Real World Management of Cytopenias and Infections in Patients With Myelofibrosis Treated With Ruxolitinib

Liesl A. Butler, Cecily Forsyth, Claire Harrison, Andrew C. Perkins

ABSTRACT
Introduction: Ruxolitinib was the first JAK2 inhibitor approved for the treatment of primary and secondary myelofibrosis. It is
currently used worldwide as first-line therapy for advanced disease (intermediate-2 and high-risk) and is effective in polycythaemia
vera (PV) and essential thrombocythaemia (ET), but not funded for this indication in many countries. Ruxolitinib has proven
benefits with respect to symptom control, reduction in spleen size and prolongation of survival; however, it rarely induces a
substantial reduction in allele burden and never provides a cure. Moreover, there are frequently encountered adverse effects and
dosing issues that require careful management to optimise its therapeutic benefit.

Methods and Results: In this case-based review, we use seven informative common clinical scenarios to discuss appropriate
investigation and management of cytopenias and infection issues.

Conclusions: We make recommendations based on 15 years of experience in using ruxolitinib and other JAK inhibitors for the
treatment of myelofibrosis. We discuss when allogeneic haematopoietic stem cell transplantation (AHSCT) should be considered
and some of the currently available alternative JAK inhibitors and trial options when AHSCT is not an option.

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Emerging Therapies in Myelofibrosis Could Extend Beyond JAK Inhibitors

March 24, 2025

Author(s): Ashley Chan

Fact checked by: Ashling Wahner

The September 2023 FDA approval of momelotinib (Ojjaara) for the treatment of patients with primary and secondary myelofibrosis with anemia provided the treatment paradigm with its fourth FDA-approved JAK inhibitor, a class of drugs that has helped improve symptoms associated with myelofibrosis and decrease spleen size, according to Raajit Rampal, MD, PhD.

Additional classes of drugs, such as BET inhibitors and immunotherapy agents, are also currently under investigation in clinical trials and could become “game-changers” if effective, Rampal noted.

“The major [message is] that myelofibrosis is not a monolithic disease, and the selection of the treatment needs to be tailored to the underlying issues and challenges the patient is facing,” said Rampal in an interview with OncLive®.

In the interview, Rampal discussed currently available JAK inhibitors and their limitations, emerging treatments for myelofibrosis, tips for treatment selection, and his takeaways from the 6th Annual Miami Cancer Institute Global Summit on Immunotherapies for Hematologic Malignancies.

Rampal is a hematologist-oncologist, the director of the Center for Hematologic Malignancies, and the director of the Myeloproliferative Neoplasms Program at Memorial Sloan Kettering Cancer Center in New York, New York.

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Dr Bhat on the Influence of MPN Risk Stratification on Treatment Decision-Making

March 20, 2025

Author(s): Seema A. Bhat, MD

Fact checked by: Ashling Wahner, Courtney Flaherty

Seema A. Bhat, MD, a hematologist at The Ohio State University Comprehensive Cancer Center—James; as well as an assistant professor in the Department of Internal Medicine in the Division of Hematology at The Ohio State University, discusses the importance of risk stratification for navigating treatment selection for patients with myeloproliferative neoplasms (MPNs).

Stratifying patients with MPNs into appropriate risk groups is crucial for treatment decision-making, as patients’ individual risk factors strongly factor into selection, Bhat says. Typically, patients with low-risk disease will receive treatments directed at symptom management, whereas cytoreductive agents like hydroxyurea, as well as targeted therapies like JAK inhibitors, are considered for patients with high-risk disease, she explains. Furthermore, allogeneic stem cell transplantation may be a curative treatment option for patients with very high–risk MPNs, she notes.

The revised IPSET Thrombosis Score is used for essential thrombocythemia (ET) risk stratification. Patients are considered to have low-risk polycythemia vera (PV) if they are younger than 60 years of age and have no history of thrombosis; patients are considered to have high-risk PV if they are older than 60 years of age and/or have a thrombosis history.

Four JAK inhibitors are FDA approved for the treatment of patients with MPNs. Ruxolitinib (Jakafi) is indicated for adult patients with intermediate- or high-risk myelofibrosis, including primary myelofibrosis and secondary (post-PV or post-ET) myelofibrosis; as well as adult patients with PV who have had an inadequate response or are intolerant to hydroxyurea. Fedratinib (Inrebic) is approved for adult patients with intermediate-2 or high-risk primary or secondary myelofibrosis. Pacritinib (Vonjo) is indicated for use in adult patients with intermediate- or high-risk primary or secondary myelofibrosis with a platelet count below 50 × 109 /L. Finally, momelotinib (Ojjaara) is approved for adult patients with intermediate- or high-risk primary or secondary myelofibrosis with anemia.

