Special issues related to hematopoietic SCT in the Eastern Mediterranean region and the first regional activity report

An Analysis of the Worldwide Utilization of Hematopoietic Stem Cell Transplantation for Acute Myeloid Leukemia

Acute myeloid leukemia (AML) has an aggressive course and a historically dismal prognosis. For many patients, hematopoietic stem cell transplantation (HSCT) represents the best option for cure, but access, utilization, and health inequities on a global scale remain poorly elucidated. We wanted to describe patterns of global HSCT use in AML for a better understanding of global access, practices, and unmet needs internationally. Estimates of AML incident cases in 2016 were obtained from the Global Burden of Disease 2019 study. HSCT activities were collected from 2009 to 2016 by the Worldwide Network for Blood and Marrow Transplantation through its member organizations. The primary endpoint was global and regional use (number of HSCT) and utilization of HSCT (number of HSCT/number of incident cases) for AML. Secondary outcomes included trends from 2009 to 2016 in donor type, stem cell source, and remission status at time of HSCT. Global AML incidence has steadily increased, from 102,000 (95% uncertainty interval: 90,200-108,000) in 2009 to 118,000 (104,000-126,000) in 2016 (16.2%). Over the same period, a 54.9% increase from 9659 to 14,965 HSCT/yr was observed globally, driven by an increase in allogeneic (64.9%) with a reduction in autologous (-34.9%) HSCT. Although the highest numbers of HSCT continue to be performed in high-resource regions, the largest increases were seen in resource-constrained regions (94.6% in Africa/East Mediterranean Region [AFR/EMR]; 34.7% in America-Nord Region [AMR-N]). HSCT utilization was skewed toward high-resource regions (in 2016: AMR-N 18.4%, Europe [EUR] 17.9%, South-East Asia/Western Pacific Region [SEAR/WPR] 11.7%, America-South Region [AMR-S] 4.5%, and AFR/EMR 2.8%). For patients <70 years of age, this difference in utilization was widened; AMR-N had the highest allogeneic utilization rate, increasing from 2009 to 2016 (30.6% to 39.9%) with continued low utilization observed in AFR/EMR (1.7% to 2.9%) and AMR-S (3.5% to 5.4%). Across all regions, total HSCT for AML in first complete remission (CR1) increased (from 44.1% to 59.0%). Patterns of donor stem cell source from related versus unrelated donors varied widely by geographic region. SEAR/WPR had a 130.2% increase in related donors from 2009 to 2016, and >95% HSCT donors in AFR/EMR were related; in comparison, AMR-N and EUR have a predilection for unrelated HSCT. Globally, the allogeneic HSCT stem cell source was predominantly peripheral blood (69.7% of total HSCT in 2009 increased to 78.6% in 2016). Autologous HSCT decreased in all regions from 2009 to 2016 except in SEAR/WPR (18.9%). HSCT remains a central curative treatment modality in AML. Allogeneic HSCT for AML is rising globally, but there are marked variations in regional utilization and practices, including types of graft source. Resource-constrained regions have the largest growth in HSCT use, but utilization rates remain low, with a predilection for familial-related donor sources and are typically offered in CR1. Further studies are necessary to elucidate the reasons, including economic factors, to understand and address these health inequalities and improve discrepancies in use of HSCT as a potentially curative treatment globally.

Strategic priorities for hematopoietic stem cell transplantation in the EMRO region

