Parsaclisib Added to Ruxolitinib Decreases Spleen Volume and Improves Symptom Scores in Myelofibrosis

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Kyle Doherty

The PI3Kδ inhibitor parsaclisib added to a stable dose of ruxolitinib (Jakafi) reduced spleen volume and improved symptom scores for patients with myelofibrosis who experienced a suboptimal response to ruxolitinib, according to findings from a phase 2 study (NCT02718300) published in Blood Adv.

Final results of the study revealed that patients who received daily-to-weekly dosing of parsaclisib (n = 32) and those who received all-daily dosing of parsaclisib (n = 42) achieved a decrease in spleen volume of at least 10% at 12 weeks at rates of 28.0% and 59.5%, respectively. Moreover, patients achieved a 50% decrease or more at week 12 in Myelofibrosis Symptom Assessment Form symptom scores at rates of 14% and 28%, respectively; the rates of at least a 50% decrease at week 12 in Myeloproliferative Neoplasms Symptom Assessment Form symptom scores were 18% and 32%, respectively.

“Ruxolitinib reduces spleen volume, improves symptoms, and increases survival in patients with intermediate- or high-risk myelofibrosis. However, suboptimal response may occur, potentially because of signaling via the PI3K/protein kinase B pathway,” Abdulraheem Yacoub, MD, professor of Hematologic Malignancies and Cellular Therapeutics at KU Medical Center in Kansas City, Kansas, and coauthors wrote. “The addition of parsaclisib to stable-dose ruxolitinib can reduce splenomegaly and improve symptoms, with manageable toxicity in patients with myelofibrosis with suboptimal response to ruxolitinib.”

The study authors added that parsaclisib was designed with a different molecular structure than earlier-generation PI3K inhibitors—the orally bioavailable, potent, and highly selective next-generation inhibitor may in turn be able to limit both on- and off-target toxicities that were previously seen.

Additional findings from the study demonstrated that in the overall population evaluable for the primary end point (n = 65), the median change in spleen volume was −163.6 cm3 (range, −735.6 to 10173 cm3), with a median percentage change of −11% (range, −47% to 444%). At week 24, these figures were −192.0 cm3 (range, −2040 to 761.4 cm3) and −10% (range, −89% to 34%) among 49 evaluable patients. The median percentage change was greater among patients who received all-daily dosing compared with those who received daily-to-weekly dosing both at 12 weeks (−15.0% vs −2.0%) and 24 weeks (−19.0% vs −2.5%, respectively).

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Utilization of Momelotinib for Myelofibrosis With Anemia Can Result in Small Savings

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Laura Joszt, MA

Although momelotinib to treat myelofibrosis (MF) with anemia has a higher acquisition cost, it is partially offset by savings when transfusion-related costs are reduced, according to a poster being presented at the AMCP Annual Conference, held April 15-18, 2024, in New Orleans, Louisiana.1

MF is a rare cancer in the bone marrow that disrupts the production of blood cells.2 MF causes anemia because of the extensive scarring to bone marrow. This extensive scarring also causes patients to have a low number of platelets, increasing their risk of bleeding. Patients may also have an enlarged spleen.

Momelotinib inhibits Janus kinase (JAK) 1, JAK2, and activin A receptor type 1. In September 2023, the FDA approved momelotinib to treat patients with intermediate- or high-risk MF with anemia.3

The approval of momelotinib was based on data from the phase 3 MOMENTUM trial, which found clinically significant improvements for patients treated with momelotinib vs danazol.4 A quarter of patients treated with momelotinib had a 50% or greater reduction in total symptom score compared with only 16% of patients on danazol.

Since the approval, the National Comprehensive Cancer Network (NCCN) has added momelotinib5 to its Clinical Practice Guidelines in Oncology for Myeloproliferative Neoplasms. Momelotinib was added as a category 2A treatment for patients with high-risk MF. It was also added as a 2B category treatment for patients with lower-risk MF.

