Selinexor Paves the Way for More Affordable, Effective Treatment Options in Myelofibrosis

October 14, 2024

Author(s): Courtney Flaherty

Fact checked by: Caroline Seymour

Attempts to leverage drugs that are effective in combination, such as selinexor (Xpovio), as single agents for the management JAK inhibitor–naive myelofibrosis reflects the need for improved personalization of therapy according to individual factors, and mitigation of financial toxicities associated with standard JAK inhibitor–based regimens, according to Joseph M. Scandura, MD, PhD.

Selinexor, an oral exportin 1 inhibitor potentially targeting both JAK/STAT and non-JAK/STAT pathways, has previously demonstrated efficacy when used in combination with ruxolitinib (Jakafi) in the phase 1/3 SENTRY trial (XPORT-MF-034; NCT04562389). Results from the phase 1 portion of the trial showed a 35% or greater reduction in spleen volume (SVR35) at weeks 12 and 24 in 71% and 79% of patients treated with 60 mg of selinexor plus ruxolitinib in the intention-to-treat (ITT) population (n = 14), respectively. Moreover, 58% of patients who achieved symptom improvement of at least 50% (TSS50) at week 24 in the ITT population (n = 12) remained in response at the data cutoff of August 1, 2023.1,2

In July 2023, the FDA granted fast track designation to single-agent selinexorfor the treatment of patients with myelofibrosis, including primary myelofibrosis, post-essential thrombocythemia myelofibrosis, and post-polycythemia vera myelofibrosis.3

Selinexor will be evaluated in combination with ruxolitinib in the phase 3 portion of SENTRY,1 and as monotherapy in the phase 2 SENTRY-2 study (XPORT-MF-044; NCT05980806) in JAK inhibitor–naive patients with myelofibrosis.4

“The big thing that differentiates the [SENTRY-2] study is that it’s testing selinexor [alone] and only adding the JAK inhibitor [to selinexor] when it is needed, and it matches the patients’ characteristics. It’s not a one-size-fits-all study,” said Scandura, who is an associate attending physician at NewYork-Presbyterian Hospital and an associate professor of medicine at Weill Cornell Medical College, Cornell University, in New York. “This allows patients to be treated similarly to clinical practice in the context of a clinical trial…and allows us to [learn whether] one of these drugs works much better with selinexor than the other.”

In an interview with OncLive®, Scandura discussed selinexor’s mechanism of action, reviewed clinical data supporting its potential use both alone and in combination with JAK inhibitors in myelofibrosis, and highlighted how approval of this agent as monotherapy could help alleviate financial burdens associated with JAK inhibitor–based regimens.

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JAK Inhibitors Diversify the Field of Myelofibrosis Symptom and Spleen Management

October 8, 2024

Author(s): Ashling Wahner

Fact checked by: Courtney Flaherty

The wealth of JAK inhibitors available for managing myelofibrosis invites the development of increasingly personalized treatment plans based on individual patient needs and disease characteristics, according to Idoroenyi Amanam, MD.

“We’ve come a long way since ruxolitinib [Jakafi] was FDA approved,” Amanam said in an interview with OncLive®. “We have a better understanding of which patients benefit from JAK inhibitors, and we are clearer on the shortcomings of JAK inhibitors.”

In the interview, Amanam discussed how JAK inhibitors measure up against other available therapies in myelofibrosis; patient characteristics that are most likely to indicate benefit with JAK inhibitors; and which of these agents he is likely to choose based on patients’ platelet counts, symptom burden, and treatment history.