The World Health Organization-designated Eastern Mediterranean region (EMRO) consists of 22 countries in North Africa and Western Asia with a collective population of over 679 million. The area comprises some of the wealthiest countries per capita income and some of the poorest. The population structure is also unique and contrasts with western countries, with a much younger population. The region sits in the heart of the thalassemia belt. Many countries have a significant prevalence of sickle cell disease, and cancer is on the rise in the region. Therefore, the strategic priorities for the growth and development of hematopoietic stem cell transplantation (HSCT) differ from country to country based on resources, healthcare challenges, and prevalent infrastructure. Thirty-one reporting teams to the Eastern Mediterranean Blood and Marrow Transplantation Group have active HSCT programs in 12 countries; allogeneic transplants outnumber autologous transplants, and the proportion of allotransplants for non-malignant conditions is higher in the EMRO region than in Western Europe and North America. The vast majority (99%) of allotransplants are from matched related donors. Matched unrelated donors and other alternate donor transplants are underutilized. The chance of finding a matched related donor for allografts is higher, with a significant chance of finding matched donors among non-sibling related donors. Reasons for relatively lower rates of transplants compared with other countries are multifactorial. Capacity building, development of newer centers, innovative funding, and better utilization of information technology are required to make transplantation as an accessible modality to more patients. Cost-effectiveness and cost-containment, regulation, and ensuring quality will all be priorities in planning HSCT development in the region.

Special issues related to the diagnosis and management of acquired aplastic anemia in countries with restricted resources, a report on behalf of the Eastern Mediterranean blood and marrow transplantation (EMBMT) group and severe aplastic anemia working party of the European Society for blood and marrow transplantation (SAAWP of EBMT)

Aplastic anemia is a relatively rare but potentially fatal disorder, with a reported higher incidence in developing countries in comparison to the West. There are significant variations in epidemiological as well as etiological factors of bone marrow failure syndromes in the developing countries in comparison to the developed world. Furthermore, the management of bone marrow failure syndromes in resource constraint settings has significant challenges including delayed diagnosis and referral, limited accessibility to healthcare facilities, treatment modalities as well as limitations related to patients who require allogeneic stem cell transplantation. Here we will provide a review of the available evidence related to specific issues of aplastic anemia in the developing countries and we summarize suggested recommendations from the Eastern Mediterranean blood and bone marrow transplantation (EMBMT) group and the severe aplastic anemia working party of the European Society of blood and marrow transplantation (SAAWP of EBMT) related to the diagnosis and therapeutic options in countries with restricted resources.

Transplant in Aplastic Anemia Using Combined Granulocyte Colony-Stimulating Factor Primed Blood and Bone Marrow Stem Cells: A Retrospective Analysis

INTRODUCTION

Aplastic anemia (AA) is characterized by diminished hematopoietic precursors in the bone marrow, most often due to injury to the pluripotent stem cell. In Pakistan, AA is not uncommon, and allogeneic hematopoietic stem cell transplant remains the only curative option for these patients.

OBJECTIVE

The objective of this study was to determine the transplant outcome of combined granulocyte colony-stimulating factor (G-CSF) primed blood and bone marrow grafts in adult and pediatric patients with AA.

METHODS

We retrospectively collected the data of all transplant procedures performed from 2004 to 2019 at Aga Khan University in Karachi, Pakistan. Variables analyzed included age, sex, type of stem cells used, conditioning regimens, and overall survival for patients undergoing transplant in AA.

RESULTS

A total of 351 transplants were performed during the study period. Out of these, 239 were allogeneic transplants, whereas 112 were autologous procedures. We performed 70 transplants for AA during the study period, of which 52 were male patients and 18 were female patients. The median age ± standard deviation (SD) was 17.5 ± 9.4 years (range, 2-43 years). Cyclophosphamide/antithymocyte globulin (ATG) was used as a conditioning regimen in 65 patients, while ATG/cyclophosphamide/fludarabine was used in 5 patients. In 60 patients, a combination of G-CSF primed blood and bone marrow stem cells were used. The mean CD34 count was 5.2 × 10⁶/kg. Graft-vs-host disease (GVHD) prophylaxis was done with cyclosporine and methotrexate. All patients received standard infection prophylaxis. Engraftment was achieved in 86% of patients. The median day of myeloid engraftment was 15 (range, 10-22 days). Chronic GVHD was present in 3 patients while 4 had acute GVHD. The overall survival was 71.2% (median duration of 80 months). The main cause of mortality was gram-negative sepsis.

CONCLUSION

A combination of blood and bone marrow stem cells results in early engraftment with decreased frequency of GVHD in AA. The overall survival was comparable to international literature.

