Dr Scandura on the SENTRY-2 Trial of Single-Agent Selinexor in JAK Inhibitor–Naive Myelofibrosis

October 16, 2024

Author(s): Joe Scandura, MD, PhD

Fact checked by: Ryan Scott, Courtney Flaherty

Joseph M. Scandura, MD, PhD, associate attending physician, NewYork-Presbyterian Hospital; associate professor, medicine, Weill Cornell Medical College, Cornell University, discusses the phase 2 SENTRY-2 study (XPORT-MF-044; NCT05980806) evaluating single-agent selinexor (Xpovio) in JAK inhibitor–naive myelofibrosis.

The FDA granted fast track designation to single-agent selinexor for the treatment of patients with primary myelofibrosis, post-essential thrombocythemia myelofibrosis, and post-polycythemia vera myelofibrosis in July 2023. Notably, selinexor will be assessed in combination with ruxolitinib (Jakafi) in the phase 3 portion of the SENTRY trial (NCT04562389) and as a monotherapy in the phase 2 SENTRY-2 study for JAK inhibitor–naive patients.

The primary aim of the SENTRY-2 study is to evaluate the efficacy of selinexor as a standalone treatment for patients with myelofibrosis who have not previously been treated with a JAK inhibitor, Scandura begins. Currently, JAK inhibitors are the only FDA-approved class of drugs for this condition, complicating the ability to test alternative treatments like selinexor independently, he states. However, evidence suggests that selinexor demonstrates activity, prompting the FDA to permit the study’s initiation, Scandura says. In SENTRY-2, patients will start treatment with selinexor, and responses will be measured based on spleen volume reduction and symptom improvement, particularly anemia, he details.

An innovative aspect of the study is its flexibility, Scandura notes. If a patient shows some degree of response but it is not deemed significant, they may have a JAK inhibitor added to their treatment regimen, he explains. This could include ruxolitinib or newer agents such as pacritinib (Vonjoy), which does not suppress platelet counts, making it suitable for patients with low platelets. Momelotinib (Ojjaara), known for its efficacy in improving anemia, will be added if patients are anemic and maintain adequate platelet counts.

The importance of safety and rigorous science is emphasized in clinical trials, especially when evaluating new treatments, Scandura continues. With selinexor already recognized as safe, the focus shifts to optimizing its use in the treatment landscape of myelofibrosis, he says. If selinexor gains FDA approval for myelofibrosis, it could play a significant role in a more nuanced treatment approach, reflecting the complexities of managing this condition amidst financial considerations and the availability of multiple JAK inhibitors, Scandura concludes.

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Pacritinib Demonstrates Efficacy, Tolerability in Patients with Myelofibrosis and Thrombocytopenia

October 16, 2024

Author(s): Alexandra Gerlach, Associate Editor

Pacritinib (Vonjo; CTI BioPharma Corp) demonstrated improved spleen volume reduction (SVR) and was tolerable in patients with myelofibrosis (MF) and thrombocytopenia, according to data published in the European Journal of Hematology. The findings offer deeper insights into the capabilities of Janus kinase (JAK) inhibitors to improve SVR and overall survival (OS), contradicting prior studies advising against use of JAK inhibitors for thrombocytopenia.1

Further studies are needed to identify the long-term safety and efficacy of the therapy.

Image Credit: © AkuAku – stock.adobe.com

Thrombocytopenia, a condition that occurs when blood platelet counts are too low, is a disease-related feature of MF that leads to poorer prognoses impacting both OS and leukemia-free survival. It can be caused by a variety of factors including ineffective hematopoiesis, splenic sequestration, and treatment-related effects. Allogeneic hematopoietic stem cell transplantation (HSCT) remains the only curable treatment for MF but is only available for a minority of patients. However, the development of JAK inhibitors has expanded treatment options for patients with MF and may show promise for treatment of thrombocytopenia.2

Pacritinib is a JAK inhibitor used to treat intermediate or high-risk MF that targets JAK2 and FMS-like tyrosine kinase 3. It was approved by the FDA in 2022 for treatment of both primary and secondary MF in patients with platelet counts < 50 x 109/L. In the phase 3, randomized, controlled PERSIST-2 trial (NCT02055781), pacritinib demonstrated favorable efficacy and tolerability compared with best available therapy (BAT) in patients with MF and thrombocytopenia.3-5

