelerate the outcome assessment and facilitate better clinical trial design. Established examples include monitoring minimal residual disease in chronic myeloid leukemia and acute leukemia, and metabolic response assessment in lymphoma. However, what happens when a clinical trial endpoint that is not a good surrogate for disease-modifying potential becomes ingrained as an expected outcome, and new agents are expected or required to meet this endpoint to demonstrate "efficacy"? JAK inhibitors for myelofibrosis have a specific impact on reducing symptom burden and splenomegaly, but limited impact on the natural history of the disease. Since the introduction of ruxolitinib more than a decade ago there has been modest incremental success in clinical trials for myelofibrosis, but no major leap forward to alter the natural history of the disease. We argue that the clinical development of novel agents for myelofibrosis will be accelerated by moving away from using endpoints that are specifically tailored to measure the beneficial effects of JAK inhibitors. We propose that specific measures of relevant disease burden, such as reduction in mutation burden as determined by molecular endpoints, should replace established endpoints. Careful re-analysis of existing data and trials in progress is needed to identify the most useful surrogate endpoints for future MF trials and better serve patient interest.

Proposals for Revised International Working Group-European LeukemiaNet Criteria for Anemia Response in Myelofibrosis.

With emerging new drugs in myelofibrosis (MF), a robust and harmonized framework for defining the severity of anemia and response to treatment will enhance clinical investigation and facilitate inter-study comparisons. Accordingly, the lead authors on the 2013 edition of the International Working Group-European LeukemiaNet (IWG-ELN) response criteria in MF were summoned to revise their document with the intent to i) account for gender-specific differences in determining hemoglobin levels for eligibility criteria, ii) revise definition of transfusion-dependent anemia (TDA) based on current restrictive transfusion practices, and iii) provide a structurally simple and easy to apply response criteria that are sensitive enough to detect efficacy signals (minor response) and also account for major responses. The initial draft of the 2024 IWG-ELN proposed criteria was subsequently circulated around a wider group of international experts and their feedback incorporated. The proposed articles include new definitions for TDA (≥3 units in the 12 weeks prior to study enrollment) and hemoglobin thresholds for eligibility criteria (<10 g/dL for women and <11 g/dL for men). The revised document also provides separate (TDA vs. non-TDA) and graded (major vs. minor response) response criteria while preserving the requirement for a 12-week period of screening and observation on treatment.

Myelofibrosis: Current unmet needs, emerging treatments, and future perspectives.

The current standard-of-care for treatment of myelofibrosis (MF) comprises inhibitors of the Janus kinase (JAK)/signal transducers and activators (STAT) pathway; however, despite their ability to alleviate symptoms, they do not appear to modify underlying disease and have not demonstrated substantial survival benefit. Allogeneic-hematopoietic stem cell transplantation remains the only curative option for patients with MF but is limited to a subset of high-risk and fit patients. Early disease modification could positively affect disease trajectory for lower risk patients with MF as well as those with conditions that can precede MF, such as polycythemia vera and essential thrombocythemia. Here, the authors discuss critical unmet needs in the MF treatment paradigm, including: the need for safe, impactful therapies for lower risk patients, thus allowing intervention when success is most likely; better development of first-line therapies (likely highly novel or combination strategies) for intermediate-risk/higher risk patients; and approved drugs to manage cytopenia. Finally, a consensus definition of disease modification is needed that informs trial design, allowing the development of clinical end points that enable understanding of therapies and responses and that facilitate the development of therapies that work according to this definition. Through close collaboration between clinicians, patients, and the pharmaceutical industry, better efforts to define benefit and identify patients most likely to benefit from a particular combination or treatment strategy should enable the development of more effective and safe treatments to extend and improve quality of life for patients with MF.

Myeloproliferative neoplasms in the adolescent and young adult population: A comprehensive review of the literature.