Patients with MF who have anemia and are dependent on transfusions have increased medical costs and poor prognosis, the authors of the AMCP poster noted. JAK inhibitors may provide improvements in symptoms and spleen size, but they could worsen or induce anemia. However, momelotinib has been shown to reduce spleen size.4

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Predictors of clinical outcome in myeloproliferative neoplasm, unclassifiable: A Bone Marrow Pathology Group study

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Genevieve M Crane, MD, PhD; Julia T Geyer, MD; Beenu Thakral, MD; Sa A Wang, MD, Geoffrey D Wool, MD, PhD; Ke David Li, MD; Adam R Davis, MD; Leonardo Boiocchi, MD; David Bosler, MD; Carlos E Bueso-Ramos, MD, PhD

April 10, 2024

Abstract

Objectives

Myeloproliferative neoplasm, unclassifiable (MPN-U, revised to MPN, not otherwise specified in the fifth edition of the World Health Organization classification) is a heterogeneous category of primary marrow disorders with clinical, morphologic, and/or molecular features that preclude classification as a more specific MPN subtype due to stage at diagnosis, overlapping features between MPN subtypes, or the presence of coexisting disorders. Compared with other MPN subtypes, the contribution of the mutational landscape in MPN-U in conjunction with other clinical and morphologic biomarkers to prognosis has been less well investigated.

Methods

We performed a multicenter, retrospective study of MPN-U (94 cases) to better define the clinicopathologic features, genetic landscape, and clinical outcomes, including subgroups of early-stage, advanced-stage, and coexisting disorders. The Dynamic International Prognostic Scoring System (DIPSS) plus scoring system was applied to assess its relevance to MPN-U prognosis.

Results

Multivariate analysis demonstrated bone marrow blast count and DIPSS plus score as statistically significant in predicting overall survival. Univariate analysis identified additional potential poor prognostic markers, including abnormal karyotype and absence of JAK2 mutation. Secondary mutations were frequent in the subset analyzed by next-generation sequencing (26/37 cases, 70.3%) with a borderline association between high molecular risk mutations and overall survival.

Conclusions

This study, as one of the largest of MPN-U studies incorporating both clinicopathologic and molecular data, moves toward identification of biomarkers that better predict prognosis in this heterogeneous category.

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Ryvu Therapeutics Presents Preclinical Data on RVU120 and Synthetic Lethality Programs at the 2024 AACR Annual Meeting

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10 Apr, 2024

  • Ryvu PRMT5 inhibitors show potential best-in-class profiles, including a strong antiproliferative effect on MTAP-deleted cell lines and a good safety window versus MTAP WT cells.
  • Ryvu’s WRN inhibitor program has demonstrated target engagement and selective potency with a synthetic lethal effect; in vivo efficacy studies exhibited pronounced tumor growth inhibition in an MSI-H colorectal cancer xenograft model.
  • Ryvu’s proprietary ONCO Prime discovery platform, which recently received a PLN 26 million (approx. USD 6.6 million) grant from the Polish Agency for Enterprise Development, has identified novel drug targets in KRAS-mutant patient-derived cells (PDCs) with therapeutic potential in colorectal cancer; the ONCO Prime platform has broad potential across multiple tumor types.
  • RVU120 shows efficacy both as a monotherapy and synergistically in combination with ruxolitinib in preclinical models of myeloproliferative neoplasms, including myelofibrosis and polycythemia vera.
  • MEN1703 (SEL24), presented by partner Menarini Group, shows cytotoxic activity in myelofibrosis cell lines as a monotherapy and synergistically in combination with ruxolitinib.

KRAKOW, Poland, April 10, 2024 /PRNewswire/ — Ryvu Therapeutics (WSE: RVU), a clinical-stage drug discovery and development company focusing on novel small molecule therapies that address emerging targets in oncology, presents preclinical data from its synthetic lethality pipeline, RVU120, and MEN1703 (SEL24) at the 2024 AACR Annual Meeting, April 5-10 in San Diego, California.

