Long-term results of a phase II trial of lenalidomide plus prednisone therapy for patients with myelofibrosis

The role of corticosteroids in the current treatment paradigm for myelofibrosis

INTRODUCTION

Myelofibrosis (MF) is a clonal hematological disorder characterized by bone marrow fibrosis, splenomegaly, and inflammatory cytokine dysregulation. While the role of steroids in MF is not fully defined, their anti-inflammatory properties may offer therapeutic benefits, particularly in managing anemia and other cytopenias. Steroids exert their effects by suppressing pro-inflammatory cytokines such as IL1, IL6, and TNF, and by enhancing anti-inflammatory cytokines like IL4 and IL10. Elevated levels of IL6 and other cytokines in MF are associated with anemia and poor prognosis, suggesting that steroid therapy could mitigate these effects.

AREAS COVERED

In this manuscript, we review clinical studies which evaluated the safety and efficacy of steroids in MF patients. Moreover, we examine clinical data of the combination of steroids with immunomodulatory agents and JAK inhibitors. Our literature search consisted of an extensive review of PubMed and clinicaltrials.gov.

EXPERT OPINION

The role of steroids in the management of MF remains poorly defined, though emerging evidence suggests a potential therapeutic benefit, particularly in managing anemia and other cytopenias. The combination with IMIDs has also yielded positive outcomes as demonstrated in several studies. Steroids may also play a crucial role in managing cytopenias in MF patients receiving JAKi.

Myeloproliferative Neoplasms, Version 3.2022, NCCN Clinical Practice Guidelines in Oncology

The classic Philadelphia chromosome-negative myeloproliferative neoplasms (MPN) consist of myelofibrosis, polycythemia vera, and essential thrombocythemia and are a heterogeneous group of clonal blood disorders characterized by an overproduction of blood cells. The NCCN Clinical Practice Guidelines in Oncology (NCCN Guidelines) for MPN were developed as a result of meetings convened by a multidisciplinary panel with expertise in MPN, with the goal of providing recommendations for the management of MPN in adults. The Guidelines include recommendations for the diagnostic workup, risk stratification, treatment, and supportive care strategies for the management of myelofibrosis, polycythemia vera, and essential thrombocythemia. Assessment of symptoms at baseline and monitoring of symptom status during the course of treatment is recommended for all patients. This article focuses on the recommendations as outlined in the NCCN Guidelines for the diagnosis of MPN and the risk stratification, management, and supportive care relevant to MF.

Novel Therapies in Myelofibrosis: Beyond JAK Inhibitors

PURPOSE OF REVIEW

To discuss the current treatment paradigm, review novel targets, and summarize completed and ongoing clinical trials that may lead to a paradigm shifts in the management of myelofibrosis (MF).

RECENT FINDINGS

In addition to the recent approval and ongoing late-stage development of multiple novel JAK inhibitors, recent clinical studies demonstrate therapeutic potential of targeting multiple alternate proteins and pathways including BET, MDM2, telomerase, BCL2, LSD1, PI3K, SMAC, and PTX2 in patients with MF. MF is a myeloproliferative neoplasm characterized by clonal proliferation of myeloid cells and bone marrow fibrosis often causing cytopenias, extramedullary hematopoiesis resulting in hepatosplenomegaly, and increased pro-inflammatory cytokine production driving systemic symptoms. A significant proportion of morbidity and mortality is related to the propensity to transform to acute leukemia. Allogeneic hematopoietic stem cell transplantation is the only curative therapy; however, due to the high associated mortality, this treatment is not an option for the majority of patients with MF. Currently, there are three targeted Food and Drug Administration (FDA)-approved therapies for MF which include ruxolitinib, fedratinib, and pacritinib, all part of the JAK inhibitor class. Many patients are unable to tolerate, do not respond, or develop resistance to existing therapies, leaving a large unmet medical need. In this review, we discuss the current treatment paradigm and novel therapies in development for the treatment of MF. We review the scientific rationale of each targeted pathway. We summarize updated clinical data and ongoing trials that may lead to FDA approval of these agents.

NK Cells in Myeloproliferative Neoplasms (MPN)

Simple Summary

NK cells are important innate immune effectors that contribute substantially to tumor control, however the role of NK cells in haematological cancers is not as well understood. The aim of this review is to highlight the importance of the role of NK cells in the management of Ph+ Myeloproliferative Neoplasms, and emphasize the need and possible benefits of a more in-depth investigation into their role in classical MPNs and show potential strategies to harness the anti-tumoral capacities of NK cells.

