Blood Research最新文献

Patients with chronic myeloid leukemia (CML) in the chronic phase receiving tyrosine kinase inhibitor (TKI) therapy are expected to have long-term survival outcomes comparable to those of the general population. Many clinical trials have confirmed that some patients sustain molecular responses without continuing TKI therapy. Treatment-free remission (TFR) is a new goal in treating chronic CML. The safety and outcome of TFR were studied in clinical trials after discontinuing imatinib or the second-generation TKIs dasatinib or nilotinib. TFR was safe in approximately 50% of patients who achieved a deep molecular response to TKI therapy. Patients who relapsed after discontinuing TKI responded immediately to the reintroduction of TKI. The mechanism by which TFR increases the success rate still needs to be understood. The hypothesis that the modulation of immune function and targeting of leukemic stem cells could improve the TFR is under investigation. Despite the remaining questions, the TFR has become a routine consideration for clinicians in the practice of molecular remission in patients with CML.

Mastocytosis is a heterogeneous neoplasm characterized by accumulation of neoplastic mast cells in various organs. There are three main types: cutaneous mastocytosis (CM), systemic mastocytosis (SM), and mast cell sarcoma. CM mainly affects children and is confined to the skin, whereas SM affects adults and is characterized by extracutaneous involvement, with or without cutaneous involvement. Most cases of SM have an indolent clinical course; however, some types of SM have aggressive behavior and a poor prognosis. Recent advances in the understanding of the molecular changes in SM have changed the diagnosis and treatment of aggressive and advanced SM subtypes. The International Consensus Classification and World Health Organization refined the diagnostic criteria and classification of SM as a result of accumulation of clinical experience and advances in molecular diagnostics. Somatic mutations in the KIT gene, most frequently KIT D816V, are detected in 90% of patients with SM. Expression of CD30 and any KIT mutation were introduced as minor diagnostic criteria after the introduction of highly sensitive screening methods. SM has a wide spectrum of clinical features, and only a few drugs are effective at treating advanced SM. Currently, the mainstay of SM treatment is limited to the management of chronic symptoms related to release of mast cell mediators. Small-molecule kinase inhibitors targeting the KIT-downstream and KIT-independent pathways were recently approved for treating advanced SM. I describe recent advances in diagnosis of SM, and review the currently available and emerging therapeutic options for SM management.

Myelofibrosis (MF) includes primary MF, post-essential thrombocythemia MF, and post-polycythemia vera MF. MF is a progressive myeloid neoplasm characterized by ineffective clonal hematopoiesis, extramedullary hematopoiesis, a reactive bone marrow environment resulting in reticulin deposition and fibrosis, and a propensity for leukemia transformation. The identification of driver mutations in JAK2, CALR, and MPL has contributed to a better understanding of disease pathogenesis and has led to the development of MF-specific therapies, such as JAK2 inhibitors. Despite the fact that ruxolitinib and fedratinib have been clinically developed and approved, their use is limited due to adverse effects such as anemia and thrombocytopenia. Recently, pacritinib has been approved for a group of thrombocytopenic patients with significant unmet clinical needs. In symptomatic and anemic patients with prior JAK inhibitor exposure, momelotinib was superior to danazol in preventing exacerbation of anemia and in controlling MF-associated signs and symptoms, such as spleen size. Although the development of JAK inhibitors is remarkable, modifying the natural course of the disease remains a priority. Therefore, many novel treatments are currently under clinical development. Agents targeting bromodomain and extra-terminal protein, anti-apoptotic protein Bcl-xL, and phosphatidylinositol-3-kinase delta have been studied in combination with JAK inhibitors. These combinations have been employed in both the frontline and "add-on" approaches. In addition, several agents are being studied as monotherapies for ruxolitinib-resistant or -ineligible patients. We reviewed several new MF treatments in the advanced stages of clinical development and treatment options for cytopenic patients.