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Dr. Guo Develops Test Promising Answers for Cancer Patients

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Cancer researcher, Belinda Guo, knows that one of the biggest issues for people with myeloproliferative neoplasms (a group of rare blood cancers), is not knowing if the cancer will progress.

Dr Belinda Guo and her team at the University of Western Australia’s Translational Cancer Pathology Laboratory have invented a new blood-based test that detects specific changes in the blood of patients diagnosed with myelofibrosis.

With funding from Cancer Council WA, they are now working with clinicians to assess the blood of individuals who have undergone a bone marrow transplant to see if the transplant has worked.

We sat down with Belinda to hear more about her research project. Read the full interview below.

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Dr Raajit Rampal Discusses Disease Modification and Emerging Therapies in Polycythemia Vera

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Laura Joszt, MA

Achieving a disease-modifying therapy for polycythemia vera might require adjusting the end points in a study needed for a drug to be approved, said Raajit Rampal, MD, PhD, hematologic oncologist, associate attending physician, Memorial Sloan Kettering Cancer Center.

Transcript

Currently, there are no disease-modifying treatments in polycythemia vera, but it is being explored. What might such a therapy look like?

If we talk about disease modification, the first question is, what do you mean by disease modification? I think, what we would want is for our patients to live the longest and fullest life, free of the symptoms or burdens of their disease. To me, that is the sort of working definition of disease modification. From there, one can try to come up with biological definitions of things like depleting the stem cell, which are important things. But keeping this on a patient level, what we want for our patients [is a life free of disease burden]. How do we think about therapies that address those issues?

Part of it is a regulatory conundrum in the sense that studies have to meet certain end points for drugs to get approved, but the way we study the drugs is relative to the definitions of the end points that make the drugs successful. In many cases, [the end point is asking] are you controlling the hematocrit adequately? That’s one of the major things in polycythemia vera. But in order to really try to get at the question of disease modification, we’ve got to think about changing the end points of our studies to reflect that.

What are the things that are going to best correlate with the idea that you aren’t keeping patients free of the catastrophic consequences of their disease, like blood clots, like [disease] turning into leukemia or myelofibrosis? Are you controlling the patient’s symptoms to an adequate degree? Those are the things that I think are fundamental. But we’ve got to change the end points of our studies to really get at that.

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Follow-Up Needs for Blood Cancer Survivors May Determine Best Type of Provider

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Laura Joszt, MA

For patients with blood cancers, follow-up care consisting of management of psychosocial consequences, promotion of a healthy lifestyle, and disease prevention may be better addressed by primary care physicians (PCPs) than oncologists, according to a study published in Cancer Medicine.

The study, conducted in Germany, found most survivors of blood cancers were receiving care at a university hospital and a minority were actually being care for by community oncologists or PCPs. The researchers evaluated follow-up care received by survivors from the University Hospital of Essen using a questionnaire.

“Given the favorable prognosis of many types of blood cancer, there is a wealth of information about long-term treatment side effects, secondary diseases, and quality of life. How and by whom follow-up care is delivered, however, remains largely unexplored,” the authors noted.

Follow-up can be provided in different ways. In one model, oncologists provide follow-up care related to cancer and general practitioners provide other health care at the same time. In another model, survivors of cancer are transferred to PCPs for continued care. In a more complex model, oncologists and general practitioners have complementary roles.

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New study paves the way for precision drugs to treat blood cancers

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by Tampere University

April 4, 2024

The Janus kinase 2 (JAK2) protein mediates signaling from several cytokine receptors in the regulation of hematopoiesis and immune responses. Somatic mutations in human JAK2 lead to constitutive activation and cytokine-independent signaling and underlie several hematological malignancies from myeloproliferative neoplasms (MPN) to acute leukemia and lymphomas. JAK2 contains an active kinase domain and an inactive pseudokinase domain. Interestingly, pathogenic mutations mainly occur in the regulatory pseudokinase domain.

