[Rinsho ketsueki] The Japanese journal of clinical hematology最新文献

Histiocytic sarcoma (HS) is a rare aggressive hematological malignancy reported to occur secondary to B cell lymphoma. We report a case of HS secondary to splenic marginal zone lymphoma (SMZL) complicated by autoimmune hemolytic anemia (AIHA) in a 64-year-old man. He was referred to our department with anemia and was diagnosed as having AIHA. After starting treatment with prednisolone, atypical lymphocytes appeared in his blood tests, and a bone marrow biopsy revealed invasion by B cell lymphoma. A CT scan showed splenomegaly and a pancreatic mass, which confirmed the diagnosis of SMZL. The patient received bendamustine and rituximab as chemotherapy, which rapidly improved the anemia and splenomegaly and reduced atypical lymphocytes. However, left lumbar back pain appeared along with an increase in the pancreatic mass, and he died suddenly of acute renal failure. An autopsy revealed that the tumor had invaded several organs including the pancreas, and immunohistochemistry was positive for CD163, leading to the diagnosis of HS. Furthermore, the specimens of SMZL and HS were positive for IgH gene reconstitution, and exome analysis showed genetic abnormalities in 226 genes including CARD11, suggesting that the SMZL and HS had the same origin.

A 53-year-old woman presented with shortness of breath and hyperleukocytosis and was admitted to our hospital. Shortly after, she went into cardiopulmonary arrest and was resuscitated. Her white blood cell count was 566,000/µl, with 94.5% cup-like blasts positive for MPO staining and FLT3-ITD positive, so she was diagnosed with acute myeloid leukemia (AML) M1. She also had disseminated intravascular coagulation and tumor lysis syndrome. Extracorporeal membrane oxygenation (ECMO) was started to manage bilateral pulmonary thromboembolism that had developed due to deep vein thrombosis, and induction therapy was performed under ECMO. On the third day of illness, the patient developed cerebral hemorrhage. Hematological remission was confirmed on the 39th day of illness. After consolidation therapy with chemotherapy and an FLT3 inhibitor, she underwent allogeneic hematopoietic stem cell transplantation, and remains alive. Case reports suggest strong evidence of mortality benefit from ECMO in patients with hematologic malignancies, particularly when ECMO served as a bridge through chemotherapy. Our patient suffered from cardiopulmonary arrest due to hyperleukocytosis and pulmonary thromboembolism, but was saved by induction of remission under ECMO. Improvements in supportive care should lead to reduction in early deaths during induction therapy.

Many patients with chronic myeloid leukemia (CML) can now maintain response thanks to the advent of tyrosine kinase inhibitors (TKIs) and STAMP inhibitors, but adverse events associated with prolonged TKI therapy have become a problem. Adequate management of adverse events is key to successful treatment, as some can significantly impact the patient's prognosis. The goal of CML treatment was once to prevent acute transformation, but now that many patients achieve deep remission and long-term survival, the goal has shifted to achieving long-term treatment free remission (TFR). It is essential to carefully consider disease risk, patient background, and adverse events of each therapeutic agent in order to make the appropriate choice. This article reviews the treatment of chronic phase CML (CML-CP) as described in the 2023 edition of the Guidelines for Hematopoietic Tumors, focusing on treatment options for first-line CML-CP, dose optimization of ponatinib, outcomes with the new CML drug asciminib, and TFR.

POEMS syndrome is a plasma cell neoplasm that presents with peripheral neuropathy, organomegaly, fluid retention, skin manifestations, osteosclerotic lesions, and λ-type M-proteinemia. The pathogenesis of POEMS syndrome is poorly understood, as the genetic profile of plasma cells in POEMS syndrome differs from that of myeloma. In most cases, POEMS syndrome is difficult to distinguish from chronic inflammatory demyelinating polyneuropathy (CIDP). Consequently, it is essential not to miss characteristic signs of POEMS syndrome such as M-protein, VEGF, pleural effusion, and osteosclerotic lesions. Novel agents for myeloma, such as thalidomide, lenalidomide, and bortezomib, are effective. For younger patients, these agents followed by autologous transplantation with high-dose melphalan is the standard of care. More relapses are now being reported in results of long-term observation, and treatment strategies for relapsed disease must be established.

Adult T-cell leukemia/lymphoma (ATLL) is an aggressive peripheral T-cell malignancy caused by human T-cell leukemia virus type-1 (HTLV-1) infection. Genetic alterations are thought to contribute to the pathogenesis of ATLL alongside HTLV-1 products such as Tax and HBZ. Several large-scale genetic analyses have delineated the entire landscape of somatic alterations in ATLL, which is characterized by frequent alterations in T-cell receptor/NF-κB pathways and immune-related molecules. Notably, up to one-fourth of ATLL patients harbor structural variations disrupting the 3'-UTR of the PD-L1 gene, which facilitate escape of tumor cells from anti-tumor immunity. Among these alterations, PRKCB and IRF4 mutations, PD-L1 amplification, and CDKN2A deletion are associated with poor prognosis in ATLL. More recently, several single-cell transcriptome and immune repertoire analyses have revealed phenotypic features of premalignant cells and tumor heterogeneity as well as virus- and tumor-related changes of the non-malignant hematopoietic pool in ATLL. Here we summarize the current understanding of the molecular pathogenesis of ATLL, focusing on recent progress made by genetic, epigenetic, and single-cell analyses. These findings not only provide a deeper understanding of the molecular pathobiology of ATLL, but also have significant implications for diagnostic and therapeutic strategies.

