Post Hoc Data Show Anemia Benefits, Reduced Transfusion Burden With Momelotinib in Myelofibrosis

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Author(s): Chris Ryan

Fact checked by: Ashling Wahner

A post hoc analysis of a single-arm, phase 2 study (NCT02515630) and the phase 3 SIMPLIFY-1 (NCT01969838), SIMPLIFY-2 (NCT02101268), and MOMENTUM (NCT04173494) studies showed that momelotinib (Ojjaara) was associated with anemia-related benefits in most patients and a reduction in transfusion burden vs comparator treatments in patients with JAK inhibitor–naive and –experienced myelofibrosis.1

Findings published in Clinical Lymphoma, Myeloma & Leukemia showed that more than 77% of patients treated with momelotinib across the 4 trials experienced a numerical reduction in red blood cell (RBC) transfusion requirements during treatment compared with baseline.

“This [post hoc analysis] demonstrates that across all 3 phase 3 trials of momelotinib in myelofibrosis to date, at least 75% of patients treated with momelotinib either maintained or experienced improved transfusion intensities vs baseline,” lead study author Claire Harrison, MD, FRCP, FRCPath, a professor of myeloproliferative neoplasm and clinical director of Guy’s and St Thomas’ NHS Foundation Trust in London, United Kingdom, and colleagues wrote in the publication. “These results provide evidence that underscores the consistent anemia benefits provided by momelotinib for the majority of patients.”

In September 2023, the FDA approved momelotinib for the treatment of adult patients with intermediate or high-risk myelofibrosis, including primary myelofibrosis or secondary myelofibrosis, and anemia.2 This regulatory decision was supported by data from MOMENTUM and a subgroup of patients with anemia treated during SIMPLIFY-1.

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Molecular Response to Therapy Linked With Event-Free Survival in PV

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May 23, 2025

Author(s): Jared Kaltwasser

Fact checked by: Rose McNulty

Molecular response to therapy appears to correlate with event-free survival in patients with early polycythemia vera (PV), according to a new analysis. The findings were published in a research letter in the journal HemaSphere.1

While clonal expansion of JAK2V617F-mutated hematopoietic stem cells is implicated in almost all cases of PV, the potential implications of molecular response to therapy (MR) as demonstrated by reduced frequency of the variant allele have been disputed, the authors explained.

The findings also show that ropeginterferon alfa-2b is an effective therapy for molecular response in early polycythemia vera. | Image credit: fotogurmespb.- stock.adobe.com

The question is difficult to study, they noted, since the early onset of PV is associated with nonspecific symptoms. However, the authors cited a 2023 study assessing ruxolitinib (Jakafi; Incyte) in patients with high-risk PV found molecular response was correlated with superior outcomes, including event-free survival (EFS).2

In the new report, researchers examined data from the phase 3 PROUD-PV study and its extension trial, CONTINUATION-PV, to see whether there was a meaningful relationship between MR and EFS in patients with early-stage PV.1

The PROUD-PV trial involved participants with low- or high-risk PV requiring cytoreduction who were treatment naive or who had been pretreated with hydroxyurea for less than 3 years without resistance or intolerance. Participants were randomized on a 1:1 basis to receive either ropeginterferon alfa-2b (Besremi; PharmaEssentia) or hydroxyurea for 12 months. In CONTINUATION-PV, participants remained in their same treatment arm, though control-arm patients were allowed to switch from hydroxyurea to any standard treatment.

The final analysis of CONTINUATION-PV included 95 participants in the ropeginterferon alfa-2b cohort and 74 in the hydroxyurea/best available therapy control group. The median treatment duration for the two study arms was 6.3 years and 6.0 years, respectively.

The authors found that patients in the ropeginterferon alfa-2b arm had a reduction of median JAK2V617F variant allele frequency from 37.3% at baseline to 8.5% at year 6, with 66.0% of patients achieving MR. Patients in that cohort spent a median cumulative proportion of time in MR of 66.7%.

