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

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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Dr. Guo Develops Test Promising Answers for Cancer Patients

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

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

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

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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Emerging Data Continue to Evolve Treatment Utilization in MPNs

Laura Joszt, MA

Emerging data are continually changing the knowledge base around how interferons should be used, despite being around for decades, in patients with myeloproliferative neoplasms (MPNs), says Raajit Rampal, MD, PhD, hematologic oncologist, associate attending physician, Memorial Sloan Kettering Cancer Center.

Transcript

How has the landscape for MPN treatment evolved since the introduction of interferons? How does it look different today?

I guess it’s more a question of utilization than the landscape, in the sense that both things like hydroxyurea and interferons and drugs, like an anagrelide for ET [essential thrombocythemia], have been around for quite some time. And I think that it hasn’t been clear for the majority of that time which drugs should be used when and by whom.

There is now randomized clinical trial data for pegylated interferon vs hydroxyurea, but more recently, particularly with regards to polycythemia vera, there’s randomized data with ropeginterferon and hydroxyurea. And at least in that data set, the [blood] count control was superior with ropeginterferon vs hydroxyurea over the course of a number of years. Initially, at 1 year, there wasn’t so much of a difference, but as time went on, there was clearly a difference that favored the use of ropeginterferon in terms of controlling the blood counts. Similarly, over time, there does seem to be a decrease in the JAK [Janus kinase] 2 mutation burden in the patients who got the ropeginterferon.

I think that there is an emerging data set that is arguing that there are benefits to interferon. Going back to the initial point here, the landscape has changed to some degree—with the introduction of something like ropeginterferon—but I think it’s more that the data is evolving, which is beginning to tell us maybe which drugs might be best for which patients. We’re not completely there by any stretch of the imagination, but the data is beginning to coalesce around the message.

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Retrospective Study Shows HSCT Consolidation After Blast Reduction Improves OS in Chronic Phase–Reverted MPN

Ashling Wahner

Patients with myeloproliferative neoplasms in accelerated or blast phase (MPN-AP/BP) who revert to chronic phase (cMPN) after blast-reduction therapy, as well as those with complete response (CR) or CR with incomplete hematologic recovery (CRi) after blast reduction, experience improved overall survival (OS) outcomes after hematopoietic stem cell transplant (HSCT) consolidation therapy, according to findings from a single-center, retrospective analysis evaluating outcomes with intensive and nonintensive blast-reduction strategies in patients with MPN-AP/BP, which were published in Blood Advances.1

This study, which used clinically relatable response criteria developed at the Princess Margaret Cancer Centre, as well as the European LeukemiaNet (ELN) 2022 acute myeloid leukemia (AML) response criteria, found that patients who received intensive blast-reduction therapy achieved a best overall response rate (ORR) of 77% (n = 62/81) vs 39% (n = 21/54) in those who received nonintensive therapy. CR/CRi and cMPN reversions were observed in 24 and 38 patients in the intensive group and 4 and 17 patients in the nonintensive group, respectively.

Although allogeneic HSCT is the only therapy associated with long-term survival improvements for patients with MPN-AP/BP, this treatment strategy is typically reserved for patients who have achieved disease control. Other blast-reduction strategies include induction chemotherapy, as well as hypomethylating agents (HMAs)—such as azacitidine (Vidaza)—as monotherapy or in combination with agents such as venetoclax (Venclexta).2

“However, the optimal blast-reduction strategy and depth of disease clearance required before HSCT are unknown,” lead study author Marta B. Davidson, MD, PhD, FRCPC, of the Princess Margaret Cancer Centre in Toronto, Ontario, Canada, and coauthors, wrote in the paper.1 “Moreover, a lack of standardized response criteria to evaluate the treatment of MPN-AP/BP poses challenges for understanding treatment efficacy between reported studies.”

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Pegylated Interferons Have Promise but Also Unmet Potential in MPNs

Jared Kaltwasser

Pegylated interferons are a meaningful therapeutic option for the treatment of myeloproliferative neoplasms (MPNs), but a new review article says more research is needed to better understand the ideal usage of the therapy.

The report was published in Therapeutic Advances in Hematology.

