Fedratinib Shows Promise in Rare Myeloproliferative Neoplasms

By Andrew Kuykendall, MD

Andrew Kuykendall, MD, an assistant member at the H. Lee Moffitt Cancer Center of University of South Florida in Tampa, FL, discusses data from a phase 2 trial (NCT05177211) which evaluated fedratinib (Inrebic), a JAK2-selective kinase inhibitor, in patients with atypical chronic myeloid leukemia (aCML), chronic neutrophilic leukemia (CNL), myelodysplastic syndrome (MDS)/myeloproliferative neoplasm (MPN)-unclassifiable, and MDS/MPN-ring sideroblasts and thrombocytosis per the 2016 WHO classification.

According to findings from this multi-institutional, investigator-initiated study presented at the 2024 American Society of Hematology (ASH) Annual Meeting, fedratinib demonstrated promising efficacy and a manageable safety profile in this patient population.

At the time of data cutoff, 24 patients were enrolled and 19 patients were evaluable. A total of 53% of patients achieved a response at 24 weeks, including 50% symptom responses and 37.5% spleen responses. Of those treated for ≥24 weeks, spleen volume decreased by an average of 32%, and 85% showed symptomatic improvement. Responses were enriched in patients with CSF3R mutations (83%) and JAK-STAT pathway mutations (70%). Further, the median overall survival (OS) was estimated at 19.7 months.

“This was a very high-risk population, as these diagnoses are associated with poor prognosis. Despite that, we observed spleen responses in approximately 35% of patients, symptom responses in 50%, and some durable responses, with the median time on treatment nearing a year. These outcomes were particularly exciting given the molecular features of this patient population, which typically predict lower response rates,” Kuykendall shares.

Safety findings showed that fedratinib was well tolerated, The majority of adverse events (AEs) were grades 1 or 2, and the most commonly seen AEs were diarrhea (37.5%), constipation (37.5%), and anemia (29%). A single grade 4 neutropenia event resolved with dose adjustments.

“Regarding the safety profile, it was consistent with prior studies of fedratinib. There were some manageable low-grade gastrointestinal [adverse events]. We implemented a more proactive approach to mitigate these, including the use of antiemetics during the first 8 weeks. Overall, the [adverse event] profile remained manageable, and the efficacy outcomes likely exceeded our initial expectations,” adds Kuykendall.

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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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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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Real-world treatment patterns and health outcomes for patients with myelofibrosis treated with fedratinib

January 14, 2025

Francesco Passamonti Shalon Jones e , a,b , Siddhi Korgaonkar c Dorothy Zissler e , , Keith L Davis Rohan C Parikh c c , Manoj Chevli d , and Samantha Slaff

ABSTRACT

Aim: Assess real-world fedratinib (FEDR) treatment patterns and clinical outcomes in patients with primary or secondary myelofibrosis following discontinuation of ruxolitinib (RUX). Patients & Methods: This study was a retrospective, noninterventional medical record review of patients in Canada, Germany, and the United Kingdom (UK). A total of 70 physicians (primarily hematologist-oncologists [78.6%]) provided data for 196 eligible patients.

Results: Patients were mostly male (62.8%) with primary myelofibrosis (76.5%) and initiated FEDR at a mean age of 67.7 years. Median treatment duration was 11.5 months (median follow-up, 13.8 months), and nearly half (49.5%) of patients initiated FEDR at the label-indicated dose of 400 mg daily. Six months post-initiation, 77.7% and 66.8% of patients experienced symptom and spleen response, respectively. Kaplan-Meier estimates of median progression-free and overall survival from initiation were 23.8 months (95% CI, 21.1–27.6) and 29.8 months (95% CI, 23.9-NE), respectively.

Conclusion: These findings demonstrate real-world FEDR effectiveness among patients with myelofibrosis who discontinued RUX.

PLAIN LANGUAGE SUMMARY

What is this summary about?

Myelofibrosis (MF) is a rare blood cancer that can cause unhealthy spleen growth and symptoms, such as feeling tired, loss of appetite, bone pain, and fever. This is a summary of an article that reviewed medical records of patients with MF from treatment centers in Canada, Germany, and the United Kingdom (UK). The study looked at people who had been taking a medication called fedratinib (FEDR) for their MF after they had stopped taking a different medication called ruxolitinib (RUX). Many of the people stopped taking RUX because their MF got worse within a few years. The study wanted to see if taking FEDR reduced symptoms and spleen size for people with MF after they stopped taking RUX.

What were the results?

After at least 6 months of taking FEDR, 77.7% of the people in the study had fewer symptoms, and 66.8% of people in the study had a decrease in spleen size or no spleen growth. Additionally, most people taking FEDR after discontinuing RUX went nearly 2 years without their MF symptoms or illness getting worse.

What do the results mean?