Evolving Myelofibrosis Treatments Aims to Fill Unmet Needs

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May 21, 2025

Author(s): Ryan Scott

Fact checked by: Spencer Feldman

Myelofibrosis is a Philadelphia-negative myeloproliferative neoplasms (MPN) and can occur as de novo disease. Myelofibrosis creates varying degrees of fibrosis and can cause driver mutations such as JAK2, CALR or MPL in approximately 90% of patients. These mutations cause constant activation of the JAK-STAT pathway, which can lead to uncontrolled cell growth.

Other mutations that can occur, such as ASXL1, SRSF2, EZH2, IDH1/2 and U2AF1, may also affect how the disease develops and prognosis. Moreover, common symptoms of the disease include fatigue, night sweats, fever, bone pain, cachexia, pruritus, thrombosis, and bleeding. Although disease progression is the most common reason for death and occurs in approximately 20% of patients, many patients also face serious risks from other complications. These include heart problems, infections, or bleeding due to low blood counts.

To combat the unmet needs within the myelofibrosis treatment landscape, there have been a number of studies investigating novel treatments for JAK inhibitor-ineligible or relapsed/refractory patients. To further explore these investigations, and the current and future states of the treatment landscapes, investigators broke everything down in research published in the American Journal of Hematology.

Understanding the Present Landscape and Ongoing Studies

The discovery of genetic mutations, as well as the role of the JAK-STAT pathway in the treatment of MPNs has led to the development of oral KAK inhibitors. These drugs work by blocking overactive JAK signaling involved in disease progression and symptom burden.

One such drug being used is Rituxan (ruxolitinib), which is the first ever U.S. Food and Drug Administration (FDA)-approved JAK inhibitor for myelofibrosis, approved by the regulatory agency in 2011. The agent elicits effective for symptom relief and spleen size reduction in approximately 50% of patients who are treated with it.

Common side effects of Rituxan include anemia and low platelets; other non-blood-related side effects include fatigue, diarrhea and infections. Long-term use of the agent may also increase the risk of secondary cancers (like non-melanoma skin cancer) and round 40% to 50% of individuals discontinue the drug within three years due to side effects or lack of efficacy. However, stopping Rituxan is linked to new mutations and poorer outcomes.

Another agent used in the treatment of myelofibrosis is Inrebic (fedratinib), which was approved in 2019 by the FDA for both patients with newly diagnosed disease and those who are refractory and/or intolerant to Rituxan. This agent provides similar benefits to those seen with Rituxan, including reduction of spleen size and symptoms, but with frequent gastrointestinal side effects, like nausea, diarrhea and vomiting.

Notably, Inrebic carries a black box warning for risk of Wernicke’s encephalopathy, making monitoring essential. Additionally, treatment with the agent is less effective in patients who were on high-dose Rituxan prior to switching.

Vonjo (pacritinib) is another treatment which was approved in 2022 for patients with severe low platelet counts in the myelofibrosis treatment space. Unlike Rituxan and Inrebic, it can be used in high-risk patients with more advanced disease and cytopenias. In trials such as the PERSIST-1 and PERSIST-2 studies, Vonjo showed modest spleen and symptom response but improved transfusion independence.

Vonjo is currently being tested in the PACIFICA trial for patients with platelets less than 50 × 10⁹/L.

Finally, Ojjaara (momelotinib) is also being used in the treatment space for patients with this disease and was approved by the FDA in 2023. Ojjaara targets JAK1/2 and ALK2, with a unique effect on anemia. Trials, including the SIMPLIFY-1 and SIMPLIFY-2 studies, showed similar spleen responses to Rituxan but greater improvements in anemia and transfusion independence.

The MOMENTUM study confirmed Ojjaara’s improved both symptoms and anemia in symptomatic, anemic patients previously treated with a JAK inhibitor.