Myeloproliferative neoplasms (MPN) are characterized by a clonal proliferation of myeloid lineage cells within the bone marrow. The classical BCR-ABL negative MPNs are comprised of polycythaemia vera, essential thrombocythaemia and primary myelofibrosis. Historically, the majority of MPNs are diagnosed in adults older than 60 years of age; however, in recent years, there has been recognition of MPNs in the adolescent and young adult (AYA) population. AYAs with MPN, typically defined as between the ages of 15 and 39 years old, may comprise up to 20% of patients diagnosed with MPN. They demonstrate unique patterns of driver mutations and thrombotic events and remain at risk for progression to more aggressive disease states. Given the likely long length of time they will live with their disease, there is a significant unmet need in identifying well-tolerated and effective treatment options for these patients, particularly with the advent of disease modification. In this review, we provide a comprehensive overview of the clinical features, disease course and management of AYA patients with MPN and, in doing so, highlight key characteristics that distinguish them from their older counterparts.

Clinical utility of investigations in triple-negative thrombocytosis: A real-world, multicentre evaluation of UK practice.

Diagnosis of essential thrombocythaemia (ET) is challenging in patients lacking JAK2/CALR/MPL mutations. In a retrospective evaluation of 320 patients with 'triple-negative thrombocytosis', we assessed utility of bone marrow histology (90.9% of patients) and myeloid gene panel (MGP, 55.6%). Supportive histology ('myeloproliferative neoplasm-definite/probable', 36.8%) was associated with higher platelet counts and varied between centres. 14.6% MGP revealed significant variants: 3.4% JAK2/CALR/MPL and 11.2% other myeloid genes. Final clinical diagnosis was strongly predicted by histology, not MGP. 23.7% received cytoreduction (17.6% under 60 years). Real-world 'triple-negative' ET diagnosis currently depends heavily on histology; we advocate caution in MGP-negative cases and that specific guidelines are needed.

Myeloproliferative neoplasms: young patients, current data and future considerations.

The Philadelphia-negative chronic myeloproliferative neoplasms (MPNs) are clonal hematopoietic stem cell disorders predominantly occurring in elderly, whereas in children and young adults are quite infrequent. Therefore, less is known about clinical presentation, genetic abnormalities, prognosis and best management strategies for this groups of patients. Currently, more cases of younger MPN patients are diagnosed. Nevertheless, diagnosis of MPNs, especially in childhood, may be difficult due to lower incidence of JAK2V617F and CALR mutations and differences in peripheral blood counts between adults and children. Challenges for younger MPN patients are longer life expectances, specific psychosocial need, fertility and pregnancy need and a long term therapy side effect (including second cancers). The most severe MPNs complication is transformation to secondary myelofibrosis (MF) or acute myeloid leukemia (AML). Optimal management of young MPNs remains a challenge as the classical risk scores fail in young MPNs. Moreover, the main objective of young MPNs therapy should be the disease outcome modification. Therefore, international collaborative work between pediatricians and "adult hematologists" is required to measure outcomes and generate protocol of management of young MPNs.

Meaningful Symptomatic Change in Patients With Myelofibrosis From the SIMPLIFY Studies.

OBJECTIVES: Patients with myelofibrosis develop symptoms due to bone marrow fibrosis, systemic inflammation, and/or organomegaly. Alleviating symptoms improves overall quality of life. Clinical trials have historically defined symptom response as a reduction of at least 50% in Total Symptom Score at week 24 compared with baseline. Whether 50% constitutes a meaningful benefit has not been established. This study determined the meaningful change threshold (MCT) for 2 momelotinib phase III trials, SIMPLIFY-1 and SIMPLIFY-2. METHODS: The absolute and percentage MCT was determined using anchor-based methods applied to the modified Myeloproliferative Neoplasm Symptom Assessment Form v2.0 and Patient Global Impression of Change. MCTs were applied retrospectively to determine responder rates. Generalized estimating equations estimated the treatment-related difference in likelihood of improvement. RESULTS: In SIMPLIFY-1, a Janus kinase inhibitor-naive population, the MCT was 8 points. In SIMPLIFY-2, a previously Janus kinase inhibitor-treated population, the MCT was 6 points. A 32% MCT was determined in both studies, showing that the historic 50% reduction threshold may be a conservative choice. In SIMPLIFY-1, a similar proportion of patients achieved responder status with 24 weeks of momelotinib or ruxolitinib therapy based on the absolute MCT (39% vs 41%, respectively). In SIMPLIFY-2, a significantly greater proportion of patients treated with momelotinib achieved responder states compared with best available therapy based on absolute and percent change MCTs. CONCLUSIONS: This study demonstrates that momelotinib provided clinically meaningful symptom benefit for patients with myelofibrosis and provides insight into the appropriateness of the symptom change threshold used in historical studies.

