Fedratinib Shows Promise in Long-Term MPN Success With Tolerable Toxicity

By Hany Elmariah, MD

A phase 1 trial investigated the safety and tolerability of maintenance therapy with the JAK2 inhibitor fedratinib (Inrebic) following allogeneic hematopoietic cell transplant (HCT) for myeloproliferative neoplasms (MPNs) and myelodysplastic syndrome/MPN overlap syndromes.

While HCT offers potential cure for MPNs, posttransplant relapse remains a significant challenge. Fedratinib, effective in myelofibrosis, with a favorable safety profile and oral administration, presents a rational strategy to reduce relapse and potentially prevent graft-vs-host disease (GVHD) while preserving the graft-vs-tumor (GVT) effect.

“Usually with fedratinib, the main toxicities are cytopenia, so low blood counts. We also see a fair amount of [gastrointestinal (GI)] toxicity, nausea, vomiting, or diarrhea,” said Hany Elmariah, MD, associate member at the Moffitt Cancer Center in the Department of Bone Marrow Transplant and Cellular Immunotherapy, in an interview with Targeted OncologyTM.

The study enrolled patients post-HCT who received fedratinib between days +60 and +100 for up to 1 year. The trial utilized a 3+3 design to determine the maximum tolerated dose (MTD). Eleven patients were evaluable for dose-limiting toxicities (DLTs). The MTD was identified as 400 mg daily. While no DLTs occurred within the 30-day window, 4 patients withdrew due to non-DLT adverse events. Notably, only 1 patient developed severe chronic GVHD. The median progression-free survival was 12.4 months, and the 1-year overall survival was 100%.

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New Trial Will Assess Safety and Efficacy of MF Drug

Publish Date

A clinical trial aiming to determine the efficacy, safety, and pharmacokinetics of the experimental drug WJ01024 combined with ruxolitinib in patients with myelofibrosis (MF) is set to begin soon.

“Although the clinical efficacy of ruxolitinib tablets has been confirmed, only about half of MF patients can achieve the ideal therapeutic effect (≥35% reduction in spleen volume and ≥50% improvement in disease symptoms at 24 weeks),” the authors wrote. “Therefore, there is an urgent need for innovative drugs that can be combined with ruxolitinib tablets to enhance therapeutic efficacy and meet clinical needs,” they added.

WJ01024 aims to enhance the therapeutic efficacy of ruxolitinib through  XPO-1 inhibition. Previous in vitro studies have confirmed that the drug enhances ruxolitinib anti-cell proliferation activity, the researchers noted. Furthermore, preliminary studies on humans suggest that WJ01024 is effective as monotherapy for relapsing patients and those intolerant to JAK inhibitors, they added.

The trial will consist of a dose escalation and a dose extension phase (phase 1a and phase 2). Phase 1b will divide patients into three groups receiving 40 mg, 60 mg, and 80 mg of WJ01024, respectively. Phase 2 will be an open-label evaluation of the efficacy and safety of the recommended dose in combination with ruxolitinib.

The study will only include patients diagnosed with MF and with the international prognostic scoring system risk category of intermediate-1, intermediate-2, or high-risk. Patients in the accelerated blast phase or previous treatment with either JAK or XPO-1 inhibitors are not eligible for participation.

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Safety and Efficacy of Busulphan Based on Dosing Patterns in the Real‐World Management of Myeloproliferative Neoplasms

March 2025

Ali Mahdi, Alexandros Rampotas, Patrick Roberts, Joanna Stokes

Abstract

Introduction
Myeloproliferative neoplasms (MPNs), such as polycythaemia vera (PV), essential thrombocythemia (ET) and myelofibrosis (MF), are primarily treated by managing blood counts to reduce the thrombotic risk using cytoreductive agents. Busulphan, an oral alkylating agent, has been historically used for MPN management due to its myelosuppressive effects, but concerns about its risk of leukaemic transformation have limited its use.
Methods
This real‐world retrospective study evaluated the safety and efficacy of busulphan in 115 MPN patients across 13 UK hospitals. Responses in patients with ET and PV only were assessed using European LeukemiaNet (ELN) criteria.
Results
With a median age of 78 years, the overall response rate was 78.1%, with 29% of PV and 18% of ET patients achieving complete responses. Dosing regimens were similarly distributed between repeated single doses of busulphan (31%), courses of treatment lasting 1–4 weeks (30%) and continuous therapy for more than 4 weeks (35%). No cases of disease progression to acute leukaemia or myelofibrosis were recorded during the median follow‐up of 23 months. Adverse events were infrequent, with fatigue and cytopaenia being the most common (4% each).
Conclusion
Busulphan demonstrated a favourable safety profile and is a viable cytoreductive option, particularly for elderly patients who are intolerant to hydroxycarbamide.