Abstract

Myeloproliferative neoplasms (MPNs) comprise a heterogenous group of hematologic neoplasms which are divided into Philadelphia positive (Ph+), and Philadelphia negative (Ph−) or classical MPNs. A variety of immunological factors including inflammatory, as well as immunomodulatory processes, closely interact with the disease phenotypes in MPNs. NK cells are important innate immune effectors and substantially contribute to tumor control. Changes to the absolute and proportionate numbers of NK cell, as well as phenotypical and functional alterations are seen in MPNs. In addition to the disease itself, a variety of therapeutic options in MPNs may modify NK cell characteristics. Reports of suppressive effects of MPN treatment strategies on NK cell activity have led to intensive investigations into the respective compounds, to elucidate the possible negative effects of MPN therapy on control of the leukemic clones. We hereby review the available literature on NK cells in Ph+ and Ph− MPNs and summarize today’s knowledge on disease-related alterations in this cell compartment with particular focus on known therapy-associated changes. Furthermore, we critically evaluate conflicting data with possible implications for future projects. We also aim to highlight the relevance of full NK cell functionality for disease control in MPNs and the importance of considering specific changes related to therapy in order to avoid suppressive effects on immune surveillance.

JAK Be Nimble: Reviewing the Development of JAK Inhibitors and JAK Inhibitor Combinations for Special Populations of Patients with Myelofibrosis

Myelofibrosis (MF) is a myeloproliferative neoplasm hallmarked by uncontrolled blood counts, constitutional symptoms, extramedullary hematopoiesis, and an increased risk of developing acute myeloid leukemia. Janus kinase (JAK) inhibitors are the most common treatment for MF due to their ability to reduce spleen size and improve disease-related symptoms; however, JAK inhibitors are not suitable for every patient and their impact on MF is limited in several respects. Novel JAK inhibitors and JAK inhibitor combinations are emerging that aim to enhance the treatment landscape, providing deeper responses to a broader population of patients with the continued hope of providing disease modification and improving long-term outcomes. In this review, we highlight several specific areas of unmet need within MF. Subsequently, we review agents that target those areas of unmet need, focusing specifically on the JAK inhibitors, momelotinib, pacritinib, itacitinib, and NS-018 as well as JAK inhibitor combination approaches using CPI-0610, navitoclax, parsaclisib, and luspatercept.

Cancer therapies based on targeted protein degradation - lessons learned with lenalidomide

For decades, anticancer targeted therapies have been designed to inhibit kinases or other enzyme classes and have profoundly benefited many patients. However, novel approaches are required to target transcription factors, scaffolding proteins and other proteins central to cancer biology that typically lack catalytic activity and have remained mostly recalcitrant to drug development. The selective degradation of target proteins is an attractive approach to expand the druggable proteome, and the selective oestrogen receptor degrader fulvestrant served as an early example of this concept. Following a long and tragic history in the clinic, the immunomodulatory imide drug (IMiD) thalidomide was discovered to exert its therapeutic activity via a novel and unexpected mechanism of action: targeting proteins to an E3 ubiquitin ligase for subsequent proteasomal degradation. This discovery has paralleled and directly catalysed myriad breakthroughs in drug development, leading to the rapid maturation of generalizable chemical platforms for the targeted degradation of previously undruggable proteins. Decades of clinical experience have established front-line roles for thalidomide analogues, including lenalidomide and pomalidomide, in the treatment of haematological malignancies. With a new generation of 'degrader' drugs currently in development, this experience provides crucial insights into class-wide features of degraders, including a unique pharmacology, mechanisms of resistance and emerging therapeutic opportunities. Herein, we review these past experiences and discuss their application in the clinical development of novel degrader therapies.

Immunotherapy and Immunomodulation in Myeloproliferative Neoplasms

Myeloproliferative neoplasms are characterized by chronic inflammation. The discovery of constitutively active JAK-STAT signaling associated with driver mutations has led to clinical and translational breakthroughs. Insights into the other pathways and novel factors of potential importance are being actively investigated. Various classes of agents with immunomodulating or immunosuppressive properties have been used with varying degrees of success in treating myeloproliferative neoplasms. Early clinical trials are investigating the feasibility, effectiveness, and safety of immune checkpoint inhibitors, cell-based immunotherapies, and SMAC mimetics. The dynamic landscape of immunotherapy and immunomodulation in myeloproliferative neoplasms is the topic of the present review.

Myeloproliferative Neoplasms: Emerging Treatment Options for Myelofibrosis

Myelofibrosis (MF) is a symptom-forward disease, and its treatment focuses on alleviating those symptoms, as well as improving survival. An initial disease risk assessment is critical for deciding on a course of therapy (and a number of models can be used depending on the available patient information), and anemia can be considered a special case within the treatment algorithms for MF. JAK-STAT inhibition is currently the cornerstone of treatment for MF, but these inhibitors are not perfect. Future research will focus on the microenvironment in reversing fibrosis, immunotherapies, proliferative signaling pathways, epigenetic regulators, and stem cells.