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Ruxolitinib Plus Siremadlin Yielded Superior Spleen Volume Reduction in Patients With Myelofibrosis

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May 20, 2025

Author(s): Alexandra Gerlach, Associate Editor

Data from the ADORE trial (NCT04097821) suggest combining ruxolitinib (Jakafi; Incyte Corp) with novel agents such as siremadlin (HDM201, Novartis), rineterkib (LTT462; Novartis), sabatolimab (MBG453; Novartis), crizanlizumab (Adakveo; Novartis), or NIS793 (Novartis) was superior to ruxolitinib monotherapy in patients with myelofibrosis (MF). The investigators reported improved spleen volume reductions (SVR), which were greatest in patients treated with ruxolitinib in combination with siremadlin.1

3D visualization of red blood cells | Image Credit: © Thipphaphone – stock.adobe.com

MF is a disease that falls under the umbrella of myeloproliferative neoplasms, which is a group of diseases characterized by the overproduction of red blood cells, white blood cells, or platelets in the bone marrow. In MF, there is an ongoing reduced production of red blood cells that leads to bone marrow fibrosis, extramedullary hematopoiesis, recurrent splenomegaly, and anemia. Other symptoms can include fatigue, nocturnal sweats, bone pain, enlarged spleen, and weight loss. can arise as a main disease (primary MF) or as a subsequent condition to essential thrombocythemia (post-ET MF) and polycythemia vera (post-PV MF). In some cases, MF can progress to acute myeloid leukemia.2

Janus kinase (JAK) inhibitors, such as ruxolitinib, are the standard of care for treatment and management of MF-related complications and have yielded significantly favorable outcomes; however, they are associated with various adverse effects (AEs). Ruxolitinib was initially approved in 2011 for first-line treatment of patients with intermediate- and high-risk MF, but the agent is known to be highly associated with increased risk of persistent or worsening anemia. Despite its widespread use, approximately 70% of patients discontinue treatment after about 5 years, with a third citing an inadequate reduction in spleen volume as a key reason.3,4

ADORE is a randomized, open-label, phase 1/2 open platform study evaluating the safety and efficacy of 5 novel agents with ruxolitinib in patients with MF. The trial utilized an innovative open platform design and enrolled 44 patients in part 1 of the trial who were treated with ruxolitinib in combination with 1 of 5 investigational agents: siremadlin, rineterkib, sabatolimab, crizanlizumab, or NIS793. The largest cohort (n = 23) received the combination of ruxolitinib (orally at a dosage of 5 mg) and siremadlin (orally at a dosage of 10, 20, or 40 mg).1,4

Among those patients, the most common AEs were gastrointestinal issues, such as nausea and diarrhea, and hematologic toxicities, including thrombocytopenia, anemia, and neutropenia. Based on safety and efficacy findings, once-daily 30 mg siremadlin taken orally on days 1 through 5 of a 28-day cycle was chosen as the recommended phase 2 dose.4

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Real-World Data Shows Favorable Efficacy and Safety With Busulfan for MPNs

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Andrea S. Blevins Primeau, PhD, MBA
Publish Date

Busulfan treatment of myeloproliferative neoplasms (MPNs) demonstrated high response rates and infrequent adverse events (AEs), according to a study of real-world data from hospitals in the United Kingdom.

“Given the lack of prospective studies on the use of busulphan, our study contributes valuable real-world data on the safety and efficacy of busulphan which clinicians should find useful in managing this challenging cohort,” the researchers wrote in their report.

In the retrospective study, researchers analyzed data from 115 patients with MPNs from 13 hospitals. The median age of the cohort was 78 years and 44% of patients were male. The majority of patients had a diagnosis of essential thrombocythemia (ET) at 67%, followed by 24% with polycythemia vera (PV), 5% with MPN not otherwise specified, and 4% with myelofibrosis. JAK2 and CALR mutations were present among 62% and 13% of patients, respectively.

There were 16% of patients with a history of malignancy, including 8% of nonmelanoma skin cancers, and 8% with cancers that included those of the breast, prostate, lung, low-grade lymphoma, and melanoma.

One previous line of therapy (LOT) had been received by 13% of patients, 63% had 2 LOTs, 19% had 3 LOTs, and 5% had 4 LOTs. The most common previous cytoreductive therapy was hydroxycarbamide (78%), followed by anagrelide (16%), pegylated interferon (8%), P32 (3%), and ruxolitinib (2%).