Due to its critical pathogenic role, JAK2 has become an important therapeutic target. The four currently approved JAK2 inhibitors relieve symptoms but do not heal the patient or affect survival. These drugs target the highly conserved kinase domain and affect both normal and mutated JAK2 and, due to side effects, carry a black box warning that limits their use in elderly, cardiac and cancer patients. The selective inhibition of pathogenic JAK2 is a key pending goal in drug discovery that requires a precise mechanistic understanding of the regulation of JAK2 activation.

“To understand the molecular and structural basis of the physiological and pathogenic activation of JAK2, we used single-molecule microscopy and erythropoietin receptor (EpoR) as a model system.

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A new mouse model highlights the need for better JAK inhibitors in myeloproliferative neoplasms

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Charles E. de Bock

The discovery that the gain of function JAK2 V617F mutation is present in myeloproliferative neoplasms (MPNs) has led to numerous clinical trials assessing the efficacy of JAK inhibitors. Most notably, ruxolitinib, a combined JAK1/2 selective inhibitor, has gained approval in patients with myeolofibrosis (MF), and additional JAK2 inhibitors including fedratinib, pacritinib, and momelotinib also under evaluation for patients with MF. However, while these inhibitors demonstrate some clinical benefit, they do not adequately reduce the mutant clone fraction. 1 , 2 Consequently, a critical question for the field has been whether the lack of a durable response is attributed to either (i) the inability of current JAK inhibitors to completely block the pathway or (ii) the possibility that mutant clones are not entirely dependent on this activated pathway.

To address these two possibilities, a new study from the laboratory of Ross Levine, published in Cancer Discovery,developed an innovative mouse model of Jak2 V617F alone or in combination with Tet2 loss. The novel aspect of this mouse model lies in the ability to control the expression and genetic deletion of Jak2 V617F allele from mutant clones upon development of MPN. To do so, it utilizes two orthogonal site‐specific recombinases which exert precise control over the temporal expression and deletion of the Jak2 V617F allele.

The mouse model uses the well‐established Cre recombinase that recognises short nucleotide target sequences called Lox sites, in conjunction with the relatively new Dre recombinase which recognizes short nucleotide sequences called Rox sites. Importantly, the strategic arrangement and orientation of these sequences can lead to either flipping or deletion of the intervening DNA sequence. In this context, Dre recombinase is employed to initiate the expression of the Jak2 V617F allele. Subsequently, a modified CreER recombinase, translocated to the nucleus upon tamoxifen treatment, can delete the Jak2 V617F allele (Figure 1A). This intricate mouse model provided a powerful tool for comparing the durability of response between JAK inhibitors and the genetic loss of Jak2 V617F in the context of MPNs.

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Childbirth rates in women with myeloproliferative neoplasms

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Anna Ravn Landtblom, Therese M-L Andersson, Anna L. V. Johansson, Frida E. Lundberg, Jan Samuelsson, Magnus Björkholm & Malin Hultcrantz

Abstract

Myeloproliferative neoplasms (MPN) are associated with inferior pregnancy outcome, however, little is known about fertility and childbearing potential in women with MPN. In this study we aimed to describe reproductive patterns, as well as to quantify risk of miscarriage and stillbirth. Women aged 15–44 years with an MPN diagnosis 1973–2018, were identified in Swedish health care registers, and age-matched 1:4 to population controls. We identified 1141 women with MPN and 4564 controls. Women with MPN had a lower rate of childbirth (hazard ratio [HR] with 95% confidence interval was 0.78 (0.68–0.90)). Subgroup analysis showed that the rate was not significantly reduced in essential thrombocythemia, HR 1.02 (0.86–1.22) while the HR was 0.50 (0.33–0.76) in PV and 0.45 (0.28–0.74) in PMF. The risk of miscarriage was not significantly increased before MPN diagnosis, the HR during follow-up after diagnosis was 1.25 (0.89-1.76). Women with MPN were more likely to have had a previous stillbirth. Women with MPN had fewer children at diagnosis, and fewer children in total. In conclusion, the childbirth rate was lower among women with MPN than controls, but not among women with essential thrombocythemia.

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