JAB-8263 Monotherapy Demonstrates Early Promise in Myelofibrosis

December 13, 2024

Author(s): Kristi Rosa

The investigative BET inhibitor JAB-8263 was found to be well tolerated and to demonstrate preliminary efficacy in patients with myelofibrosis, according to data from a phase 1/2 study (NCT04686682) presented during the 2024 ASH Annual Meeting.1

Any treatment-emergent adverse effects (TEAEs) occurred in 93.8% of those who received the agent at any dose level (n = 16), with 37.5% experiencing grade 3 or higher TEAEs and 25.0% experiencing a serious TEAEs. Treatment-related AEs (TRAEs) occurred in 87.5% of patients, with 31.3% experiencing grade 3 or higher TRAEs, and 18.8% experiencing serious TRAEs. TRAEs led to dose interruption and reduction for 43.8% and 25.0% of patients, respectively. One patient experienced a TRAE that led to discontinuation of JAB-8263. No treatment-related events proved to be fatal.

Notably, 1 dose-limiting toxicity occurred in a patient who received the agent at a dose of 0.4 mg; this patient experienced grade 3 increases in alanine and aspartate aminotransferase levels.

In all evaluable patients (n = 13), the mean spleen volume reduction (SVR) was –19.95% (range, –39.4% to 3.6%) at week 24 and –26.16% (range, 56.6% to –11.0%) at best response. Notably, 2 patients achieved an SVR of 35% or higher, and 1 patient experienced an SVR of –34.9%. Moreover, at week 24, 60% of 10 patients had a tumor symptom score reduction of at least 50% (TSS50). Two of 8 patients who had received JAK inhibitors experienced a best response of SVR of –41.2% and 34.9%, respectively. Moreover, 50% of 6 evaluable patients who had received JAK inhibitors achieved TSS50 at week 24.

“JAB-8263 at 0.125 mg [once daily to] 0.3 mg [once daily] was well tolerated…Hematological and gastrointestinal AEs are mild with JAB-8263 continuous dosing [compared with] other BET inhibitors,” Junyuan Qi, MD, of the Institute of Hematology and Blood Disease Hospital, Chinese Academy of Medical Sciences, in Tianjin, China, and coauthors, wrote in the poster of the data. “The preliminary efficacy data in myelofibrosis for JAB-8263 monotherapy is promising. Most patients showed spleen reduction and TSS reduction.”

The early-phase study enrolled patients with confirmed primary myelofibrosis (PMF), post–polycythemia vera myelofibrosis (PV-MF), or post–essential thrombocytopenia myelofibrosis (ET-MF). Patients were at least 18 years of age, had spleen volume of at least 450 cm3, a Dynamic International Prognostic Score (DIPSS) of at least intermediate-1, and an ECOG performance status up to 2.

The median age in the 16 total patients was 62 years (range, 36-69) and 56.3% were female. All patients were Asian. Regarding ECOG performance status, 31.3% had a status of 0, 62.5% had a status of 1, and 6.3% had a status of 2. Regarding disease subtype, 68.8% of patients had PMF, 18.8% had PV-MF, and 12.5% had ET-MF. Half of patients had prior exposure to a JAK inhibitor. Most patients had a JAK2 mutation (93.8%). Regarding DIPSS, 68.8% had intermediate-1 disease and 25.0% had intermediate-2 disease. The median time since initial diagnosis was 13.5 months (range, 0.9-76.6).

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Ruxolitinib Plus Pegylated Interferon Alfa-2a Show Promise in Newly Diagnosed Polycythemia Vera

November 1, 2024

Author(s): Alexandra Gerlach, Associate Editor

Ruxolitinib (Jakafi; Incyte Corp) in combination with pegylated interferon alfa-2a demonstrated efficacy and tolerability in patients with newly diagnosed polycythemia vera (PV). According to the 2-year end-of-study results from the phase 2 COMBI 2 clinical trial (EudraCT2018-004150-13), the treatment improved cell counts, bone marrow cellularity, and fibrosis in patients with PV.1

In the phase 2 COMBI 2 trial, researchers evaluated the safety and efficacy of ruxolitinib and low-dose peg-IFN-α2a in patients with newly diagnosed PV.

Image Credit: © MdBabul – stock.adobe.com

PV is a chronic, progressive myeloproliferative neoplasm characterized by the overproduction of red blood cells. The excess cells thicken the blood, slowing its flow and contributing to serious complications, such as blood clots. Almost all patients with PV have the JAK2V617F mutations, and the JAK2V617F variant allele frequency (VAF) is key for determining outcomes, including thrombosis and progression to myelofibrosis.2-4

Ruxolitinib is a Janus kinase inhibitor approved by the FDA in 2011 and is indicated for the treatment of patients with high-risk MF with reduced abnormal expression of PF4, which can lead to decreased fibrosis. It is additionally indicated as a second-line treatment of PV for patients who have an inadequate response to or cannot tolerate hydroxyurea. In the COMBI 2 trial, researchers assessed the efficacy of ruxolitinib in combination with pegylated interferon alfa-2a (peg-IFN-α2a) (Pegasys ProClick; Genentech), an injection commonly used to treat hepatitis B and C infections. According to data from prior studies, peg-IFN-α2a has been shown to induce durable hematologic and molecular remissions in patients with PV. However, approximately 20% to 40% of patients are intolerant or show limited response to peg-IFN-α2a.5-8