Diffuse large B-cell lymphoma (DLBCL) accounts for approximately 40% of all malignant lymphomas, making it the most common subtype. Molecular genetic studies have elucidated the pathogenesis of DLBCL and the causes of its poor prognosis. This basic research has led to the development of novel molecularly targeted therapies that target molecules and cellular antigens in relevant signaling pathways or epigenetic enzymes. Treatment with polatuzumab vedotin, rituximab, cyclophosphamide, doxorubicin, and prednisone has become the standard of care for newly diagnosed CD20-positive DLBCL with an International Prognostic Index score of 2 to 5, based on its reported efficacy for this indication. In addition, the development of immunotherapy such as anti-CD19-chimeric antigen receptor (CAR)-T therapy and bispecific antibodies such as epcoritamab, mosunetuzumab, and glofitamab has led to a paradigm shift in treatment of relapsed/refractory DLBCL. This review summarizes the evolution of treatment development for DLBCL, as well as the results of the current clinical standard of care and new therapies that are expected to become the standard of care.

Sustaining lifelong hematopoiesis requires maintenance, proliferation, and differentiation of hematopoietic stem cells. Thrombopoietin is a cytokine essential for regulation of hematopoietic stem cells as well as differentiation and maturation of megakaryocytes required for platelet production. Due to these properties, thrombopoietin agonists have been used to treat bone marrow failure syndromes such as aplastic anemia. Through analysis of thrombopoietin gene-deficient mice, my colleagues and I have demonstrated the mechanism of action of thrombopoietin receptor agonists in hematopoietic stem cell maintenance and differentiation. This review focuses on governance of homeostasis in the hematopoietic system by thrombopoietin signaling.

For nearly 40 years, combination therapy with cytarabine and anthracycline has been the standard of care for acute myeloid leukemia (AML). The cytogenetics and molecular biology of AML are now understood, and the treatment of AML has undergone dramatic changes in Japan with the launch of drugs such as FLT3 inhibitors, Bcl2 inhibitors, and hypomethylating agents since 2018. However, AML remains very difficult to cure, with a high relapse rate. Here, we review novel agents that have not yet been approved in Japan (CPX-351, IDH inhibitors, menin inhibitors, and oral azacitidine) as potential treatments for AML, as well as therapeutic antibodies (BiTEs, DARTs, immune checkpoint inhibitors) currently under investigation in clinical trials or in development. These novel agents are being investigated not only as monotherapy but also as combination therapy with intensive chemotherapy or azacitidine/venetoclax. The new era of AML treatment is expected to support a variety of goals, including leukemic cell elimination, long-term remission, and improved quality of life.

FLT3 mutation is one of the most frequent genetic mutations in AML, identified in approximately 30% of patients, and FLT3-ITD mutation is considered a poor prognostic factor. Based on these molecular and clinical backgrounds, FLT3 mutations are considered promising therapeutic targets in AML, and intensive development of targeted therapeutics has been ongoing for more than two decades. Recently, combination of FLT3 inhibitors with intensive chemotherapy for untreated AML patients with FLT3 mutations and FLT3 inhibitor monotherapy for relapsed/refractory patients have been approved. In Japan, the combination of quizartinib and intensive chemotherapy for untreated FLT3-ITD-positive AML was approved in 2023. Clinical use of FLT3 inhibitors shows strong promise for improving the clinical outcomes of these AML patients with an extremely poor prognosis. Meanwhile, various resistance mechanisms to FLT3 inhibitors have been identified, including the emergence of resistance-associated mutations, and attenuated inhibitory effects of FLT3 inhibitors involving the bone marrow microenvironment surrounding AML cells. Thus, future efforts should aim to optimize combination therapy based on the characteristics of each FLT3 inhibitor, develop biomarkers that could inform treatment selection, and to better understand these resistance mechanisms and develop methods for overcoming them.

Chimeric antigen receptor-transduced autologous T (CAR-T) cell therapy targeting CD19 has revolutionized the treatment of CD19-positive hematological tumors, including acute lymphoblastic leukemia and large B-cell lymphoma. However, despite the high response rate, many problems such as exceedingly high cost, complex logistics, insufficient speed, and manufacturing failures have become apparent. One solution for these problems is to use an allogeneic cell as an effector cell for genetic modification with CAR. Allogeneic, or "off-the-shelf", CAR-expressing immune-effector cells include 1) genome-edited, T-cell receptor (TCR) gene-deleted CAR-T cells generated using healthy adult donor T cells, 2) induced pluripotent stem cell-derived CAR-T cells, and 3) CAR NK cells. NK cells are notorious for their poor ex-vivo expansion and low susceptibility to genetic modification. In this article, I will review the current state and future prospects of allogeneic CAR cell therapies, with special reference to CAR NK cells.