Erythrocytosis: Diagnosis and investigation.

An absolute erythrocytosis is present when the red cell mass is greater than 125% of the predicted. This is suspected when the hemoglobin or hematocrit is above the normal range. An erythrocytosis can be classified as primary or secondary and congenital or acquired. The commonest primary acquired disorder is polycythemia vera. The diagnostic criteria for PV have evolved over time and this is the main diagnosis managed in hematology clinics. There are a variety of rare congenital causes both primary and secondary. In particular in young patients and/or those with a family history a congenital cause is suspected. There remains a larger cohort with acquired erythrocytosis mainly with non-hematological pathology. In order to explore for a cause of erythrocytosis, measurement of the erythropoietin level is a first step. A low erythropoietin level indicates a primary cause and a normal or elevated level indicates a secondary etiology. Further investigation is then dictated by initial findings and includes mutational testing with PCR and NGS for those in whom a congenital cause is suspected. Following this possibly bone marrow biopsy, scans, and further investigation as indicated by history and initial findings. Investigation is directed toward the identification of those with a hematological disorder which would be best managed following guidelines in hematology clinics and referral elsewhere in those for whom there are non-hematological reasons for the elevated hemoglobin.

Pathways to MPN presentation and time-to-diagnosis: results from a cross-sectional study.

BACKGROUND: Early cancer recognition is key to improving patient outcomes. Diagnosis is often delayed in myeloproliferative neoplasm (MPN) patients, putting them at risk of thromboembolic events and other complications pre-diagnosis. A clear understanding of the barriers to presentation and diagnosis is required. AIMS: To explore barriers and factors influencing delayed presentation and diagnosis of MPNs. DESIGN & SETTING: A cross-sectional study of MPN patients within the United Kingdom and the Republic of Ireland. METHOD: An online cross-sectional survey of MPN patients. Symptoms and factors influencing patient and General Practitioner (GP) delay were examined. Adjusted odds ratios (aOR) were calculated to explore the relationship between these factors and patient/GP delay. RESULTS: Most (80.2%) of the 620 patients completing the survey reported symptomatic presentation. The most common symptoms associated with patient delay were pruritus (aOR 1.89, 95% CI 1.19-3.01), headaches (aOR 1.86, 95% CI 1.13-2.82) and concentration difficulties (aOR 1.75, 95% CI 1.12-2.76). Attributing symptoms to ageing (aOR 1.92, 95% CI 1.19-3.11) and not wanting to burden the GP (aOR 2.17, 95% CI 1.35-3.50) were significantly associated with patient delay. Those reporting >3 blood cancer warning signs were more likely to experience GP delay than those experiencing fewer (aOR 3.26, 95% CI 1.75-6.29), and lack of relational continuity of GP care was significantly associated with GP delay (aOR 3.41, 95% CI 1.65-7.28). CONCLUSION: Debunking misconceptions around ageing, encouraging timely communication with GPs and improving relational continuity of GP care could assist in reducing diagnostic delays, prevent potentially fatal disease complications and ultimately improve MPN patient outcomes.

Safety and efficacy of fedratinib in patients with myelofibrosis previously treated with ruxolitinib: primary analysis of FREEDOM trial.