These results suggest that FEDR is an effective treatment for people with MF who have stopped taking RUX.

Fedratinib for the treatment of myelofibrosis: a critical appraisal of clinical trial and “real-world” data

January 14, 2025

Adrian Duek, Ilona Leviatan, Osnat Jarchowsky Dolberg & Martin H. Ellis

Abstract

Fedratinib is a predominantly JAK2 inhibitor that has shown efficacy in untreated and ruxolitinib-exposed patients with myelofibrosis (MF). Based on randomized clinical trial data, it is approved for use in patients with International Prognostic Scoring System (IPSS) or Dynamic International Prognostic Scoring System (DIPSS) intermediate-2 or high-risk disease and is distinguished from ruxolitinib in that it can be administered without dose reduction in patients with thrombocytopenia, to a platelet count above 50,000/µL. In these trials, fedratinib achieved significant spleen volume reduction in ~30–45% of patients and improvement in total symptom scores in 35–40% with good tolerability. In contrast, recently published real-world data suggest that these responses may not be as robust outside clinical trials. In the context of routine clinical practice spleen responses are documented in only 13–68%, with varying degrees of symptom improvement. This may be due to the lack of a uniform definition of ruxolitinib failure, which may influence the timing of initiating fedratinib as a second-line treatment and result in a more prolonged exposure to ruxolitinib prior to intitaing fedratinib treatment. We suggest that given the growing number of drugs available for use in MF, recognizing the failure of first-line (and potentially subsequent) treatments is critical to allow timely transition to potentially more active agents, as highlighted by the data pertaining to fedratinib.

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Fedratinib Alleviates Symptoms, Reduces Spleen Volume in MDS, MPNs

Fedratinib can reduce symptoms and spleen volume in patients with myelodysplastic syndrome (MDS) or myeloproliferative neoplasms (MPNs), according to research presented at the ASH Annual Meeting 2024.

Researchers are evaluating fedratinib, a JAK2 inhibitor, in a phase 2 trial. The trial (NCT05177211) enrolled 25 patients with atypical chronic myeloid leukemia (n=6), chronic neutrophilic leukemia (n=5), MDS/MPN-unclassifiable (n=8), and MDS/MPN with ring sideroblasts and thrombocytosis (n=6).

At baseline, the median patient age was 68.8 (range, 39.9-84.7) years, and the median time from diagnosis to treatment was 7.1 months. Most patients had splenomegaly (83%), and the median MPN-Symptom Assessment Form Total Symptom Score was 21 (range, 1-73). Prior treatments included hydroxyurea (36%), ruxolitinib (20%), luspatercept (8%), and hypomethylating agents (12%). Patients had a median of 3 pathogenic mutations.

“Most of these patients had multiple mutations, and most had a signaling mutation, an epigenetic mutation, and a splicing mutation,” said study presenter Andrew Kuykendall, MD, of the Moffitt Cancer Center in Tampa, Florida.

The patients received fedratinib at a dose of 400 mg daily in 28-day cycles. They could continue on treatment as long as they had a clinical benefit. At last follow-up, 11 patients were still on study treatment.

The median duration of fedratinib treatment was 10.8 months, and 21 patients were evaluable for efficacy at 24 weeks. Three patients discontinued fedratinib prior to 24 weeks for reasons unrelated to toxicity or lack of efficacy (eg, cost) and were considered non-responders.

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FREEDOM2 Trial Shows Fedratinib’s Efficacy and Safety in Myelofibrosis

By Jordyn Sava
Fact checked by Sabrina Serani

When given as a second-line JAK inhibitor option in patients with myelofibrosis, fedratinib (Inrebic) showed its effectiveness in achieving spleen volume reduction (SVR) while highlighting strategies for managing gastrointestinal adverse effects (AEs) and thiamine deficiency, according to findings from the FREEDOM2 study (NCT03952039).1

The FREEDOM2 study, a multicenter, open-label, randomized controlled trial, involved 316 patients with intermediate-2 or high-risk myelofibrosis who were either relapsed, refractory, or intolerant to ruxolitinib (Jakafi).2 The median follow-up for survival at the data cutoff on December 27, 2022, was 64.5 weeks (IQR, 37.9-104.9). The primary end point was the proportion of patients achieving an SVR of at least 35% (SVR35) at the end of cycle 6.

Results from the study demonstrated a significant difference in SVR35 between the fedratinib and best available therapy (BAT) groups, with 36% of patients in the fedratinib group achieving the primary end point compared with only 6% in the BAT group (30% difference; 95% CI 20%-39%; 1-sided P <.0001).1

“Findings from FREEDOM2 support fedratinib as a second-line Janus kinase inhibitor option to reduce spleen size after ruxolitinib failure or intolerance in patients with myelofibrosis,” wrote study authors in findings published in The Lancet Hematology.

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