Pelabresib Plus Ruxolitinib Improves Spleen Responses in Myelofibrosis

By Roman Fabbricatore
Fact checked by Russ Conroy

Pelabresib (CPI 0610) in combination with ruxolitinib (Jakafi) significantly improved spleen responses and elicited robust clinical activity compared with placebo/ruxolitinib in patients with JAK inhibitor-naïve myelofibrosis, according to results from the phase 3 MANIFEST-2 trial (NCT04603495) published in Nature Medicine.1

Efficacy data from the trial revealed that the primary end point of spleen volume reduction of at least 35% at week 24 favored the investigational combination vs the placebo arm: 65.9% vs 35.2%, respectively (difference, 30.4%; 95% CI, 21.6%-39.3%; P <.001). Additionally, the mean percent change at week 24 in the respective arms was –50.6% (95% CI, –53.2% to –48.0%) vs –30.6% (95% CI, –33.7% to –27.5%). Spleen volume response was consistently higher with pelabresib vs placebo across predefined subgroups.

Furthermore, the hemoglobin response rate, defined as a 1.5 g/dl or greater mean increase, occurred in in 10.7% of the pelabresib arm (95% CI, 6.60%-14.90%) vs 6.0% of the placebo arm (95% CI, 2.85%-9.19%). Transfusions were received in the first 24 weeks of treatment in 27.6% and 37.5% of respective arms.

Greater reductions in NF-κB-regulated cytokines (–32.1% [95% CI, –34.9% to –29.2%] vs –19.4% [95% CI, –22.5% to –16.2%]), tumor necrosis factor (TNF; –43.5% [95% CI, –47.0% to –39.8%] vs –26.4% [95% CI, –30.5% to –22.1%]), and interleukin-6 (IL-6; –35.4% [95% CI, –44.2% to –25.2%] vs –14.5% [95% CI, –25.2% to –2.3%]) were seen in the investigational arm vs the placebo arm. Of note, a reduction in IL-8 levels was observed with pelabresib (–14.3% [95% CI, –22.3% to –5.5%]), but an increase was observed in the placebo arm (31.2% [95% CI, 17.5%-46.5%).

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Dr Rampal on ​Emerging Therapies Under Investigation in Myelofibrosis

March 17, 2025

Author(s): Raajit K. Rampal, MD, PhD

Fact checked by: Ashling Wahner ,Chris Ryan

Raajit Rampal, MD, director of the Center for Hematologic Malignancies and director of the Myeloproliferative Neoplasms Program at Memorial Sloan Kettering Cancer Center, discusses emerging treatments for patients with myelofibrosis.

The therapeutic paradigm for myelofibrosis continues to expand with emerging treatment options, particularly with combination therapies, novel JAK inhibitors, and immunotherapeutic agents, Rampal begins. Among these, pelabresib (CPI-0610), a BET inhibitor, has completed phase 3 trials. Preliminary data from the phase 3 MANIFEST-2 trial (NCT04603495), which were presented in December 2023, demonstrated improved spleen responses and a trend toward better symptom management with the combination of pelabresib and ruxolitinib (Jakafi) vs placebo plus ruxolitinib in patients with JAK inhibitor–naive myelofibrosis. Updated findings from MANIFEST-2 were published in Nature Medicine in March 2025.

Beyond pelabresib, several other agents are currently in phase 3 trials for patients with myelofibrosis, Rampal says. Selinexor (Xpovio), which is currently FDA approved for the treatment of patients with relapsed/refractory multiple myeloma, is being studied in combination with ruxolitinib in patients with myelofibrosis in the phase 3 XPORT-MF-034 trial (NCT04562389). Additionally, navtemadlin (KRT-232), an MDM2 inhibitor, is undergoing clinical evaluation in patients with myelofibrosis. Notably, these trials are ongoing, and no conclusive data are available at this time, Rampal emphasizes.

