The Use of Allogeneic Hematopoietic Stem Cell Transplantation in Primary Myelofibrosis.

Primary myelofibrosis (PMF) is a BCR-ABL1 negative myeloproliferative neoplasm characterized by clonal proliferation of myeloid cells. This leads to reactive bone marrow fibrosis, ultimately resulting in progressive marrow failure, hepatosplenomegaly, and extramedullary hematopoiesis. PMF is considered the most aggressive of the BCR-ABL1 negative myeloproliferative neoplasms with the least favorable prognosis. Constitutional symptoms are common, which can impact an individual's quality of life and leukemic transformation remains an important cause of death in PMF patients. The development of the Janus kinase 2 (JAK2) inhibitors have provided a good option for management of PMF-related symptoms. Unfortunately, these agents have not been shown to improve overall survival or significantly alter the course of disease. Allogenic hematopoietic stem cell transplantation (allo-HSCT) remains the only curative treatment option in PMF. However, allo-HSCT is associated with significant treatment-related morbidity and mortality and has historically been reserved for younger, high-risk patients. This review examines patient, disease, and transplant-specific factors which may impact transplant-related outcomes in PMF. Through the vast improvements in donor selection, conditioning regimens, and post-transplant care, allo-HSCT may provide a safe and effective curative option for a broader range of PMF patients in the future.

Leveraging Natural Killer Cell Innate Immunity against Hematologic Malignancies: From Stem Cell Transplant to Adoptive Transfer and Beyond.

Numerous recent advancements in T-cell based immunotherapies have revolutionized the treatment of hematologic malignancies. In the race towards the first approved allogeneic cellular therapy product, there is growing interest in utilizing natural killer (NK) cells as a platform for off-the-shelf cellular therapies due to their scalable manufacturing potential, potent anti-tumor efficacy, and superior safety profile. Allogeneic NK cell therapies are now being actively explored in the setting of hematopoietic stem cell transplantation and adoptive transfer. Increasingly sophisticated gene editing techniques have permitted the engineering of chimeric antigen receptors, ectopic cytokine expression, and tumor recognition signals to improve the overall cytotoxicity of NK cell therapies. Furthermore, the enhancement of antibody-dependent cellular cytotoxicity has been achieved through the use of NK cell engagers and combination regimens with monoclonal antibodies that act synergistically with CD16-expressing NK cells. Finally, a greater understanding of NK cell biology and the mechanisms of resistance have allowed the preclinical development of NK checkpoint blockade and methods to modulate the tumor microenvironment, which have been evaluated in early phase trials. This review will discuss the recent clinical advancements in NK cell therapies in hematologic malignancies as well as promising avenues of future research.

The Evolving Landscape of Frontline Therapy in Chronic Phase Chronic Myeloid Leukemia (CML).

PURPOSE OF REVIEW: Chronic myeloid leukemia (CML) is a myeloproliferative neoplasm characterized by uncontrolled proliferation of mature and maturing granulocytes. The disease is characterized by the presence of translocation t(9;22) leading to the abnormal BCR-ABL fusion. Historically, treatment options included hydroxyurea, busulfan, and interferon-α (IFN-α), with allogeneic stem cell transplant being the only potential curative therapy. More recently, the development of tyrosine kinase inhibitors (TKIs) has revolutionized the treatment of CML and turned a once fatal disease into a chronic and manageable disorder. This review aims to discuss the frontline treatment options in chronic-phase CML, provide recommendations for tailoring frontline treatment to the patient, and explore emerging therapies in the field. RECENT FINDINGS: The first-generation TKI, imatinib, was FDA approved in 2001 for use in CML. Following the approval and success of imatinib, second- and third-generation TKIs have been developed providing deeper responses, faster responses, and different toxicity profiles. With numerous options available in the frontline setting, choosing the best initial treatment for each individual patient has become a more complex decision. When choosing a frontline therapy for patients with chronic-phase CML, one should consider disease risk, comorbid conditions, and the goal of therapy.

Applications of Gene Editing Technologies to Cellular Therapies.

Hematologic malignancies are characterized by genetic heterogeneity, making classic gene therapy with a goal of correcting 1 genetic defect ineffective in many of these diseases. Despite initial tribulations, gene therapy, as a field, has grown by leaps and bounds with the recent development of gene editing techniques including zinc finger nucleases, transcription activator-like effector nucleases, and clustered regularly interspaced short palindromic repeat (CRISPR) sequences and CRISPR-associated protein-9 (Cas9) nuclease or CRISPR/Cas9. These novel technologies have been applied to efficiently and specifically modify genetic information in target and effector cells. In particular, CRISPR/Cas9 technology has been applied to various hematologic malignancies and has also been used to modify and improve chimeric antigen receptor-modified T cells for the purpose of providing effective cellular therapies. Although gene editing is in its infancy in malignant hematologic diseases, there is much room for growth and application in the future.