Narrowing the gap for hematopoietic stem cell transplantation in the East-Mediterranean/African region: comparison with global HSCT indications and trends

Hematopoietic Stem Cell Transplantation (HSCT) activity was evaluated in the African (AFR)/EMRO region and compared to the global activity for the years 2006-2013. Data were obtained from 1570 teams in the 6 WHO continental regions. Of these, 29 (1.85%) of all teams were active in 12 of the 68 AFR/EMRO countries. They reported 2.331 (3.3%) of the worldwide 71.036 HSCT, and a transplant rate of 32.8 (TR; HSCT/10 million inhabitants; worldwide 128.5). This reflects still the lowest regional TR despite an increase of 90% since 2006. HSCT activity in AFR/EMRO countries was characterized by a higher use of allogeneic compared to autologous HSCT, an almost exclusive use of family donors, including haploidentical family donors. These findings contrast with the prevalence of autologous over allogeneic HSCT, and a higher frequency of unrelated HSCT in other parts of the world. Of note, the increase by 200% in HSCT for hemoglobinopathies from 2006 to 2013 (72 per year) in the AFR/EMRO region. This reflects the specific role of HSCT for these disease categories with high prevalence and incidence in the AFR/EMRO region. This report provides information for the competent authorities to foster adequate infrastructure. It urges transplant organization to optimize their cooperation.

ATG vs thiotepa with busulfan and cyclophosphamide in matched-related bone marrow transplantation for thalassemia

Matched-related bone marrow transplantation (BMT) may cure >80% of low-risk children with severe thalassemia (ST). Very long-term follow-up studies have shown how the standard busulfan-cyclophosphamide (BuCy) regimen may be associated with normalization of health-related quality of life, no second malignancies in the absence of chronic graft-versus-host disease, and fertility preservation in many patients. However, because BuCy may be associated with high rejection rates, some centers incorporate thiotepa (Tt) in busulfan- or treosulfan-based regimens, a combination that may increase the risk of permanent infertility. This study retrospectively compares matched-related BMT outcomes in 2 groups of low-risk ST patients conditioned with either Tt or anti-thymocyte globulin (ATG) in addition to BuCy. A total of 81 consecutive first BMTs were performed in 5 collaborating startup BMT centers in the Indian subcontinent between January 2009 and January 2016; 30 patients were transplanted after conditioning with Tt-BuCy between January 2009 and July 2013, whereas between August 2013 and January 2016, 51 patients received ATG-BuCy. All patients were <15 years and had no hepatomegaly (liver ≤2 cm from costal margin). Actuarial overall survival in the Tt-BuCy and ATG-BuCy groups was 87% and 94% and thalassemia-free survival was 80% and 85% at a median follow-up of 37 and 17 months, respectively, with no significant differences by log-rank statistics. Substituting Tt with ATG in the standard BuCy context seems safe and effective and may decrease transplant-related mortality. Higher fertility rates are expected for patients who received ATG-BuCy.

First report of pediatric hematopoietic stem cell transplantation activities in the eastern mediterranean region from 1984 to 2011: on behalf of the pediatric cancer working committee of the eastern mediterranean blood and marrow transplantation group

To describe the hematopoietic stem cell transplantation (HSCT) activities for children in the Eastern Mediterranean (EM) region, data on transplants performed for children less than 18 years of age between 1984 and 2011 in eight EM countries (Egypt, Iran, Jordan, Lebanon, Oman, Pakistan, Saudi Arabia and Tunisia) were collected. A total of 5187 transplants were performed, of which 4513 (87%) were allogeneic and 674 (13%) were autologous. Overall, the indications for transplantation were malignant diseases in 1736 (38.5%) and non-malignant in 2777 (61.5%) patients. A myeloablative conditioning regimen was used in 88% of the allografts. Bone marrow (BM) was the most frequent source of stem cells (56.2%), although an increasing use of PBSC was observed in the last decade. The stem cell source of autologous HSCT has shifted over time from BM to PBSC, and 80.9% of autologous HSCTs were from PBSCs. The donors for allogeneic transplants were matched-related in 94.5% of the cases, and unrelated transplants, mainly cord blood (99%) in 239 (5.5%) cases. This is the first report to describe the pediatric HSCT activities in EM countries. Non-malignant disorders are the main indication for allogeneic transplantation. Frequency of alternate donor transplantation is low.