The dosing regimens of busulfan included repeated single doses (31%) with a median dose of 38 mg, 1- to 4-week courses (30%) with a median dose 3.5 mg, and continuous therapy lasting more than 4 weeks (35%) with a median dose of 2 mg.

Our study contributes valuable real-world data on the safety and efficacy of busulphan which clinicians should find useful in managing this challenging cohort.

The median time from busulfan initiation to last follow-up or death was 23 months. There were 14% of patients who were alive with acceptable blood count control without any other cytoreductive therapy.

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Engulfment Reduces Patient Quality of Life in MPNs

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Jonathan Goodman, MPhil
Publish Date

Engulfment is a major factor affecting patient quality of life (QoL) among individuals diagnosed with myeloproliferative neoplasms (MPNs), according to research published in the European Journal of Oncology Nursing.

Psychological guidance aiming to mitigate the feeling of being overwhelmed by disease — the notion of engulfment in clinical medicine — is essential for improving QoL, the authors noted.

Although it is recognized that MPNs can drastically and negatively affect patient QoL, there is little understanding of the ways this occurs. For this longitudinal study, researchers evaluated psychosocial adjustment to living with MPNs, including essential thrombocythemia (ET), polycythemia vera (PV), and myelofibrosis (MF), with a focus on 4 factors: problem-solving coping, self-management, illness identity, and resilience.

Overall, 338 patients were enrolled. The researchers evaluated measurements of the 4 key factors at baseline and 6 months thereafter using established questionnaires, including the EORTC-QLQ-C30 for QoL measurements.

At enrolment, the average age was 62.8 years, the time since diagnosis was 7.7 years, and 63.6% of patients were female sex; 38.2%, 45.3%, and 16.6% of patients had been diagnosed with ET, PV, and MF, respectively.

The findings of this study indicate that psychosocial adjustment is important for QoL in patients with MPN, especially when adjustment is not optimal.

Analysis of the collected data suggested that II-subscale engulfment most strongly and negatively affected patient QoL (beta, 0.37; P <.001); this variable remained significant after the inclusion of control variables in the model, though the signal was less pronounced (beta, 0.16; P < .05).

Moreover, baseline QoL (beta, 0.32, P <.001) a wait-and-see treatment option (beta, 0.11, P <.05), and symptom burden at the second timepoint (beta, 0.36, P < .001) were all predictive of QoL.

“The findings of this study indicate that psychosocial adjustment is important for QoL in patients with MPN, especially when adjustment is not optimal,” the study authors wrote in their report. “Furthermore, the impact of MPN symptoms on QoL should not be underestimated.”

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Defective neutrophil clearance in JAK2V617F myeloproliferative neoplasms drives myelofibrosis via immune checkpoint CD24

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May 15, 2025

Eman Khatib-Massalha, Christian Andrea Di Buduo, Agathe L Chédeville, Ya-Hsuan Ho,…Simón Méndez-Ferrer Corresponding Author
Myeloproliferative neoplasms (MPNs) are hematopoietic stem cell-driven malignancies marked by excessive myelopoiesis and high risk of myelofibrosis, which remains therapeutically challenging. Senescent neutrophils home daily to the bone marrow (BM) to be cleared by macrophages. This avoids their accumulation, which can increase the risk of chronic inflammation or oncogenesis. Neutrophils carrying the most common oncogenic MPN driver (JAK2V617F) are protected from apoptosis, which may prolong their lifespan and enhance their pro-inflammatory activity. On the other hand, abnormal interactions of neutrophils with megakaryocytes (“emperipolesis”) have been associated with BM fibrosis in disparate hematological disorders, including MPN and grey platelet syndrome; however, the underlying pathophysiology remains unclear. We investigated neutrophil homeostasis and cellular interactions in MPN. We found that senescent neutrophils evade homeostatic clearance and accumulate in JAK2V617F MPN, but not in MPN caused by the second most prevalent mutations affecting Calreticulin (CALR) gene. This is explained by GM-CSF-JAK2-STAT5-dependent upregulation of the “don’t-eat-me” signal CD24 in neutrophils. Mechanistically, JAK2V617F CD24hi neutrophils evade efferocytosis, invade megakaryocytes and increase active TGF-b. Collectively, JAK2V617F neutrophil-megakaryocyte interactions promote platelet production in a humanized bioreactor and myelofibrosis in mouse models. Notably, chronic antibody blockade or genetic loss of CD24 restores clearance of senescent neutrophils, reduces emperipolesis and active TGF-b. Consequently, CD24 blockade improves thrombocytosis and prevents myelofibrosis in MPN mice. Taken together, these findings reveals defective neutrophil clearance as a cause of pathogenic microenvironmental interactions of inflammatory neutrophils with megakaryocytes, associated with myelofibrosis in MPN. Our study postulate CD24 as a candidate innate immune checkpoint in MPN.