The phase 3b FREEDOM trial (ClinicalTrials.gov: NCT03755518) evaluates efficacy/safety of fedratinib in intermediate- or high-risk myelofibrosis patients with platelet count ≥50 × 109/L, previously treated with ruxolitinib. The trial design included protocol specified strategies to mitigate the risk for gastrointestinal (GI) adverse events (AEs), thiamine supplementation, and encephalopathy surveillance. Due to COVID-19, accrual was cut short with 38 patients enrolled. In the efficacy evaluable population (n = 35), nine (25.7%; 95% confidence interval 12.5-43.3) patients achieved primary endpoint of ≥35% spleen volume reduction (SVR) at end of cycle (EOC) 6; and 22 (62.9%) patients showed best overall response of ≥35% SVR up to end of treatment. Sixteen (44.4%) patients showed ≥50% reduction in total symptom score at EOC6 (n = 36). Compared to previously reported JAKARTA-2 trial, rates of GI AEs were lower, and no patient developed encephalopathy. Overall, FREEDOM study showed clinically relevant spleen and symptom responses with fedratinib, and effective mitigation of GI AEs.

Momelotinib versus Continued Ruxolitinib or Best Available Therapy in JAK Inhibitor-Experienced Patients with Myelofibrosis and Anemia: Subgroup Analysis of SIMPLIFY-2.

INTRODUCTION: Some Janus kinase (JAK) inhibitors such as ruxolitinib and fedratinib do not address and may worsen anemia in patients with myelofibrosis. In these cases, the JAK inhibitor may be continued at a reduced dose in an effort to maintain splenic and symptom control, with supportive therapy and/or red blood cell (RBC) transfusions added to manage anemia. This post hoc descriptive analysis of the phase 3 SIMPLIFY-2 trial evaluated the relative benefits of this approach versus switching to the JAK1/JAK2/activin A receptor type 1 inhibitor momelotinib in patients for whom anemia management is a key consideration. METHODS: SIMPLIFY-2 was a randomized (2:1), open-label, phase 3 trial of momelotinib versus best available therapy (BAT; 88.5% continued ruxolitinib) in JAK inhibitor-experienced patients with myelofibrosis (n = 156). Patient subgroups (n = 105 each) were defined by either baseline (1) hemoglobin (Hb) of < 100 g/L or (2) non-transfusion independence (not meeting the criteria of no transfusions and no Hb of < 80 g/L for the previous 12 weeks); outcomes have been summarized descriptively. RESULTS: In both subgroups of interest, week 24 transfusion independence rates were higher with momelotinib versus BAT/ruxolitinib: baseline Hb of < 100 g/L, 22 (33.3%) versus 5 (12.8%); baseline non-transfusion independent, 25 (34.7%) versus 1 (3.0%). Mean Hb levels over time were also generally higher in both subgroups with momelotinib, despite median transfusion rates through week 24 with momelotinib being comparable to or lower than with BAT/ruxolitinib. Spleen and symptom response rates with momelotinib in these subgroups were comparable to the intent-to-treat population, while rates with BAT/ruxolitinib were lower. CONCLUSION: In patients with moderate-to-severe anemia and/or in need of RBC transfusions, outcomes were improved by switching to momelotinib rather than continuing ruxolitinib and using anemia supportive therapies. TRIAL REGISTRATION: ClinicalTrials.gov: NCT02101268.

Patients with the rare blood cancer myelofibrosis often experience symptoms such as tiredness, an increase in the size of their spleens (an organ involved in filtering the blood), and anemia (too few red blood cells). One type of treatment for myelofibrosis, called a Janus kinase (JAK) inhibitor, can help patients to feel better and reduce the size of their spleens, but some JAK inhibitors do not help with anemia and may make it worse. In those situations, patients may continue to take their JAK inhibitor but also receive another type of treatment, called an anemia supportive therapy, and may also receive red blood cell transfusions. This study compared 2 treatment approaches, continuing the JAK inhibitor ruxolitinib and adding an anemia supportive therapy and/or transfusions versus switching to another treatment called momelotinib, in 2 groups of patients from a clinical trial: (1) patients with levels of hemoglobin (a red blood cell protein) at the start of the trial that indicated that they had anemia, and (2) patients who were already receiving red blood cell transfusions at the start of the trial. In both groups, more patients did not need red blood cell transfusions anymore at week 24 with momelotinib, and their hemoglobin levels on average became higher over time. More patients also had improvements in spleen size and symptoms with momelotinib. Overall, outcomes were improved by switching to momelotinib rather than continuing ruxolitinib and using supportive therapies and/or red blood cell transfusions to treat anemia.