The Rationale for Immunotherapy in Myeloproliferative Neoplasms

PURPOSE OF REVIEW

The classic, chronic Philadelphia chromosome negative myeloproliferative neoplasms (MPN)-essential thrombocythemia (ET), polycythemia vera (PV), and myelofibrosis (MF)-are clonal malignancies of hematopoietic stem cells and are associated with myeloproliferation, organomegaly, and constitutional symptoms. Expanding knowledge that chronic inflammation and a dysregulated immune system are central to the pathogenesis and progression of MPNs serves as a driving force for the development of agents affecting the immune system as therapy for MPN. This review describes the rationale and potential impact of anti-inflammatory, immunomodulatory, and targeted agents in MPNs.

RECENT FINDINGS

The advances in molecular insights, especially the discovery of the Janus kinase 2 (JAK2) V617F mutation and its role in JAK-STAT pathway dysregulation, led to the development of the JAK inhibitor ruxolitinib, which currently represents the cornerstone of medical therapy in MF and hydroxyurea-resistant/intolerant PV. However, there remain significant unmet needs in the treatment of these patients, and many agents continue to be investigated. Novel, more selective JAK inhibitors might offer reduced myelosuppression or even improvement of blood counts. The recent approval of a novel, long-acting interferon for PV patients in Europe, might eventually lead to its broader clinical use in all MPNs. Targeted immunotherapy involving monoclonal antibodies, checkpoint inhibitors, or therapeutic vaccines against selected MPN epitopes could further enhance tumor-specific immune responses. Immunotherapeutic approaches are expanding and hopefully will extend the therapeutic armamentarium in patients with myeloproliferative neoplasms.

Treatment of MDS/MPN and the MDS/MPN IWG International Trial: ABNL MARRO

PURPOSE OF REVIEW

MDS/MPNs comprise a group of rare hematologic malignancies that balance features of myeloproliferation and bone marrow failure. Given overlapping clinical features and rarity of incidence, MDS/MPNs have long posed a diagnostic and therapeutic challenge. Herein, we sought to review recent advances in diagnosis and emerging therapeutic strategies and highlight the upcoming ABNL MARRO study which aims to individualize therapy for patients with MDS/MPN.

RECENT FINDINGS

Focused study of molecular mutations in MDS/MPNs has provided improved diagnostic clarity. Specific gene mutation or patterns of mutation have been increasingly described and have helped to distinguish between clinically similar diseases. While the current treatment landscape consists largely of therapies that have been co-opted from related disease, the emergence of prospective clinical trials specifically focused on MDS/MPN and the increased use of targeted agents represent progress for patients with MDS/MPN. An improved understanding of the molecular drivers of myeloid diseases has provided diagnostic clarity and renewed hope of targeted therapies for MDS/MPN patients. The upcoming ABNL MARRO study hopes to leverage this knowledge to match patients with targeted therapeutic options specific to molecular drivers of their disease.

Pharmacotherapy of Myelofibrosis

Myelofibrosis (MF) is a myeloproliferative neoplasm that is pathologically characterized by bone marrow myeloproliferation, reticulin and collagen fibrosis, and extramedullary hematopoiesis. Constitutive activation of the Janus associated kinase (JAK)-signal transducers and activators of transcription signaling pathway with resultant elevation in pro-inflammatory cytokine levels is the pathogenic hallmark of MF. JAK inhibitors, namely ruxolitinib, have been successful in alleviating symptoms and reducing splenomegaly, but therapy-related myelosuppression has led to the further development of highly selective JAK2 inhibitors. Additionally, ruxolitinib does not appear to affect the malignant hematopoietic clone substantially, evidenced by lack of molecular remissions, bone marrow histopathologic responses, and a proportion of treated patients developing progressive disease and leukemic transformation while receiving therapy. A number of other pharmacotherapeutic strategies are currently being explored in the clinic. Non-JAK inhibitor strategies being evaluated in MF include non-JAK signaling pathway inhibitors, epigenetic-directed therapies, immune-modulating agents, anti-fibrotic agents, and telomerase inhibitors. This review highlights the current landscape of MF pharmacotherapy and explores therapeutic advances underway.