Interferon Lowers Myelofibrosis Risk in Young Patients With Polycythemia Vera, Essential Thrombocytopenia

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May 15, 2025

Author(s): Alexandra Gerlach, Associate Editor

Early treatment with interferon reduced secondary myelofibrosis (sMF) risk in adolescent and young adult (AYA) patients with polycythemia vera (PV) or essential thrombocytopenia (ET), according to study data published in Leukemia.1

Red blood cells | Image Credit: © fotogurmespb - stock.adobe.com

MF is an incurable, rare hematologic malignancy characterized by the overproduction of red blood cells. This causes bone marrow scarring, which leads to severe anemia—a key factor impacting overall survival (OS) for patients with MF. It can develop as a primary disease or secondary to ET and PV, as well as progress to acute myeloid leukemia in some cases. Although MF is primarily diagnosed in older adults, 20% of cases are in individuals under the age of 40.1,2

AYA patients with ET or PV face unique clinical challenges due to their longer life expectancy because of a lack of data on long-term outcomes and treatment strategies. Existing guidelines are specific to older populations, despite the unique clinical considerations in younger patients.1

“These patients are expected to live for several decades, and the accumulation of additional thrombotic risk factors (age, cardiovascular conditions, additional mutations) may progressively heighten this risk,” the authors wrote. “This highlights a substantial and emerging concern regarding thrombotic events in this younger demographic.”1

The study evaluates complication rates, including thrombosis and progression to sMF, and the impact of interferon (IFN) on outcomes in patients diagnosed before the age of 25. The primary outcomes of the study were thrombosis-free survival (TFS), myelofibrosis-free survival (MFS), and OS in the entire cohort and for ET and PV patients separately, and the impact of treatment on these outcomes. Secondary outcomes were identification of risk factors associated with thrombotic events and sMF.1

The study included a total of 348 patients, of whom 278 were diagnosed with ET and 70 with PV, with a median age at diagnosis of 20 years. The incidence of thrombotic events was about 1.9 per 100 patient-years, with elevated white blood cell count (≥ 11 × 109/L) and absence of splenomegaly at diagnosis identified as significant risk factors. However, cytoreductive therapy did not reduce thrombotic risk. The incidence of sMF was 0.7 per 100 patient-years, with CALR mutations and a history of thrombosis associated with higher risk.1

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The evolving landscape of epigenetic target molecules and therapies in myeloid cancers: focus on acute myeloid leukemia and myeloproliferative neoplasms

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Published May 15, 2025

Michael W. M. Kühn, Naveen Pemmaraju & Florian H. Heidel

Abstract

Research on myeloid neoplasms, a field that has been driving scientific advances in cancer for over 50 years, has yielded many discoveries that have fundamentally reshaped our understanding of cancer biology. These insights, often the product of leukemia research, have been instrumental in developing more mechanism-based treatments in the early 2000s [1]. Recognizing epigenetic dysregulation as a common disease mechanism in myeloid cancers has been groundbreaking regarding recent treatment developments that exploit chromatin-based oncogenic mechanisms. In the case of acute myeloid leukemia (AML), sequencing studies aimed at assessing the complement of genetic alterations demonstrated that more than 60% of AML cases harbored disease-driving mutations in epigenetic regulators. This high prevalence underscores the importance of epigenetic dysregulation in AML pathogenesis [2, 3]. Chromatin regulators commonly control disease-specific transcriptional programs, making them attractive therapeutic targets to manipulate neoplastic gene expression programs, particularly in myeloid neoplasms. Several drugs targeting epigenetic mechanisms and exploiting myeloid disease-specific dependencies have recently been approved for treating myeloid neoplasms. Many additional drugs are currently being investigated in clinical trials, and numerous new compound developments are being studied in preclinical studies. This manuscript will review (1) chromatin-based disease mechanisms, such as DNA methylation, chromatin regulatory complexes, and histone modifications, currently investigated for therapeutic exploitation in myeloid malignancies, and (2) therapeutic developments already approved or investigated for treating these diseases.