Comparing Outcomes with Bone Marrow or Peripheral Blood Stem Cells as Graft Source for Matched Sibling Transplants in Severe Aplastic Anemia across Different Economic Regions

Bone marrow (BM) is the preferred graft source for hematopoietic stem cell transplantation (HSCT) in severe aplastic anemia (SAA) compared with mobilized peripheral blood stem cells (PBSCs). We hypothesized that this recommendation may not apply to those regions where patients present later in their disease course, with heavier transfusion load and with higher graft failure rates. Patients with SAA who received HSCT from an HLA-matched sibling donor from 1995 to 2009 and reported to the Center for International Blood and Marrow Transplant Research or the Japan Society for Hematopoietic Cell Transplantation were analyzed. The study population was categorized by gross national income per capita and region/countries into 4 groups. Groups analyzed were high-income countries (HIC), which were further divided into United States-Canada (n = 486) and other HIC (n = 1264); upper middle income (UMIC) (n = 482); and combined lower-middle, low-income countries (LM-LIC) (n = 142). In multivariate analysis, overall survival (OS) was highest with BM as graft source in HIC compared with PBSCs in all countries or BM in UMIC or LM-LIC (P < .001). There was no significant difference in OS between BM and PBSCs in UMIC (P = .32) or LM-LIC (P = .23). In LM-LIC the 28-day neutrophil engraftment was higher with PBSCs compared with BM (97% versus 77%, P = .002). Chronic graft-versus-host disease was significantly higher with PBSCs in all groups. Whereas BM should definitely be the preferred graft source for HLA-matched sibling HSCT in SAA, PBSCs may be an acceptable alternative in countries with limited resources when treating patients at high risk of graft failure and infective complications.

Cord Blood Banking in the Arab World: Current Status and Future Developments

Umbilical cord blood transplants are now used to treat numerous types of immune- and blood-related disorders and genetic diseases. Cord blood (CB) banks play an important role in these transplants by processing and storing CB units. In addition to their therapeutic potential, these banks raise ethical and regulatory questions, especially in emerging markets in the Arab world. In this article, the authors review CB banking in five countries in the region, Jordan, Saudi Arabia, Egypt, Qatar, and the United Arab Emirates, selected for their different CB banking policies and initiatives. In assessing these case studies, the authors present regional trends and issues, including religious perspectives, policies, and demographic risk factors. This research suggests strong incentives for increasing the number of CB units that are collected from and available to Arab populations. In addition, the deficit in knowledge concerning public opinion and awareness in the region should be addressed to ensure educated decision-making.

Efficiency of allogeneic hematopoietic SCT from HLA fully-matched non-sibling relatives: a new prospect of exploiting extended family search

The best donors for hematopoietic SCT (HSCT) are fully-matched siblings. In patients without fully-matched siblings, HLA registries or cord blood banks are alternative strategies with some restrictions. Owing to the high rate of consanguineous marriage in our country, between 2006 and 2013, extended family searches were undertaken in Hematology-Oncology Research Center and Stem Cell Transplantation (HORCSCT), Tehran, Iran, in 523 HSCT candidates with parental consanguinity and no available HLA identical sibling. Fully-matched other-relative donors were found for 109 cases. We retrospectively studied the HSCT outcome in these patients. Median time to neutrophil engraftment was 13 days (range: 9-31days). In 83 patients, full chimerism and in 17 patients, mixed chimerism was achieved. Acute GvHD (aGvHD) grade II-IV appeared in 36 patients (33%). The frequency of aGvHD development in various familial subgroups was NS. Five patients expired before day+100. In the surviving 104 cases, chronic GvHD developed in 20 patients (19.2%). The distantly related subgroup had significantly a higher rate of cGvHD (P=0.04). The 2-year OS and disease-free survival (DFS) were 76.7±4.5% and 71.7±4.7%, respectively. No significant difference in OS (P=0.30) and DFS (P=0.80) was unraveled between various familial relationships. Our considerable rate of fully-matched non-sibling family members and the favorable outcome support the rationale for extended family search in regions where consanguineous marriage is widely practiced.