Plasmacytoid dendritic cells (pDCs) are type I interferon-producing cells that modulate immune responses. There are two types of pDC neoplasms: 1) mature pDC proliferation (MPDCP) associated with myeloid neoplasm and 2) blastic pDC neoplasm (BPDCN). MPDCP is a clonal expansion of mature pDCs that is predominantly associated with chronic myelomonocytic leukemia. In contrast, BPDCN is a clinically aggressive myeloid malignancy involving the skin, bone marrow, lymphatic organs, and central nervous system. There are various types of skin lesions, ranging from solitary brown or violaceous to disseminated cutaneous lesions, which often spread throughout the body. The expression of CD4, CD56, CD123, and pDC markers (TCL-1, TCF4, CD303, and CD304, etc.) are typical immunophenotype of BPDCN. Historically, BPDCN treatment has been based on acute leukemia regimens and allogeneic hematopoietic cell transplantation in selected patients. Recent advances in molecular biology and genetics have led to the development of targeted agents, such as tagraxofusp (a recombinant fusion protein targeting CD123), anti-CD123 CAR-T cells, XmAb14045, and IMGN632. Lastly, this review provides a comprehensive overview of pDC neoplasms.

The treatment outcomes of chronic myeloid leukemia in chronic phase (CML-CP) have dramatically improved with comparable life-expectancy to average of general population in tyrosine kinase inhibitor (TKI) era. However, less than a half of patients who started with TKI can remain on frontline TKI. The reasons of switching TKI can be either intolerance or the lack of efficacy. Although a kinase domain (KD) mutation can guide to select salvage TKI from the point of view on the efficacy of TKIs, many factors need to be considered before choosing next-line TKI such as the high-risk features of CML, the adverse events with prior TKI, and the comorbidities of patients. The therapeutic options for CML-CP after failing frontline TKI due to treatment failure or suboptimal responses will be reviewed including allogeneic hematopoietic stem cell transplantation.

Increasing knowledge of the molecular features of myeloproliferative neoplasms (MPNs) is being combined with existing prognostic models based on clinical, laboratory, and cytogenetic information. Mutation-enhanced international prognostic systems (MIPSS) for polycythemia vera (PV) and essential thrombocythemia (ET) have improved prognostic assessments. In the case of overt primary myelofibrosis (PMF), the MIPSS70 and its later revisions (MIPSS70+ and MIPSS70+ version 2.0) effectively predicted the overall survival (OS) of patients. Because post-PV and post-ET myelofibrosis have different biological and clinical courses compared to overt PMF, the myelofibrosis secondary to PV and ET-prognostic model was developed. Although these molecular-inspired prognostic models need to be further validated in future studies, they are expected to improve the prognostic power in patients with MPNs in the molecular era. Efforts are being made to predict survival after the use of specific drugs or allogeneic hematopoietic stem cell transplantation. These treatment outcome prediction models enable the establishment of personalized treatment strategies, thereby improving the OS of patients with MPNs.

Transfusion is an essential life-sustaining treatment for many patients. However, unnecessary transfusion has been reported to be related to worse patient outcomes. Further, owing to the recent pandemic, blood supply has been more challenging to maintain. Many studies have been conducted to elucidate the optimal transfusion threshold for many clinical conditions, and most suggested that a restrictive transfusion strategy has advantages over a liberal transfusion strategy. Hematologic disorders, which require chronic transfusion in many cases, have not been the main subjects of such studies, and only little evidence is available regarding the optimal transfusion threshold in these patients. According to several recent studies, a liberal transfusion strategy is preferable for patients with hematologic disorders due to their quality of life. A patient-centered approach is needed for proper management of hematologic disorders.

Owing to donor-related issues, blood shortages and transfusion-related adverse reactions have become global issues of grave concern. In vitro manufactured red blood cells (RBCs) are promising substitutes for blood donation. In the United Kingdom, a clinical trial for allogeneic mini transfusion of cultured RBCs derived from primary hematopoietic stem cells has recently begun. However, current production quantities are limited and need improved before clinical use. New methods to enhance manufacturing efficiencies have been explored, including different cell sources, bioreactors, and 3-dimensional (3D) materials; however, further research is required. In this review, we discuss various cell sources for blood cell production, recent advances in bioreactor manufacturing processes, and the clinical applications of cultured blood.