The development of next-generation JAK inhibitors also represents a promising area of investigation, according to Rampal. These newer inhibitors are anticipated to demonstrate greater potency and selectivity compared with existing agents, though they remain in early-phase clinical trials, he notes.

Rampal states that one of the most exciting advancements in this setting is the emergence of immunotherapies. Calreticulin-targeted antibodies are currently being evaluated in clinical trials, and 2 candidates are in development, he reports. If these agents prove effective, they could significantly alter the treatment paradigm, he concludes.

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Promising New Treatment for Myelofibrosis Blood Cancer Using a Combination Targeted Therapy 

By 

An international phase 3 clinical trial of a new drug combination for treating the blood cancer myelofibrosis found that adding a second, experimental drug to standard treatment was more effective than the standard treatment alone. Further, adding the second drug did not significantly increase side effects. Memorial Sloan Kettering Cancer Center (MSK) enrolled the most patients in the trial.

“This is one of the largest myelofibrosis clinical trials to date,” says MSK leukemia specialist Raajit Rampal, MD, PhD, lead author of the study, published March 10 in Nature Medicine. “There is a real unmet need for patients with this disease, and the findings from this trial represent an exciting advance.”

This study looked at adding an experimental drug called pelebresib to the drug ruxolitinib (Jakafi®), which is the current treatment for myelofibrosis. Both drugs are targeted therapies. Pelebrisib blocks the action of proteins involved in inflammation and cancer; ruxolitinib blocks a protein called JAK. This combination approach was based on ongoing research from the lab of MSK leukemia specialist and physician-scientist Ross Levine, MD.

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New MF Study Recruiting Participants for Its Phase 3 Portion

A phase 1/3 clinical trial testing the safety and efficacy of selinexor plus ruxolitinib in patients with myelofibrosis (MF) who are Janus kinase (JAK) inhibitor-naïve is now recruiting participants for its phase 3 portion.

The global, multicenter, 2-part study aims to recruit an estimated 350 participants with MF. Participants were all at least 18 years of age.

The study consists of an experimental phase 1a, experimental phase 1b, and experimental phase 3 portion.

In the experimental phase 1a portion, 1 group of patients were given 40 mg of oral selinexor once a week on days 1, 8, 15, and 22 of each 28-day cycle together with 15 or 20 mg of ruxolitinib twice a day based on their platelet count at baseline while another group was given 60 mg of oral selinexor on the same days and the same dose of ruxolitinib as the first group.

In the experimental phase 1b, patients were given either 40 or 60 mg of oral selinexor once a week on days 1, 8, 15, and 22 of each 28-day cycle and the same dose of ruxolitinib.

In the experimental phase 3 portion, patients will either be given a fixed starting dose of 60 mg of oral selinexor or a placebo once a week on days 1, 8, 15, and 22 of each 28-day cycle together with the same dose of ruxolitinib.

The primary outcome measures of the phase 1 portion of the trial was the maximum tolerated dose and recommended phase 2 dose of selinexor and the number of participants with adverse events by severity, nature, and occurrence.

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What to Know About Myeloproliferative Disorders Clinical Trials

Medically reviewed by Julie Scott, DNP, ANP-BC, AOCNP — Written by Hope Gillette on March 6, 2025

Myeloproliferative disorders, now referred to as myeloproliferative neoplasms (MPNs), include a group of blood cancers that develop when bone marrow produces too many red blood cells, white blood cells, or platelets.

Some forms of MPNs, such as essential thrombocythemia (ET) respond well to current treatmentTrusted Source, but others, such as primary myelofibrosis, have fewer effective options.

Depending on the specific diagnosis you received, your healthcare team may recommend participating in an MPN clinical trial to expand your treatment possibilities.