For instance, Amanam highlighted the importance of pacritinib (Vonjo) in the myelofibrosis treatment paradigm. Pacritinib was approved by the FDA in 2022 for the treatment of select adult patients with intermediate- or high-risk myelofibrosis with thrombocytopenia based on findings from the phase 3 PERSIST-2 trial (NCT02055781), in which 29% patients who received the agent achieved a spleen volume reduction (SVR) of at least 35%. Among patients who received best available therapy, the SVR rate was 3%.1

He also explained the role of momelotinib (Ojjaara) for patients with anemia. Momelotinib was FDA-approved in 2023 for the treatment of adult patients with intermediate- or high-risk myelofibrosis and anemia based on data from the phase 3 MOMENTUM trial (NCT04173494).2 In MOMENTUM, 25% of patients who received momelotinib (n = 32/130) experienced a Myelofibrosis Symptom Assessment Form 4.0 total symptom score reduction of at least 50% vs 9% of those who received danazol (Danocrine; n = 6/65), translating to a treatment difference of 16% (95% CI, 6%-26%; < .0095).3

Amanam is an assistant professor in the Division of Leukemia in the Department of Hematology & Hematopoietic Cell Transplantation at City of Hope in Duarte, California.

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Study Findings Suggest Use of Fedratinib as Treatment in the Second Line for Myelofibrosis

October 3, 2024

Author(s): Alexandra Gerlach, Associate Editor

Fedratinib (Inrebic; Bristol Myers Squibb) demonstrates safety and efficacy as a second line Janus kinase inhibitor (JAKi) option to reduce spleen size after ruxolitinib (Jakafi; Incyte Corp) failure or intolerance in patients with myelofibrosis (MF), according to results from the FREEDOM2 trial (NCT03952039). The study compared treatment with fedratinib and the best available therapy (BAT) in intermediate- or high-risk primary MF.1

The results support the potential of fedratinib as a JAK-2 inhibitor in the second line as a therapeutic option for patients intolerant or resistance to ruxolitinib.

Image Credit: © NeuroGraphix Studio – stock.adobe.com

MF is an uncommon, fatal myeloproliferative neoplasm characterized by the overproduction hematopoietic stem cells, leading to increasingly reduced red blood cell production. As a result, many patients with MF, approximately 40%, have anemia at diagnosis, of which an estimated 25% are RBC transfusion dependent (TD). In most cases, patients will develop chronic anemia and TD as the disease progresses.2,3

Ruxolitinib is a JAKi approved by the FDA in 2011 and indicated for the treatment of patients with intermediate or high-risk myelofibrosis, including primary MF (PMF), post-polycythemia vera MF (post-PV MF) and post-essential thrombocythemia MF (post-ET MF). Despite its success for some patients, the response rate is less than 50% and survival rates after ruxolitinib discontinuation are poor. Many patients develop ruxolitinib intolerance and become relapsed or refractory.4,5

Fedratinib is an orally available, small molecule inhibitor of JAK-2, which is often mutated in patients with MF. It was approved in 2019 by the FDA as a therapeutic option for intermediate- or high-risk primary or secondary MF and has demonstrated clinically meaningful benefits for patients. In multiple preregistration trials, fedratinib resulted in reduction spleen size and improvement in symptoms in 40% to 50% of patients, including those who were resistant or intolerant to ruxolitinib.6

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Novel Biomarker Could Predict MF Progression

C-mannosyl tryptophan could be a novel biomarker to predict the progression of myelofibrosis (MF) in thrombocytosis of myeloproliferative neoplasms, according to a new study published in the journal Scientific Reports.

“Present studies evaluating C-mannosylation using this novel assay for progression to overt MF in [essential thrombocythemia] may provide promising future directions,” the researchers wrote.

To assess C-mannosyl tryptophan in human hematological diseases, the team, led by Shinobu Tamura, PhD, from the Wakayama Medical University in Japan, quantified the levels of the amino acid in the serum of 94 healthy people using hydrophilic interaction liquid chromatography.

They found that the platelet count was positively correlated with the levels of C-mannosyl tryptophan in the serum.

They then assessed the clinical significance of C-mannosyl tryptophan in thrombocytosis of myeloproliferative neoplasms, including essential thrombocythemia, by measuring the levels of the amino acid in the serum of 34 patients with thrombocytosis of myeloproliferative neoplasms and compared this to the levels in the serum of 52 patients with other hematological disorders.

They found that serum levels of C-mannosyl tryptophan were significantly higher in patients with thrombocytosis. Moreover, the amino acid’s serum levels were inversely correlated with anemia, which was related to MF.