Allogeneic hematopoietic stem cell transplantation in adolescent and adult patients with high-risk T cell acute lymphoblastic leukemia

Allogeneic hematopoietic stem cell transplantation (allo-SCT) is often recommended for patients with T cell acute lymphoblastic leukemia (T-ALL) in second or later complete remission (≥CR2) and sometimes in high-risk (HR) patients in first complete remission (CR1). Between January 1995 and July 2009, 53 patients with HR T-ALL underwent allo-SCT at our institution. Median age was 18 years (range, 14-51). Thirty-two patients (60.3%) were in CR1, 18 (34%) were in ≥CR2, and 3 (5.7%) were in relapse. The cumulative incidence of nonrelapse mortality at 5 years was 22.5%. The cumulative incidence of grade II-IV acute graft-versus-host disease (GVHD) was 40.2%, and that of chronic GVHD was 43.7%. The majority of relapses (88.9%) occurred within 1 year after SCT. The cumulative incidence of relapse (CIR) at 5 years was 35.6%. CIR was 29.8% in patients in CR1, 35.3% in patients in ≥CR2 and all patients transplanted in relapse had disease recurrence post-allo-SCT (P = .000). Overall survival (OS) and disease-free survival (DFS) at 5 years were 43.5% and 41.8%, respectively. The 5-year OS was 53.5% (95% CI 34.5%-72.5%) and 5-year DFS was 52% (95% CI 33%-71%) in patients who underwent allo-SCT in CR1, compared with 31.9% (95% CI, 9%-54.8%) and 29.4% (95% CI 7.6%-51.2%) in those who underwent allo-SCT in ≥CR2. On multivariate analysis, disease status at SCT remained significantly associated with OS (P = .007), DFS (P = .002), and CIR (P = .000). The presence of extramedullary disease at diagnosis had no effect on the different outcomes. Grade II-IV acute GVHD was significantly associated with a lower OS (P = .006) and DFS (P = .01). Our data indicate that allo-SCT represents an effective treatment for HR T-ALL, particularly when performed in CR1.

Trends of hematopoietic stem cell transplantation in the Eastern Mediterranean region, 1984-2007

Hematopoietic stem cell transplantation (HSCT) activity was surveyed in the 9 countries in the World Health Organization Eastern Mediterranean region that reported transplantation activity. Between the years of 1984 and 2007, 7933 transplantations were performed. The number of HSCTs per year has continued to increase, with a plateau in allogeneic HSCT (allo-HSCT) between 2005 and 2007. Overall, a greater proportion of transplantations were allo-HSCT (n = 5761, 77%) compared with autologous HSCT (ASCT) (n = 2172, 23%). Of 5761 allo-HSCT, acute leukemia constituted the main indication (n = 2124, 37%). There was a significant proportion of allo-HSCT for bone marrow failures (n = 1001, 17%) and hemoglobinopathies (n = 885, 15%). The rate of unrelated donor transplantations remained low, with only 2 matched unrelated donor allo-HSCTs reported. One hundred umbilical cord blood transplantations were reported (0.017% of allo-HSCT). Peripheral blood stem cells were the main source of graft in allo-HSCT, and peripheral blood stem cells increasingly constitute the main source of hematopoietic stem cells overall. Reduced-intensity conditioning was utilized in 5.7% of allografts over the surveyed period. ASCT numbers continue to increase. There has been a shift in the indication for ASCT from acute leukemia to lymphoproliferative disorders (45%), followed by myeloma (26%). The survey reflects transplantation activity according to the unique health settings of this region. Notable differences in transplantation practices as reported to the European Group for Blood and Marrow Transplantation over recent years are highlighted.