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Understanding Hematocrit Thresholds in Polycythemia Vera Treatment

March 19, 2025

Author(s): Maggie L. Shaw, Andrew Kuykendall, MD

In early March, The American Journal of Managed Care® spoke with Andrew Kuykendall, MD, a clinical researcher at Moffitt Cancer Center who focuses on myeloproliferative neoplasms (MPNs), myelodysplastic syndrome/MPN overlap syndromes, and systemic mastocytosis. Kuykendall is an investigator on the phase 3 VERIFY trial (NCT05210790) of the injectable hepcidin mimetic rusfertide (Takeda) to treat polycythemia vera (PV) by enabling patients to achieve and sustain hematocrit control.1 Hematocrit is the measure of the percentage of red blood cells in the body.2

Treatment guidelines in PV currently recommend maintaining hematocrit below 45%, with a higher threshold for men vs women.2 For part 2 of this interview, Kuykendall explains the reasoning behind having different hematocrit thresholds.

In the first part of the interview, Kuykendall discussed how PV manifests and common ways to reduce its negative impact on patient quality of life.

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Optimizing Myelofibrosis Care in the Age of JAK Inhibitors

Author: Douglas Tremblay, MD

How do you assess a patient’s prognosis at the time that they are diagnosed with myelofibrosis?
In the clinic, we use several scoring systems that have been developed based on the outcomes of hundreds of patients with myeloproliferative neoplasms (MPNs) to try to predict survival from time of diagnosis. Disease features associated with a poor prognosis include anemia, elevated white blood cell count, advanced age, constitutional symptoms, and increased peripheral blasts. Some of these scoring systems also incorporate chromosomal abnormalities as well as gene mutations to further refine prognostication.1

Determining prognosis can be important to creating a treatment plan, particularly to decide if curative allogeneic stem cell transplantation is necessary. However, I always caution patients that these prognostic scoring systems cannot tell the future and that each patient may respond differently to treatment.

How do you monitor for disease progression?
I will discuss with patients how they are feeling in order to determine if there are any new or developing symptoms that could be a sign that their disease is progressing. I will also review their laboratory work looking for changes in blood counts that could be a signal of disease evolution.

For instance, development of anemia or thrombocytopenia may signal worsening bone marrow function or progression to secondary acute leukemia. If there are concerning signs or symptoms, I will then perform a bone marrow biopsy with aspirate that will include assessment of mutations and chromosomal abnormalities to determine if their disease is progressing.

What are the first-line treatment options for a patient newly diagnosed with myelofibrosis, and how do you determine the best course of action?
For patients with myelofibrosis, the first-line treatment options include Janus kinase (JAK) inhibitors, which are effective at improving spleen size and reducing symptom burden. The US Food and Drug Administration (FDA) has approved 4 JAK inhibitors for the treatment of myelofibrosis: ruxolitinib, fedratinib, pacritinib, and momelotinib (Table).2-13 In general, ruxolitinib is the first-line treatment option unless there is thrombocytopenia, in which case pacritinib is more appropriate. In patients with baseline anemia, momelotinib may be the best choice.

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JAK Inhibitors Reduce Thromboembolic Risk in Myeloproliferative Neoplasm Therapy

March 11, 2025

Author(s): Alex Biese

Fact checked by: Ryan Scott

Treatment with Janus kinase inhibitors (JAKis) has been found to be associated with a reduction in risk of thromboembolic events among patients with myeloproliferative neoplasms (MPNs), according to research findings.

These findings were published in eJHaem, and are driven by observations of treatment with Jakafi (ruxolitinib) for patients with polycythemia vera and myelofibrosis, researchers noted.

“In this meta-analysis, JAKi [used for] MPN [treatment] was associated with a reduced risk of thromboembolic events compared [with] control, primarily driven by studies of [Jakafi] in polycythemia vera and myelofibrosis,” first study author Roberta Dunn and colleagues wrote in the study. “JAKi treatment was not associated with an increased risk of [major adverse cardiovascular events] or hypertension, adding to the existing body of evidence demonstrating the safety of JAKi in the treatment of MPNs. Further prospective clinical trials are warranted to confirm these findings and characterize the cardiovascular profile of other JAKis in all types of MPNs.”

Dunn is a medical student at the School of Medical Education, King’s College London, as well as a student researcher at Guy’s and St Thomas’ NHS Foundation Trust, in the United Kingdom.

MPNs, according to the Cleveland Clinic, are rare blood cancers that involve the patient’s body making too many red blood cells, white blood cells or platelets. JAKis, as explained by the National Cancer Institute, block the actions of enzymes which control cell signaling and growth, the number of blood cells and platelets made in the bone marrow, inflammation, and immune cell activity. Blocking these enzymes may help prevent abnormal blood cells or cancer cells from growing.

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Patients With MF Who Failed Ruxolitinib Treatment May Benefit From Fedratinib

Fedratinib treatment is effective in patients with myelofibrosis (MF) who discontinued ruxolitinib due to treatment failure, according to data from a real-world study published in the scientific journal Future Oncology.

The findings of this study offer a new option for patients with MF whose disease does not respond to ruxolitinib treatment.

To assess the real-world treatment patterns with fedratinib as well as clinical outcomes in patients with primary or secondary MF after ruxolitinib discontinuation, a team of researchers conducted a retrospective, noninterventional medical record review of 196 patients with MF in Germany, Canada, and the United Kingdom.