Finally, the researchers analyzed the bone marrow biopsy samples of 18 patients with essential thrombocythemia and measured the levels of C-mannosyl tryptophan in their serum at the same time. They found that 12 patients with bone marrow fibrosis had significantly higher levels of C-mannosyl tryptophan compared to the 6 patients without bone marrow fibrosis.

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Janus kinase inhibitor monotherapy and combination therapies for myelofibrosis: what’s the current standard of care?

Received 10 Jun 2024, Accepted 23 Sep 2024, Published online: 03 Oct 2024

ABSTRACT

Introduction

JAK inhibitors (JAKi) have changed the treatment paradigm of myelofibrosis (MF). Currently, 4 JAKis are approved in the US as monotherapy (mono) to treat patients with MF. JAKis are also being studied in combination (combo) with novel agents. Herein, we review some of the key studies that evaluated JAKi as mono and combo in MF.

Areas covered

We performed a Pubmed search for ‘JAK inhibitors’ and ‘myelofibrosis’ from 1/2010 to 12/2023. For mono, we included only the unique phase II/III studies of the approved JAKi. Selective studies that evaluated JAKi in combo with the novel agents were also included.

Expert opinion

JAKis aim to provide clinical benefit to patients via spleen size reduction and MPN symptom improvement. In order to potentially increase clinical benefit for patients with MF, several novel agents are being partnered with ruxolitinib (RUX) with the ongoing hypothesis to augment greater measures of MF disease modification. The novel agents are either ‘added-on’ to RUX or as a combo in JAKi naïve patients. Also, the mutant-targeting era of therapies is now beginning with novel CALR-mutated, novel JAK2 V617F mutation-specific and type II JAK2i in the initial stages of drug development, representing a new approach to treatment.

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Choosing the Right JAK Inhibitor for Effective Myelofibrosis Treatment

By Jordyn Sava
Fact checked by Sabrina Serani

With 4 JAK inhibitors approved in the US and additional agents in development, it is an exciting time for the field of myeloproliferative neoplasms (MPNs). Now, experts face the challenge of determining which treatment is best for each patient.

Ruxolitinib (Jakafi), an established JAK inhibitor, was first approved by the FDA in 2011,showing clear survival benefits. This was followed by the FDA approvals of fedratinib (Inrebic) in 2019,2 pacritinib (Vonjo) in 2022,3 and momelotinib (Ojjaara) in 2023.4

“Each [JAK inhibitor has] their place depending on the patient’s blood counts and other clinical factors,” explained Prithviraj Bose, MD, in an interview with Targeted OncologyTM.

With multiple JAK inhibitors available to choose from, a tailored approach ensures that each patient’s specific disease characteristics and comorbidities are considered to maximize efficacy and minimize toxicity during treatment.

In the interview, Bose, professor in the Department of Leukemia at MD Anderson Cancer Center, discussed the multiple JAK inhibitors available for the treatment of patients with MPNs.

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Ruxolitinib Could Be Useful in MF Care

Ruxolitinib appears to produce durable responses and minimal adverse effects in patients with myelofibrosis (MF) in a real-world setting, according to a recently published study in Cancer.

Since its US Food and Drug Administration approval over a decade ago, the JAK1/JAK2 inhibitor ruxolitinib has become one of the most commonly used drugs for the management of MF-associated symptoms, the study team noted. Its approval is based on the results from the COMFORT study, which included only intermediate-2 and high-risk patients, they continued.

“However, intermediate-1 risk patients may carry a significant burden of disease and are increasingly treated with ruxolitinib in the real-life setting. Moreover, in some European countries (e.g., Germany) approval of ruxolitinib is not restricted to higher risk patients but rather to those with symptomatic disease (even when intermediate-1 or low risk),” the authors wrote.

Given the lack of studies investigating the effectiveness and safety of ruxolitinib in an intermediate-1 risk patient population and the small cohorts and short follow-up times used in previous studies, the research team aimed to assess the drug in a real-world clinical practice context.

The retrospective study included data from over 1000 patients with MF who had received ruxolitinib since 2013. Approximately 56% of the patients were intermediate risk-1.