In the phase 2 COMBI 2 trial, researchers evaluated the safety and efficacy of ruxolitinib and low-dose peg-IFN-α2a in patients with newly diagnosed PV in an effort to counterbalance intolerance to peg-IFN-α2a. The primary end point was safety, with secondary end points including efficacy, based on hematologic parameters, quality-of-life measurements, and JAK2V617F variant allele frequency (VAF).8

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Ajax Therapeutics Announces First Patient Dosed in Phase 1 Clinical Trial Evaluating AJ1-11095, a First-in-Class Type II JAK2 inhibitor, for the Treatment of Myelofibrosis

October 30, 2024

– AJ1-11095 is the first Type II JAK2 Inhibitor to enter the clinic –

– Preclinically, AJ1-11095 has demonstrated superior efficacy to Type I JAK2 inhibitors, such as ruxolitinib, with disease modifying effects on mutant allele burden and fibrosis –

NEW YORK & CAMBRIDGE, Mass.–(BUSINESS WIRE)–Ajax Therapeutics, Inc., a biopharmaceutical company developing next generation JAK inhibitors for patients with myeloproliferative neoplasms (MPNs), today announced the first patient has been dosed in its Phase 1 clinical trial evaluating AJ1‑11095, a first-in-class Type II JAK2 inhibitor, for the treatment of patients with myelofibrosis.

“We’re excited to announce dosing of the first patient enrolled in our first-in-human study with AJ1-11095” said David Steensma, MD, FACP, Chief Medical Officer at Ajax. “As a first-in-class therapy with a unique mechanism of action as a Type II inhibitor of JAK2, AJ1-11095 was developed to provide a much-needed new treatment for patients with myeloproliferative neoplasms by offering the potential for improved efficacy compared to existing therapies.”

AJ1-11095 is the first JAK2 inhibitor to enter the clinic that binds the Type II conformation of the JAK2 kinase as opposed to all the other approved JAK2 inhibitors, including ruxolitinib, that bind the Type I conformation. The advancement of AJ1-11095 into this Phase 1 clinical trial was based on preclinical studies in which AJ1-11095 showed superior efficacy when compared to Type I JAK2 inhibitors with significant disease modifying effects on mutant allele burden and fibrosis, two of the main hallmarks of myelofibrosis.

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INCA033989 May Address Need for Disease-Modifying Therapies in Myelofibrosis

October 25, 2024

Author(s): Courtney Flaherty

Fact checked by: Megan Hollasch

Unlike the array of JAK inhibitors available for the treatment of patients with myelofibrosis, the novel monoclonal antibody INCA033989 may have disease-modifying potential among those expressing CALR type 1 mutations, potentially addressing an area of need in myeloproliferative neoplasm (MPN) management, according to Daniel J. DeAngelo MD, PhD.

“With the 4 [FDA-approved] JAK inhibitors, we see clear improvements in symptoms, reduction in spleen [volume], and decreased counts for patients with polycythemia or essential thrombocytopenia, but we’re not seeing eradication and normalization of the bone marrow,” DeAngelo said in an interview with OncLive®. “We don’t know if this agent is going to change that, but the hypothesis is that [INCA033989] may be getting at the heart of the disease, although only for patients with CALR type 1 mutations.”

In engineered cell lines and primary CD34-positive cells from patients with MPN, INCA033989 was shown to antagonize mutant CALR–driven signaling and cellular proliferation. Moreover, in a mouse model of MPN with mutant CALR, administration of an INCA033989 mouse surrogate antibody prevented the development of thrombocytosis and accumulation of platelet-producing megakaryocytes in the bone marrow. The agent’s disease-modifying potential is supported by its reduction of pathogenic self-renewal among MPN cells expressing CALR mutations in both primary and secondary transplantations.1

These preclinical data support the agent’s ongoing investigation in a phase 1 study (NCT06034002) for patients with MPN.2

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Recognizing Symptoms of Myeloproliferative Neoplasms and Clinical Trial Challenges

October 24, 2024

Author(s): Mary Caffrey, Laura Joszt, MA

The symptoms of myeloproliferative neoplasms can be variable and common, which can make it difficult to diagnose if you aren’t looking for the right thing, said Ruben Mesa, MD, FACP, executive director of Atrium Health Wake Forest Baptist Comprehensive Cancer Center and president of Atrium Health Levine Cancer.

He also discusses the challenges with getting patients enrolled in clinical trials, such as the limited availability of them and patient factors that make it difficult to participate.