Management of Myelofibrosis-Related Cytopenias

PURPOSE OF REVIEW

Cytopenias, particularly anemia, are frequently encountered in patients with myelofibrosis. Management of cytopenias in myelofibrosis can be very challenging because current therapeutic interventions are only of modest efficacy and ruxolitinib, the only approved drug for myelofibrosis, is myelosuppressive. Yet, dose optimization of ruxolitinib is important for its survival benefit in patients with advanced disease. We sought to summarize the data on treatments for cytopenias available at present and review promising agents in development and emerging strategies.

RECENT FINDINGS

The activin receptor ligand traps hold considerable promise for the treatment of anemia and could represent an attractive combination strategy with ruxolitinib. Low-dose thalidomide, which could offset both anemia and thrombocytopenia caused by ruxolitinib, represents another potential partner for ruxolitinib. The anti-fibrotic agent PRM-151 produced sustained improvements in cytopenias in some patients, and further data on this drug are eagerly awaited. Finally, several preclinical leads with translational potential are worthy of clinical investigation as strategies to halt/reverse bone marrow fibrosis and thereby improve cytopenias. Cytopenias remain a significant hurdle in myelofibrosis management, but several novel investigational agents hold considerable promise for the future.

Treatment of Myelofibrosis: Old and New Strategies

Myelofibrosis (MF) is a BCR-ABL1-negative myeloproliferative neoplasm that is mainly characterised by reactive bone marrow fibrosis, extramedullary haematopoiesis, anaemia, hepatosplenomegaly, constitutional symptoms, leukaemic progression, and shortened survival. As such, this malignancy is still orphan of curative treatments; indeed, the only treatment that has a clearly demonstrated impact on disease progression is allogeneic haematopoietic stem cell transplantation, but only a minority of patients are eligible for such intensive therapy. However, more recently, the discovery of JAK2 mutations has also led to the development of small-molecule JAK1/2 inhibitors, the first of which, ruxolitinib, has been approved for the treatment of MF in the United States and Europe. In this article, we report on old and new therapeutic strategies that proved effective in early preclinical and clinical trials, and subsequently in the daily clinical practice, for patients with MF, particularly concerning the topics of anaemia, splenomegaly, iron overload, and allogeneic stem cell transplantation.

Myelofibrosis: an update on drug therapy in 2016

INTRODUCTION

Primary myelofibrosis (PMF) is the least common but the most aggressive of the classic Philadelphia chromosome-negative myeloproliferative neoplasms. Survival is much shorter in PMF than in polycythemia vera (PV) or essential thrombocythemia (ET). Post-PV/ET myelofibrosis (MF) is clinically indistinguishable from PMF and approached similarly. Areas covered: Current pharmacologic therapy of MF revolves around the Janus kinase 1/2 (JAK1/2) inhibitor ruxolitinib, which dramatically improves constitutional symptoms and splenomegaly in the majority of patients, and improves overall survival (OS). However, allogeneic stem cell transplantation remains the only potential cure. Other JAK inhibitors continue to be developed for MF, and momelotinib and pacritinib are in phase III clinical trials. Anemia is common in MF, and initially worsened by ruxolitinib. Momelotinib and pacritinib may prove advantageous in this regard. Current strategies for managing anemia of MF include danazol, immunomodulatory drugs and erythroid stimulating agents, either alone or in combination with ruxolitinib. Expert opinion: A number of other agents, representing diverse drug classes, are in various stages of development for MF. These include newer JAK inhibitors, other signaling inhibitors, epigenetic modifiers, anti-fibrotic agents, telomerase inhibitors, and activin receptor ligand traps (for anemia). Hopefully, these novel therapies will further extend the clinical benefits of ruxolitinib.

Myeloproliferative Neoplasms: Molecular Drivers and Therapeutics

Activating mutations in genes that drive neoplastic cell growth are numerous and widespread in cancer, and specific genetic alterations are associated with certain types of cancer. For example, classic myeloproliferative neoplasms (MPNs) are hematopoietic stem cell disorders that affect cells of the myeloid lineage, including erythrocytes, platelets, and granulocytes. An activating mutation in the JAK2 tyrosine kinase is prevalent in these diseases. In MPN patients that lack such a mutation, other genetic changes that lead to activation of the JAK2 signaling pathway are present, indicating deregulation of JAK2 signaling plays an etiological driving role in MPNs, a concept supported by significant evidence from in vivo experimental MPN systems. Thus, small molecules that inhibit JAK2 activity are ideal drugs to impede the progression of disease in MPN patients. However, even though JAK inhibitors provide significant symptomatic relief, they have failed as a remission-inducing therapy. Nonetheless, the progress made understanding the molecular etiology of MPNs since 2005 is significant and has provided insight for the development and testing of novel molecular targeted therapeutic approaches. The current understanding of driver mutations in MPNs and an overview of current and potential therapeutic strategies for MPN patients will be discussed.