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Protagonist and Takeda Announce Positive Topline Results from Phase 3 VERIFY Study of Rusfertide in Patients with Polycythemia Vera

March 3, 2025

− Study met the primary endpoint, with a significantly higher proportion of clinical responders on rusfertide compared to placebo

− All four key secondary endpoints were met, including EU primary endpoint and patient-reported outcomes

− Rusfertide was generally well tolerated; no new safety findings were observed in the study

NEWARK, Calif. & OSAKA, Japan & CAMBRIDGE, Mass.–(BUSINESS WIRE)–Protagonist Therapeutics, Inc. (“Protagonist”) (NASDAQ:PTGX) and Takeda (TSE:4502/NYSE:TAK) today announced positive topline results for the Phase 3 VERIFY study, in which phlebotomy-dependent patients with polycythemia vera (PV) were randomized to treatment with either rusfertide or placebo, as an add-on to standard of care treatment. The study met its primary endpoint and all four key secondary endpoints. Rusfertide is a first-in-class investigational hepcidin mimetic peptide therapeutic, which has received Orphan Drug designation and Fast Track designation from the U.S. Food & Drug Administration (FDA).

Key findings from the study include:

  • The primary endpoint of the study was met, with a significantly higher proportion of clinical responders1 among rusfertide-treated patients with PV (77%) compared to those who received placebo (33%) during weeks 20-32; p<0.0001. The primary endpoint of the study was the proportion of patients achieving a response, which was defined as the absence of phlebotomy eligibility.
  • The first key secondary endpoint, which is the pre-specified primary endpoint for European Union (EU) regulators, was also met, with a mean of 0.5 phlebotomies per patient in the rusfertide arm compared to 1.8 phlebotomies per patient in the placebo arm during weeks 0-32; p<0.0001.
  • The other three pre-specified key secondary endpoints, namely hematocrit control2 and patient-reported outcomes using PROMIS Fatigue SF-8a3 and MFSAF TSS-74, were also achieved with statistical significance.
  • Rusfertide was generally well tolerated in the Phase 3 VERIFY trial, and safety was in line with previous rusfertide clinical studies. No new safety findings were observed in the study. The majority of adverse events were grade 1-2 injection site reactions and all serious adverse events reported were deemed to be not drug related. There was no evidence of an increased risk of cancer in rusfertide-treated patients compared to those on placebo.

“The positive results of the Phase 3 VERIFY study across the primary and all key secondary endpoints provide compelling evidence of the potential for rusfertide as a first-in-class erythrocytosis-specific agent to address unmet medical needs in patients with PV who are unable to achieve adequate hematocrit control despite standard of care treatments,” said Arturo Molina, M.D., M.S., Chief Medical Officer of Protagonist. “We plan to submit additional details of these promising results for presentation at upcoming medical conferences in 2025. We are immensely grateful to the patients, study staff and principal investigators who made the VERIFY study possible.”

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Divesiran Is Tolerable and Shows Positive Early Signals in Polycythemia Vera

February 26, 2025

Author(s): Kyle Doherty

Fact checked by: Megan Hollasch

Divesiran (SLN124), a novel small interfering RNA (siRNA), was safe and displayed signals of efficacy in the treatment of patients with polycythemia vera, according to findings from the phase 1/2 SANRECO trial (NCT05499013).1

Initial results from SANRECO presented during the 2024 ASH Annual Meeting showed that divesiran reduced phlebotomy frequency in patients (n = 21). A total of 79 phlebotomies occurred across all patients prior to dosing; there were 5 phlebotomies during the treatment period and 2 during follow-up among all patients. Divesiran also induced hepcidin in all patients and decreased hematocrit in all cohorts of patients treated.

Additionally, patients did not experience any dose-limiting toxicities. Most treatment-emergent adverse effects (TEAEs) were grade 1 in severity (84%) and there were no TEAEs above grade 2 reported. There were also no treatment-related serious AEs or TEAEs leading to treatment discontinuation.

Divesiran is a first-in-class GalNAc-conjugated siRNA that targets TMPRSS6, a negative regulator of the HJV/BMP/SMAD signaling pathway that induces hepcidin expression. The agent is designed to have a long duration of action, and, notably, it’s target sequence is unique to TMPRSS6 and was selected to maximize TMPRSS6 knock down. Investigators hypothesized that inhibiting TMPRSS6 would raise hepcidin levels and lower iron delivery to the bone marrow, leading to reduced erythropoiesis.

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