In the study, approximately 300 patients with thrombocytopenia and primary or secondary myelofibrosis were randomized in a 1:1:1 ratio to receive either pacritinib 400 mg once daily, pacritinib 200 mg twice daily, or BAT. The primary end points included SVR of ≥ 35% reduction in spleen volume from baseline to week 24 as measured by MRI or computed tomography, as well as ≥ 50% reduction in the total symptom score from baseline to week 24 on the Myeloproliferative Neoplasm Symptom Assessment Form 2.0.1,5

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Dr Klisovic on a Case Discussion of Momelotinib in Myelofibrosis With Anemia

October 16, 2024

Author(s): Rebecca Klisovic, MD

Fact checked by: Ashling Wahner, Ryan Scott

Rebecca Klisovic, MD, chief medical information officer, University Hospitals Seidman Cancer Center, discusses 3 case studies about patients with myelofibrosis that were presented during an OncLive® State of the Science Summit™ on hematologic oncology, which she chaired.

The first case that was discussed was on a 71-year-old male patient with newly diagnosed myelofibrosis with splenomegaly, mild anemia, a high symptom burden, and intermediate-2–risk disease, Klisovic begins. The consensus among the panelists was that this patient required treatment due to his spleen size, symptoms, and anemia, she says. Although some oncologists who participated in the discussion considered using ruxolitinib (Jakafi) because of its early survival data, the panel predominantly favored momelotinib (Ojjaara), given this agent’s potential benefit in patients with anemia, she explains.

The second case was on a 62-year-old female patient with myelofibrosis who had already received ruxolitinib and had comorbidities including symptom scoring and a large spleen, according to Klisovic. This patient also had anemia, with a hemoglobin level of 7.2 g/dL, she reports. Therefore, the focus on improving anemia made momelotinib a clear treatment choice in this setting, she adds. Whereas other case presentations prompted treatment debates between the panelists, this case was more clear cut, especially since this patient was refractory to ruxolitinib, Klisovic emphasizes.

The third case was on a 54-year-old female patient with newly diagnosed myelofibrosis that was characterized by both anemia and thrombocytopenia, as well as a platelet count of 34/µL, Klisovic says. This discussion centered around the use of pacritinib vs momelotinib, informed by the patient’s low platelet count, she explains. Some discussants raised concerns about the patient’s eligibility for momelotinib clinical trials, which have enrollment criteria with varying platelet cutoffs, she notes. Despite these concerns, most participants favored the use of pacritinib (Vonjo) due to this agent’s efficacy in managing thrombocytopenia, she reports. However, some discussants noted that momelotinib could also be a viable treatment option for patients similar to the one in this case, depending on clinical trial criteria and individual patient factors, she concludes.

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Luspatercept Shows Promise in Alleviating Myelofibrosis-Associated Anemia

Luspatercept shows promise in alleviating myelofibrosis-associated anemia and has a safety profile consistent with previous research, according to a study published in Blood Advances. 

The most common therapeutics in myelofibrosis include erythropoiesis-stimulating agents, androgens, corticosteroids, and lenalidomide. However, many of these are associated with significant adverse events (AEs). Researchers are investigating therapeutic agents that are highly effective against anemia while having an acceptable safety profile.

Luspatercept is an erythropoietin maturation agent that has been approved in the United States for treating anemia in some individuals with myelodysplastic syndromes or beta-thalassemia who need red blood cell (RBC) transfusion. This therapeutic has been shown to induce transfusion independence in approximately 38% of patients. Researchers sought to explore if the success of luspatercept can be replicated in myelofibrosis and conducted a study to assess its use in patients with myelofibrosis-associated anemia, with or without transfusion dependence.

Researchers reported results from a phase 2, multicenter, open-label trial that assessed the use of luspatercept in myelofibrosis. They recruited adult patients with myeloproliferative neoplasm (MPN)-associated myelofibrosis who possessed an Eastern Cooperative Oncology Group performance status score of 2 or less and had evidence of anemia. Patients were divided according to their transfusion dependence status and whether they were on ruxolitinib therapy.

Participants received subcutaneous luspatercept at a dose of 1.0 mg/kg (with titration up to 1.75 mg/kg every 21 days for a total of 24 weeks). They were then assessed for their disease response at day 169; if they demonstrated clinical benefits, they could continue receiving luspatercept treatment for approximately 2 years longer. The primary endpoint of this study was anemia response at the end of the 24-week period.

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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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