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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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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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Phase 3 Trial of Bomedemstat in Essential Thrombocythemia Begins Enrollment

By Sabrina Serani
Fact checked by Jordyn Sava

A pivotal phase 3 trial (NCT06456346) has initiated to evaluate bomedemstat (MK-3543; IMG-7289), an investigational agent for the treatment of patients with essential thrombocythemia (ET) who have previously not received cytoreductive therapy.1

“The standard of care in essential thrombocythemia has remained unchanged for decades, and patients are in need of new options that have the potential to not only improve disease control, but also improve their quality of life,” said Gregory Lubiniecki, MD, vice president, global clinical development, Merck Research Laboratories, in a press release. “We are rapidly advancing our clinical development programs with the goal of helping to address these unmet needs and bring more options to patients living with myeloproliferative neoplasms.”

The Shorespan-007 trial will compare the orally available LSD1 inhibitor bomedemstat with standard-of-care hydroxyurea in patients with treatment-naive ET, the most common myeloproliferative neoplasm. LSD1 is an enzyme that is potentially important for regulating the proliferation of hematopoietic stem cells, as well as the maturation of progenitor cells.

The study’s primary end point is durable clinicohematologic response rate, and secondary end points include duration of hematologic remission, event-free survival, incidence of adverse events, and disease progression rate. Additionally, investigators will be patient-reported outcomes, including fatigue and symptoms.

The FDA previously granted orphan drug and fast track designations to bomedemstat in ET and myelofibrosis, as well as orphan drug designation in acute myeloid leukemia.

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Dr Grunwald on the Patient Population and Limitations of the REVEAL Study in PV

September 4, 2024

Author(s): Michael R. Grunwald, MD, FACP

Michael R. Grunwald, MD, FACP, hematologist/oncologist, chief, Leukemia Division; director, Transplantation and Cellular Therapy Program, Levine Cancer Institute, Atrium Health, discusses the key characteristics of patients with polycythemia vera (PV) enrolled onto the real-world, observational REVEAL study (NCT02252159), as well as thelimitations of the investigation.

This observational study represents the largest prospective cohort study of patients with PV conducted to date, Grunwald begins. Patients were not uniformly enrolled at the time of diagnosis; rather, they could be enrolled at any stage of their disease progression. A total of 2510 patients were included in the study, with 2023 having a confirmed diagnosis of PV, ensuring the accuracy of their inclusion in the study, he explains. The remaining patients may or may not have had PV, which introduces a level of uncertainty regarding their inclusion, Grunwald adds.

The analysis focused those who exhibited signs of progression to myelofibrosis, he continues. By comparing the characteristics of patients in the transformed group with those in the non-transformed group, it was observed that patients in the transformed group had a longer duration between their initial diagnosis and enrollment in the study, Grunwald elucidates.

Although the study offers valuable insights, it has limitations, according to Grunwald. Although its findings are effective in generating hypotheses, they do not provide definitive guidance on therapeutic interventions, he explains. Real-world data can offer insights into the outcomes of patients with low-risk disease treated with various therapies, Grunwald says. However, the true validation of a therapy’s effectiveness, particularly for low-risk disease, lies in clinical trials, Grunwald reports.

Looking ahead, there is a need for clinical trials that focus on early intervention in patients classified as low risk, who may harbor features indicating a higher risk of disease progression, he continues. Early intervention may alter the disease course, though this must be balanced against the risk of introducing toxicity prematurely or exhausting treatment options too early, Grunwald says. Fortunately, the treatment paradigm for myeloproliferative neoplasms is evolving, with a significant increase in drug development and approvals over the past decade, he notes. It is anticipated that concerns about exhausting treatment options prematurely will diminish as more therapies become available for patients, he concludes.

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Essential Thrombocythemia Trial Launched Evaluating Bomedemstat

By Alex Biese
Fact checked by Ashley Chan

A second phase 3 clinical trial has been launched for the investigational oral drug bomedemstat as a potential new treatment for patients with essential thrombocythemia.

The Shorespan-007 clinical trial, according to a news release from bomedemstat manufacturer Merck, will investigate the use of the drug among patients with essential thrombocythemia who have not previously received cytoreductive therapy.

The global trial, which is currently recruiting, will compare bomedemstat to the current standard of care chemotherapy, hydroxyurea. The trial, with 300 participants, is expected to be concluded in May 2029, according to its listing on clinicaltrials.gov.

Essential thrombocythemia, part of a group of blood cancers known as myeloproliferative neoplasms (MPNs), is a rare disease in which the bone marrow produces too many platelets, according to The Leukemia & Lymphoma Society. This disease, The Leukemia & Lymphoma Society explained, can cause blood clots to form in a patient’s blood vessels, in turn resulting in serious health issues such as stroke, heart attack or pulmonary embolism.

“The standard of care in essential thrombocythemia has remained unchanged for decades, and patients are in need of new options that have the potential to not only improve disease control but also improve their quality of life,” said Dr. Gregory Lubiniecki, vice president of global clinical development for Merck Research Laboratories, in the company’s news release. “We are rapidly advancing our clinical development programs with the goal of helping to address these unmet needs and bring more options to patients living with myeloproliferative neoplasms.”

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