The authors observed a 26% spleen response rate after six months of ruxolitinib in the intermediate risk-1 population and a 68% symptom response rate. Both rates were slightly inferior in patients with intermediate risk-2.

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Hypomethylating Agents Show Promise in Myelofibrosis Progression After alloHCT

Donor chimerism was restored with hypomethylating agent (HMA) treatment among some patients with myelofibrosis (MF) who relapsed after allogeneic hematopoietic cell transplantation (alloHCT), according to a small retrospective published in the journal Transplantation and Cellular Therapy.

These data suggest that HMA “is an option for patients in the future,” the researchers wrote in their report. “By promoting restoration of donor chimerism and clearance of pre-alloHCT somatic mutations, HMAs offer a capable therapeutic strategy for improving outcomes in this challenging patient population.”

In the single-center, retrospective study, the researchers analyzed data from the electronic health records of 12 patients with MF who relapsed after alloHCT between 2020 and 2023 and were subsequently treated with an HMA.

The median age of the cohort was 61 years and 33% of patients had primary MF, 41.7% had post-essential thrombocythemia MF, and 25.0% had post-polycythemia vera MF.

There were 92% of patients with disease classified as intermediate-2/high-risk by the Dynamic International Prognostic Scoring System (DIPSS) and 83% were considered high or very high risk by the Molecular International Prognostic Scoring System (MIPSS70+). There were 66.7%, 25.0%, and 16.7% of patients with JAK2MPL, or CALR driver mutations, respectively, at diagnosis.

After transplantation, 99.9% of patients achieved donor chimerism at day 30 and 96.6% at day 100. Patients relapsed after alloHCT within a median of 282.5 days (range, 96-2388 days). The median donor chimerism before initiating an HMA was 57.82%.

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Shear Wave Elastography Distinguishes Myelofibrosis From Other MPNs

Sep 25, 2024

 

Liver and spleen shear-wave elastography helped distinguish patients with myelofibrosis from healthy controls and those with essential thrombocytopenia, according to findings published in the Journal of Ultrasound. This suggests that the technique may help diagnose myeloproliferative neoplasms.

Researchers added that liver stiffness and spleen stiffness appeared to be linked with bone marrow fibrosis.

“Vibration-controlled transient elastography (VCTE) has proven to be a valuable tool in providing prognostic and staging information in patients with liver disease, greatly reducing the need for liver biopsy,” Vito Sansone, MD, Student, and colleagues wrote. “Spleen stiffness, similarly, has proven useful as a surrogate marker of portal hypertension. To date, however, the role of any of these techniques in the work-up of MPNs has not been established. …This study aims to investigate if values of liver and spleen stiffness measured with shear-wave elastography could help to differentiate MPNs from healthy controls and if there are significant differences in values of liver stiffness and spleen stiffness.”

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New Trial Sets Out to Test Treatment for Early Primary MF

A new randomized, double-blind, placebo-controlled, phase 3 clinical trial assessing the safety and efficacy of ropeginterferon alfa-2b, a new-generation pegylated interferon-based therapy, in patients with early and lower-risk primary myelofibrosis (MF) is now open.

The trial aims to recruit 150 such patients who are at least 18 years of age and will receive either up to 500 μg of subcutaneous ropeginterferon alfa-2b or a placebo every 2 weeks until 56 weeks.

The primary endpoints of the trial include clinically relevant complete hematologic response as measured by platelet count, white blood cell count, hemoglobin levels in peripheral blood, absence of thrombotic events, and no progression to acute myeloid leukemia, and symptom endpoint.

Secondary endpoints include bone marrow response, event-free survival or progression-free survival, molecular response in driver or relevant coexisting gene mutations, and safety.

“The study will provide important data for the treatment of early/lower-risk [primary] MF for which an anti-clonal, disease-modifying agent is highly needed,” the researchers wrote in an article that they published in the journal Annals of Hematology, which contains the details of the trial design.

The trial is not yet recruiting participants. It is estimated to start in October 2024 and be completed in August 2027.

Previous research has shown that ropeginterferon alfa-2b has favorable pharmacokinetics and safety profiles and requires less frequent injections than previous formulations of pegylated interferon alfa, the researchers noted.

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