Inherited polygenic effects on common hematological traits influence clonal selection on JAK2V617F and the development of myeloproliferative neoplasms.

Myeloproliferative neoplasms (MPNs) are chronic cancers characterized by overproduction of mature blood cells. Their causative somatic mutations, for example, JAK2V617F, are common in the population, yet only a minority of carriers develop MPN. Here we show that the inherited polygenic loci that underlie common hematological traits influence JAK2V617F clonal expansion. We identify polygenic risk scores (PGSs) for monocyte count and plateletcrit as new risk factors for JAK2V617F positivity. PGSs for several hematological traits influenced the risk of different MPN subtypes, with low PGSs for two platelet traits also showing protective effects in JAK2V617F carriers, making them two to three times less likely to have essential thrombocythemia than carriers with high PGSs. We observed that extreme hematological PGSs may contribute to an MPN diagnosis in the absence of somatic driver mutations. Our study showcases how polygenic backgrounds underlying common hematological traits influence both clonal selection on somatic mutations and the subsequent phenotype of cancer.

Safety and efficacy of luspatercept for the treatment of anemia in patients with myelofibrosis.

The ACE-536-MF-001 trial enrolled patients with myelofibrosis (n = 95) into 4 cohorts: patients in cohorts 1 and 3A were non-transfusion dependent (NTD) and had anemia; patients in cohorts 2 and 3B were transfusion dependent (TD); patients in cohort 3A/3B had stable ruxolitinib treatment prior to and during the study. All patients received luspatercept (1.0-1.75 mg/kg, 21-day cycles). Treatment was extended if clinical benefit was observed at day 169. The primary endpoint was anemia response rate (NTD, ≥1.5 g/dL hemoglobin increase from baseline; TD, transfusion-independence) over any 12-week period during the primary treatment period (weeks 1-24). Overall, 14% of patients in cohorts 1 and 3A, 10% in cohort 2, and 26% in cohort 3B met the primary endpoint. In cohorts 1 and 3A (NTD), 27% and 50% of patients respectively had mean hemoglobin increase ≥1.5 g/dL from baseline. Among TD patients, ~50% had ≥50% reduction in transfusion burden. Reduction in total symptom score was observed in all cohorts, with the greatest response rate seen in cohort 3A. Overall, 94% of patients had ≥1 adverse event (AE); 47% had ≥1 treatment-related AE (TRAE; 11% grade ≥3), most frequently hypertension (18%), managed with medical intervention. One patient had a serious TRAE leading to luspatercept discontinuation. Nine patients died on treatment (unrelated to study drug). In most patients, ruxolitinib dose and spleen size remained stable. In patients with myelofibrosis, luspatercept improved anemia and transfusion burden across cohorts; the safety profile was consistent with previous studies. NCT03194542 clinicaltrials.gov.

Polycythemia Vera: Barriers to and Strategies for Optimal Management.

Polycythemia vera (PV) is a subtype of myeloproliferative neoplasms characterized by impaired quality of life and severe complications. Despite the increasingly in-depth knowledge of this condition, it necessitates a multifaceted management approach to mitigate symptoms and prevent thrombotic and hemorrhagic events, ensuring prolonged survival. The therapeutic landscape has been revolutionized in recent years, where venesection and hydroxycarbamide associated with antiplatelet therapy have a central role and are now accompanied by other drugs, such as interferon and Janus kinase inhibitors. Ongoing research and advancements in targeted therapies hold promise for further enhancing the therapeutic choice for PV management.