Data about the patients was provided by 70 physicians of whom 78.6% were primarily hematologists or oncologists.

Of these 196 patients, the majority (76.5%) had primary MF and started treatment with fedratinib at a mean age of 67.7 .

The median duration of treatment with fedratinib was 11.5  months and the median follow-up period was 13.8  months.  Almost half (49.5%) of patients started fedratinib at the dose indicated on the label, i.e. 400  mg per day.

Six months after the start of treatment with fedratinib, 77.7% of patients had symptom response and 66.8% had spleen response.

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Fedratinib Shows Safety, Potential as Post-Transplant Therapy in MPNs

February 21, 2025

Fedratinib (Inrebic) as a maintenance therapy following allogeneic hematopoietic cell transplant given at a 400 mg daily dose was determined to be safe and established as the maximum tolerated dose (MTD) for patients with myeloproliferative neoplasms (MPNs).

Findings come from a recent phase 1 trial where experts explored the potential of fedratinib, a JAK2 inhibitor already approved for pre-transplant myelofibrosis, as a post-transplant maintenance therapy to reduce relapse risk and mitigate graft-vs-host disease (GVHD).

In an interview with Targeted OncologyTM, Hany Elmariah, MD, associate member at the Moffitt Cancer Center in the department of bone marrow transplant and cellular immunotherapy, discussed the trial’s findings, the safety profile of fedratinib, and its evolving role in the post-transplant setting.

Targeted Oncology: Could you discuss the background of this study and what motivated the research?

Elmariah: One of my areas of research is transplant for myelofibrosis and myeloproliferative neoplasms. While transplant can be curative, the cure rate, depending on the study, is generally in the 40% to 60% range. The main reason patients are not cured by transplant is largely the risk of relapse, which [occurs when] the cancer returns after the transplant. For those who do not relapse, there is also the risk of toxicity, such as GVHD, where the transplant attacks the patient’s own body. There are many strategies in development, both for myelofibrosis and other cancers, to reduce the risks of relapse and GVHD.

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Fedratinib in 2025 and Beyond: Indications and Future Applications

Alexander Coltoff (Medical University of South Carolina, United States) John Mascarenhas (Icahn School of Medicine at Mount Sinai, United States)

Abstract

Dysregulated JAK/STAT signaling underlies the pathogenesis of myelofibrosis, a myeloproliferative neoplasm characterized by cytopenias, splenomegaly and constitutional symptoms. JAK inhibitors, such as fedratinib, are the primary therapeutic option for patients with high-risk or symptomatic myelofibrosis. Fedratinib has characteristics that distinguish it from the other commercially available JAK inhibitors, such as its preferential inhibition of JAK2 and its inhibitory effects on kinases such as FLT3 and BRD4. Fedratinib is most often used in the second-line setting after intolerance or resistance to other JAK inhibitors, but there is substantial evidence that it is an effective first-line option in the appropriate patient population. Prevention and early treatment of fedratinib-related gastrointestinal toxicity is key to maintaining adequate drug exposure, and clinicians must remain vigilant for Wernicke encephalopathy during treatment. Fedratinib’s JAK2 selectivity and kinome profile make it an appealing agent for alternative indications, such as myelodysplastic/myeloproliferative neoplasms and maintenance after bone marrow transplantation, which are under active investigation.

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Second-Line Fedratinib Produces Early Platelet Count Improvements in Myelofibrosis

February 5, 2025

Author(s): Jax DiEugenio

Fact checked by: Chris Ryan

Patients with myelofibrosis who received second-line fedratinib (Inrebic) experienced early increases in platelet count compared with those given best available therapy (BAT), and a higher magnitude of benefit was observed in patients with a low platelet count at baseline, according to findings from the phase 3 FREEDOM2 trial (NCT03952039) presented at the 2024 ASH Annual Meeting.

Findings showed that in the overall safety population, fedratinib generated improvements in mean platelet count and mean change from baseline platelet count, most noticeably in early treatment cycles.

In patients with a low platelet count at baseline, defined as at least 50 to less than 100 x 109/L, patients treated with fedratinib (n = 34) experienced a mean increase in platelet count of 45% on day 15 of cycle 1 compared with 11% for those given BAT (n = 21). Among patients with a high platelet count at baseline of at least 100 x 109/L, these rates were 27% for fedratinib (n = 85) and –6% for BAT (n = 39).

During a presentation of the data, lead study author Haifa Kathrin Al-Ali, MD, explained that increased platelet count was not correlated with changes in spleen size, pointing to a potential benefit for fedratinib on thrombopoiesis.

“These data suggest a platelet-sparing effect of second-line fedratinib vs BAT, and support fedratinib as a promising second-line treatment option for patient with myelofibrosis with low or high baseline platelet count,” said Al-Ali, who is a professor of translational oncology and head of the Krukenberg Cancer Center at the University Hospital of Halle (Saale) in Germany.

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