Page 38 - Haematologica May 2022

D. Niederwieser et al.
ABSTRACT
The Worldwide Network of Blood and Marrow Transplantation (WBMT) pursues the mission of promoting hematopoietic cell transplantation (HCT) for instance by evaluating activities through member societies, national registries and individual centers. In 2016, 82,718 first HCT were report- ed by 1,662 HCT teams in 86 of the 195 World Health Organization member states representing a global increase of 6.2% in autologous HCT and 7.0% in allogeneic HCT and bringing the total to 1,298,897 pro- cedures. Assuming a frequency of 84,000/year, 1.5 million HCT were performed by 2019 since 1957. Slightly more autologous (53.5%) than allogeneic and more related (53.6%) than unrelated HCT were reported. A remarkable increase was noted in haploidentical related HCT for leukemias and lymphopro- liferative diseases, but even more in non-malignant diseases. Transplant rates (TR; HCT/10 million pop- ulation) varied according to region reaching 560.8 in North America, 438.5 in Europe, 76.7 in Latin America, 53.6 in South East Asia/Western Pacific (SEA/WPR) and 27.8 in African/East Mediterranean (AFR/EMR). Interestingly, haploidentical TR amounted to 32% in SEA/WPR and 26% in Latin America, but only 14% in Europe and EMR and 4.9% in North America of all allogeneic HCT. HCT team density (teams/10 million population) was highest in Europe (7.7) followed by North America (6.0), SEA/WPR (1.9), Latin America (1.6) and AFR/EMR (0.4). HCT are increasing steadily worldwide with narrowing gaps between regions and greater increase in allogeneic compared to autologous activity. While related HCT is rising, largely due to increase in haploidentical HCT, unrelated HCT is plateauing and cord blood HCT is in decline.
Introduction
Allogeneic and autologous hematopoietic stem cell transplantation (HCT) is considered a routine but com- plex therapy for patients with otherwise incurable chemo- and immune-sensitive malignant and non-malig- nant disorders.1 The treatment is also used for replacing deficient hematopoietic cells or cellular components and more recently for repairing hematopoietic stem cells by gene editing. Despite its increasing applications and inter- national expansion of access, allogeneic HCT is still asso- ciated with significant morbidity and mortality and remains an example of highly specialized, high-cost med- icine. It requires extensive experience, significant infra- structure and a network of specialists from all fields of medicine. Over the last two decades in particular, allo- geneic HCT has undergone a constant technological evo- lution, with decreasing transplant related-morbidity and mortality and expansion of the donor pool. This has been achieved by optimizing indications, by manipulating alloreactive immune reactions ex vivo and in vivo and by using novel reduced or minimal intensity conditioning regimens.2 As a result, HCT is being offered to patients without a matched donor, to older patients and to those with comorbidities.3-5 The predominant autologous HCT transplant type, in contrast, relies exclusively on the high- dose preparative regimen for tumor eradication or for reshaping the immune system in autoimmune diseases.6,7 Patients’ own hematopoietic stem cells are required to rebuild a normal hematopoietic system after the intensive preparative regimen. Missing graft-versus-host disease leads to extremely low mortality, but missing graft-versus- tumor effects to high relapse rates. It is not surprising that autologous HCT involves different treatment strategies and indications as compared to allogeneic HCT, but like allogeneic HCT it requires extensive experience, signifi- cant infrastructure and a network of specialists from all fields of medicine.
However, the increasing specialization and complexity of health care systems required, threaten global equity of access to HCT. The World Health Organization (WHO;
www.who.org) declared the transplantation of organs, cells and tissues a global priority and formed a task force to address quality, safety and equity of access. In order to achieve this, analysis of baseline global activity and evolving trends is essential.8 The Worldwide Network for Blood and Marrow Transplantation (WBMT; www.wbmt.org), is a non-governmental (NGO) umbrella organization in the field of HCT and in collaboration with the WHO, has taken up the challenge of collecting and disseminating global HCT activity data on a regular basis. Information on indications, the use of different technologies, donor types and trends over time provide a sound basis for physicians to provide appropriate patient counseling and for health care agencies to develop the necessary infrastructure. Informed by global activity sur- vey data, the WBMT performs worldwide workshops to support the development of new HCT programs and to optimize existing programs. The ability to share accumu- lated experience covering a wide range of strategies, suc- cesses and pitfalls continues to be key in improving global HCT access for patients in need.
The first WBMT HCT activity report was based on the global HCT activity in 2006.8 This was followed by an updated report in 2010.9 After reaching the global mile- stone of one million HCT in 2012,10 the WBMT focused on analyzing major trends from 2006 onwards11 and noted a narrowing of gaps in the African/East Mediterranean (AFR/EMRO) regions.12
The success of HCT depends on a number of factors including, the early and effective control of the underlying disease prior to HCT, risk of relapse of the underlying dis- ease and donor characteristics. Over the past decade, the rapid evolution of molecular diagnostic and prognostic techniques has led to the emergence of more accurate prognostic tools and effective targeted molecular therapies for malignant hematological diseases.
We report on the global activity trends between 2014 and 2016 compared to 2006 with a specific focus on global trends in equity of access, in indications of HCT and in donor type.
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