NCCN Guidelines Insights: Myeloproliferative Neoplasms, Version 2.2018.

Myeloproliferative neoplasms (MPNs) are a group of heterogeneous disorders of the hematopoietic system that include myelofibrosis (MF), polycythemia vera (PV), and essential thrombocythemia (ET). PV and ET are characterized by significant thrombohemorrhagic complications and a high risk of transformation to MF and acute myeloid leukemia. The diagnosis and management of PV and ET has evolved since the identification of mutations implicated in their pathogenesis. These NCCN Guideline Insights discuss the recommendations outlined in the NCCN Guidelines for the risk stratification, treatment, and special considerations for the management of PV and ET.

Myeloproliferative Neoplasms, Version 2.2017, NCCN Clinical Practice Guidelines in Oncology.

Myelofibrosis (MF), polycythemia vera (PV), and essential thrombocythemia (ET) are a group of heterogeneous disorders of the hematopoietic system collectively known as Philadelphia chromosome-negative myeloproliferative neoplasms (MPNs). The diagnosis and the management of patients with MPNs have evolved since the identification of mutations that activate the JAK pathway (JAK2, CALR, and MPL mutations) and the development of targeted therapies has resulted in significant improvements in disease-related symptoms and quality of life. This manuscript discusses the recommendations outlined in the NCCN Guidelines for the diagnostic workup of MPN (MF, PV, and ET), risk stratification, treatment, and supportive care strategies for the management of MF.

Clinical potential of elacytarabine in patients with acute myeloid leukemia.

Acute myeloid leukemia (AML) has been treated for over four decades with standard induction chemotherapy including seven days of cytosine arabinoside (cytarabine, ara-C) infusion. Cytarabine, while effective in killing leukemic cells, is subject to development of several resistance mechanisms rendering the drug ineffective in many patients. Elacytarabine, a lipophilic 5'-elaidic acid ester or nucleoside analogue of cytosine arabinoside, was created with the intent of overcoming resistance mechanisms including reduced expression of the human equilibrative nucleoside transporter 1 (hENT1) required for cytarabine entry into cells, as well as increased activity of cytidine deaminase (CDA) which breaks down the active metabolite of cytarabine, ara-CTP. Elacytarabine enters cells independently of transporters, has a longer half life compared with cytarabine and is not subject to deactivation by CDA. Preclinical data were encouraging although subsequent clinical studies have failed to show superiority of elacytarabine compared with standard of care as monotherapy in patients with AML. Clinical trials utilizing elacytarabine in combination with anthracyclines are ongoing. Use of hENT1 expression as a predictive marker for cytarabine or elacytarabine response has been studied with no conclusive validation to date. Despite promising early results, the jury is still out in regards to this novel agent as an effective alternative to standard cytarabine therapy in acute leukemias, especially in combination with additional agents such as anthracyclines.

WT1 vaccination in acute myeloid leukemia: new methods of implementing adoptive immunotherapy.

INTRODUCTION: The Wilms tumor 1 (WT1) gene was originally identified as a tumor suppressor gene that, when mutated, would lead to the development of pediatric renal tumors. More recently, it has been determined that WT1 is overexpressed in 90% of patients with acute myeloid leukemia (AML) and is mutated in approximately 10% of AML patients. WT1 plays a role in normal hematopoiesis and, in AML specifically, it has oncogenic function and plays an important role in cellular proliferation and differentiation. The ubiquity of WT1 in leukemia has lead to the development of vaccines aimed at employing the host immune system to mount a T-cell response to a known antigen. AREAS COVERED: In this evaluation, the authors discuss the role of WT1 in normal hematopoiesis as well as in the development of hematologic malignancies. Furthermore, the authors discuss the data supporting the development of WT1 vaccines, and the clinical trials supporting their use in patients with acute leukemia. EXPERT OPINION: Several small trials have been conducted which support the safety and efficacy of this therapy, although larger trials are certainly warranted. In the authors' opinion, the WT1 vaccination has potential in terms of its application as an adjuvant therapy for patients with AML who are at high risk of relapse or who have detectable minimal residual disease after initial standard therapy.