Continuous and differential improvement in worldwide access to hematopoietic cell transplantation: activity has doubled in a decade with a notable increase in unrelated and non-identical related donors

Stem cell transplantation indications for patients with acute leukemia determined by measurable residual disease: what we know and what we do not know

Acute leukemia (AL), which includes acute myeloid leukemia (AML) and acute lymphoblastic leukemia (ALL), is a hematological malignancy characterized by the uncontrolled proliferation of immature myeloid or lymphoid cells. Allogeneic stem cell transplantation (ASCT) remains a therapeutic option for patients with AL. Determination of transplantation indications is a key step in successful ASCT and in curing patients. Currently, the measurable residual disease (MRD) is used as a biomarker for response evaluation, relapse prediction, preemptive therapy, and post-remission treatment selection. In this review, we discuss the advantages and disadvantages of these techniques for MRD detection. We focused mainly on the residual disease-directed selection of transplant indications for patients with either AML or ALL and provided expert opinions in these settings. We also discuss the challenges associated with transplantation indications and propose expert opinions and future directions for the selection of indications for transplantation.

Results of the Latin American Bone Marrow Transplantation Society (LABMT) activity survey 2019-2022: the impact of the COVID-19 pandemic and the increase in related haploidentical donors

A total of 6767 first hematopoietic cell transplants (HCT), 4121 autologous (61%) and 2646 allogeneic (39%), were reported by 166 teams from 12 Latin American countries that answered the 2022 LABMT/WBMT activity survey. The transplant rate (TR) for Latin America in 2022 was 103 HCT/10 million inhabitants with a wide variation between the different countries. The main indication for allogeneic (allo)-HCT was acute lymphoblastic leukaemia (41%) for the pediatric population and acute myeloid leukemia (32%) for adults. The main indication for autologous (auto)-HCT was neuroblastoma (33%) in children and plasma cell disorders (57%) in adults. In alloHCT, the most used hematopoietic cell source was the bone marrow (54%) in pediatric while peripheral blood stem cells (PBSC) (87%) was in adults. PBSC was the source of choice for autoHCT in both ages. The main trends observed in the period 2019-2022 was a decrease in the number of procedures in 2020 in association with the start of the COVID-19 pandemic, resuming growth in the following years. AlloHCT had a greater growth compared to autoHCT, and it was mainly driven by the utilization of haploidentical related donors, which became the main source from 2020 onwards.

The Applications of Machine Learning in the Management of Patients Undergoing Stem Cell Transplantation: Are We Ready?

Hematopoietic stem cell transplantation (HSCT) is a life-saving therapy for hematologic malignancies, such as leukemia and lymphoma and other severe conditions but is associated with significant risks, including graft versus host disease (GVHD), relapse, and treatment-related mortality. The increasing complexity of clinical, genomic, and biomarker data has spurred interest in machine learning (ML), which has emerged as a transformative tool to enhance decision-making and optimize outcomes in HSCT. This review examines the applications of ML in HSCT, focusing on donor selection, conditioning regimen, and prediction of post-transplant outcomes. Machine learning approaches, including decision trees, random forests, and neural networks, have demonstrated potential in improving donor compatibility algorithms, mortality and relapse prediction, and GVHD risk stratification. Integrating "omics" data with ML models has enabled the identification of novel biomarkers and the development of highly accurate predictive tools, supporting personalized treatment strategies. Despite promising advancements, challenges persist, including data standardization, algorithm interpretability, and ethical considerations regarding patient privacy. While ML holds promise for revolutionizing HSCT management, addressing these barriers through multicenter collaborations and regulatory frameworks remains essential for broader clinical adoption. In addition, the potential of ML can cope with some challenges such as data harmonization, patients' data protection, and availability of adequate infrastructure. Future research should prioritize larger datasets, multimodal data integration, and robust validation methods to fully realize ML's transformative potential in HSCT.

Impact of the COVID-19 outbreak on the field of hematopoietic cell transplantation in the Asia-Pacific region: APBMT Activity Survey 2020/2021

COVID-19 became a global pandemic in 2020 and significantly affected the activity of hematopoietic cell transplants (HCT) worldwide. Despite these challenges, a total of 28,793 transplants, including 18,518 allogeneic and 10,275 autologous transplants, were performed in 719 facilities in 2020 in the Asia-Pacific (AP) region. This represented a 5.1% increase in allogeneic transplants and a 3.1% increase in autologous transplants, an overall increase of 4.4% compared to the numbers in 2019. With respect to the donor source, haploidentical transplants increased significantly by 18.6%, related transplants by 8.8%, and cord blood transplants (CBT) by 9.2%. However, the number of unrelated transplants, excluding CBT, decreased for the first time by 8.2%. As a result, COVID-19 facilitated the growth of haploidentical transplants due to cross-border restrictions. Regarding the changes in the total number of transplants by country/region in 2020, it increased by 2,048 transplants in China, followed by Japan (210 transplants) and Korea (230 transplants); however, 14 of the 22 countries and regions decreased their number of transplants in 2020 compared to the previous year. There was no correlation between the increase or decrease in the number of transplants in 2020 and the Gross National Income (GNI) per capita of each country/region in 2020, as well as Domestic General Government Health Expenditure as a percentage of General Government Expenditure (GGHE-D/GGE). In 2021, the total number of transplants in this region was 34,754. With the exception of a few countries/regions that decreased the number of transplants in 2020, most countries/regions have started to see a recovery in 2021. The COVID-19 pandemic significantly affected the supply chain and logistics involved in HCT rather than its numbers; however, we have found ways to overcome logistical challenges to carry out transplant medicine without delay, even under these circumstances.

The role of registries in hematological disorders

Hematopoietic cell transplantation (HCT) was developed more than 65 years ago to treat malignant blood disorders and irreversible bone marrow failures, with the aim of replacing a diseased hematopoietic system with a healthy one (allogeneic HCT). Decades later, the procedure was adapted to apply maximal chemotherapy or radiotherapy, which would result in bone marrow failure, but could be remedied by an infusion of a patient's own cryopreserved bone marrow (autologous HCT). Both treatments are high-risk and complex, especially during the initial phases. However, concerted efforts, vision, and collaboration between physicians and centers worldwide have resulted in HCT becoming a standard of care for many hematological disorders with progressive improvements in outcomes. Registries and the collaboration of societies worldwide have enabled the delivery of this curative therapy to many patients with fatal hematological diseases. More than 1.5 million HCT were performed between 1957 and 2019, and activity is continuously increasing worldwide.