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Seiter Explores Time of Initiation and Alternate Dosing of Ruxolitinib in Myelofibrosis

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By Targeted Oncology Staff
Fact checked by Jonah Feldman

During a live event, Karen Seiter, MD, discussed the role of the JAK/STAT pathway in myeloproliferative neoplasms and the use of ruxolitinib to treat myelofibrosis.

Karen Seiter, MD

Karen Seiter, MD

Professor of Medicine
New York Medical College
Director of  the Adult Leukemia Service
Westchester Medical Center
Valhalla, NY

CASE SUMMARY

  • A 68-year-old woman presented to her physician with symptoms of mild fatigue.
  • Spleen was palpable 6 to 7 cm below the left costal margin
  • Past medical history: no known comorbidities
  • Next-generation sequencing testing: JAK2 V617F mutation
  • Karyotype: 46,XX
  • Bone marrow biopsy: megakaryocyte proliferation and atypia with evidence of reticulin fibrosis
  • Blood smear: leukoerythroblastosis
  • Diagnosis: primary myelofibrosis

Risk

  • Dynamic International Prognostic Scoring System: intermediate-1
  • Mutation-Enhanced International Prognostic Scoring System for Transplantation-Age Patients: intermediate risk

Laboratory Values

  • Red blood cell count: 3.40 ×106/μL
  • Hemoglobin level: 9.7 g/dL
  • Hematocrit: 32.3%
  • Mean corpuscular volume: 94 μm3
  • White blood cell count: 23,000/μL
  • Platelet count: 450,000/μL
  • Peripheral blood blasts: <1%

Peers & Perspectives in Oncology: What disease states are currently classified as myeloproliferative neoplasms (MPNs)?

Seiter: The latest classification is the 2022 World Health Organization [WHO] classification.1,2 As a clinician, when we have myeloproliferative diseases, we think of MPNs [as meaning the patient] has too much of something: The WBC count is too high but with maturing myeloid and not with a lot of blasts, or the hemoglobin [level] is too high, or the [platelet count is] too high. That would be potentially chronic myelocytic leukemia [CML], polycythemia vera [PV], essential thrombocytopenia [ET], and for primary myelofibrosis, the most common presentation would be somebody with either anemia, with abdominal distension or early satiety from splenomegaly. The WBC count could be high; it could be low; platelets could be high, or they could be low.

When we’re working up patients with MPN, the first step is always to make sure that they don’t have CML, because CML can look like myelofibrosis because CML can present with a high platelet count. The first step is always to [test for] the Philadelphia chromosome and perform BCR::ABL1 testing to make sure it’s not CML.

Most of these patients are going to have a bone marrow [biopsy] done. There’s always the debate about, if you have somebody with a hemoglobin level of 20 g/dL, where it looks pretty clear that they have PV, do you need a bone marrow [biopsy] in order to formally diagnose the patient? You do because that’s part of the diagnostic criteria. But sometimes, if you have a much older patient with frailty, you have to consider the goals of care. Sometimes, there may be cases of patients who don’t get the bone marrow biopsy done. The only time it would be reasonable is if the hemoglobin level is high; for anything else, there are so many other things that [it] could be that it’s important to do the bone marrow biopsy for a diagnosis.

Mastocytosis used to be [listed among the] MPNs, but [the WHO] made it its own classification. MPNs with eosinophilia are a separate category. Now we have the myelodysplastic syndrome [MDS]/MPN overlap; that’s a separate category. Then, we have MDS, secondary myeloid neoplasms, and acute myeloid leukemia.

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