Study investigators said several interferon products are currently available to treat patients with MPNs, but they said the short half-life of interferons and the risk of (AEs) effects have limited their usage. Pegylation can help overcome those issues, they said.

“Many of these shortcomings were addressed by covalently binding polyethylene glycol to the interferon structure, which increases the stability, prolongs activity, and reduces immunogenicity of the molecule,” the authors wrote.

More research is needed to better understand when and in whom pegylate interferon therapy is most effective | Image Credit: Iamnee – stock.adobe.com

They said current National Comprehensive Cancer Network guidelines call for pegylated interferons to be used for polycythemia vera (PV), essential thrombocythemia (ET), and primary myelofibrosis (PMF). Currently, there are 2 pegylated interferons available for patients with MPNs, they said: peginterferon alfa-2a (Pegasys; pharma&) and ropeginterferon alfa-2b-njft (BESREMi; PharmaEssentia). Both medications are recommended as cytoreductive therapies for PV, the investigators said.

Dr Raajit Rampal Highlights Emerging Therapies in MPNs

March 22, 2024

By Laura Joszt, MA

Interferons have been used for decades to treat myeloproliferative neoplasms (MPNs), and new emerging therapies, such as the Janus kinase (JAK) inhibitor ruxolitinib, are expanding the therapeutic armamentarium, said Raajit Rampal, MD, PhD, hematologic oncologist, associate attending physician, Memorial Sloan Kettering Cancer Center.

What is the importance of interferons as a treatment for MPNs, and what role do they play?

Interferons have been used now for decades in MPNs, and they demonstrate clinical efficacy, certainly in essential thrombocytopenia, in polycythemia vera, and there is data for prefibrotic myelofibrosis.1 Now there are a number of different interferons. There were interferons that were given 3 times a week, and pegylated interferon, which is what we use most often, and now there’s ropeginterferon, which is every 2 weeks as a treatment.

What the interferons can do, for sure, is that they can reduce blood counts. So, for people with the polycythemia or with essential thrombocytopenia, we can get a reduction in the blood counts in the majority of patients. What is also interesting is that—and as has been known now for a number of years—the allele burden, particularly of JAK2, can decrease over time with the treatment with interferons, which at least would suggest to us that you may be depleting part of the clone that causes the disease. So, there are certainly a number of important clinical benefits of interferons, but even potentially biological effects.

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The Role of DNA Repair (XPC, XPD, XPF, and XPG) Gene Polymorphisms in the Development of Myeloproliferative Neoplasms

by , , , , , and  

Abstract

Background and Objectives: Several polymorphisms have been described in various DNA repair genes. Nucleotide excision DNA repair (NER) detects defects of DNA molecules and corrects them to restore genome integrity. We hypothesized that the XPCXPDXPF, and XPG gene polymorphisms influence the appearance of myeloproliferative neoplasms (MPNs). Materials and Methods: We investigated the XPC 1496C>T (rs2228000, XPC Ala499Val), XPC 2920A>C (rs228001, XPC Lys939Gln), XPD 2251A>C (rs13181, XPD Lys751Gln), XPF-673C>T (rs3136038), XPF 11985A>G (rs254942), and XPG 3507G>C (rs17655, XPG Asp1104His) polymorphisms by polymerase chain reaction–restriction fragment length polymorphism analysis in 393 MPN patients [153 with polycythemia vera (PV), 201 with essential thrombocythemia (ET), and 39 with primary myelofibrosis (PMF)] and 323 healthy controls. Results: Overall, we found that variant genotypes of XPD 2251A>C were associated with an increased risk of MPN (OR = 1.54, 95% CI = 1.15–2.08, p = 0.004), while XPF-673C>T and XPF 11985A>G were associated with a decreased risk of developing MPN (OR = 0.56, 95% CI = 0.42–0.76, p < 0.001; and OR = 0.26, 95% CI = 0.19–0.37, p < 0.001, respectively). Conclusions: In light of our findings, XPD 2251A>C polymorphism was associated with the risk of developing MPN and XPF-673C>T and XPF 11985A>G single nucleotide polymorphisms (SNPs) may have a protective role for MPN, while XPC 1496C>T, XPC 2920A>C, and XPG 3507G>C polymorphisms do not represent risk factors in MPN development.