High efficacy and low toxicity of short-course oral valganciclovir as pre-emptive therapy for hematopoietic stem cell transplant cytomegalovirus infection

BACKGROUND

Cytomegalovirus (CMV) infection is a major infectious complication post-allogeneic hematopoietic stem cell transplantation (HSCT). CMV seropositivity in Eastern Mediterranean and certain Asian countries is reported to be close to 100%; hence, the need for effective pre-emptive treatment strategy that has low toxicity. Valganciclovir (VGC) is a prodrug of ganciclovir with high bioavailability.

PATIENTS AND METHODS

HSCT patients with documented CMV infection (as defined by positive CMV antigenemia) were treated as outpatients with VGC at a starting dose of 900 mg twice daily for 1 week. Those who were antigenemia negative after one week received 900 mg once daily for another week and treatment was subsequently discontinued. Those who were positive after one week of therapy continued on the twice-daily treatment schedule for another week and changed to a daily schedule once they converted to antigenemia negativity.

RESULTS

From January 2004 to December 2007, 47 HSCT patients received preemptive treatment with VGC for 61 episodes of CMV infection. The antigenemia range was 1 to 700 infected cells/slide. Complete responses were observed in 92% and 97% after the 1st and 2nd week of treatment, respectively. Three percent of the episodes were considered refractory, requiring alternative therapy. No CMV disease was observed in this cohort.

CONCLUSION

Neutropenia was the main observed toxicity, requiring granulocyte-colony stimulating factor in 8 episodes. Outpatient treatment of CMV infection with "short-course oral VGC" given as a one-week twice-daily treatment and one week once daily maintenance is a highly effective therapy with minimal toxicity. These results require validation in a larger, randomized study.

Fludarabine-based conditioning chemotherapy for allogeneic hematopoietic stem cell transplantation in acquired severe aplastic anemia

Thirty-eight patients who met the diagnostic criteria for severe aplastic anemia underwent allogeneic hematopoietic stem cell transplantation (HSCT). The median patient age was 20 years (range, 14-36 years). Twenty-four patients were treatment-naïve, 11 had failed one or more previous courses of immunosuppressive therapy, and 3 had failed a previous HSCT. The conditioning regimen included fludarabine 30 mg/m(2)/day for 3 days (days -9, -8, and -7) and cyclophosphamide 50 mg/kg/day for 4 days (days -5, -4, -3, and -2). Graft-versus-host disease (GVHD) prophylaxis consisted of cyclosporine and short-course methotrexate. All patients underwent transplantation with unmanipulated bone marrow as the stem cell source. The median total nucleated cell (TNC) dose was 2.43 × 10(8)/kg (range, 0.60-6.7 × 10(8)/ kg). The conditioning regimen was well tolerated, with minimal treatment-related mortality. Engraftment was observed in all patients after transplantation; the median time to engraftment of neutrophils and platelets was 18 and 23 days, respectively. Twenty-five of the 27 patients with available chimeric studies at day 180 maintained donor chimerism. Acute GVHD grade ≥II was diagnosed in 4 patients (11%). Extensive chronic GVHD was observed in 8 patients (25%) who survived beyond day +100, at a median observation time of 43 months. Graft rejection with relapse of aplais was observed in one patient. The overall survival (OS) for the whole group was 79%. A trend toward improved OS was observed in the treatment-naïve patients (83% vs 71%), but this was statistically insignificant (P = .384). The fludarabine-based conditioning regimen used in this study with relatively young cohort of patients was well tolerated, with a low rate of rejection and treatment outcomes comparable to those seen in other, more intense and potentially more toxic conditioning regimens. Our results await validation in a larger study, optimally in a randomized controlled manner.

Outcomes of pediatric bone marrow transplantation for leukemia and myelodysplasia using matched sibling, mismatched related, or matched unrelated donors

Although some trials have allowed matched or single human leukocyte antigen (HLA)-mismatched related donors (mmRDs) along with HLA-matched sibling donors (MSDs) for pediatric bone marrow transplantation in early-stage hematologic malignancies, whether mmRD grafts lead to similar outcomes is not known. We compared patients < 18 years old reported to the Center for International Blood and Marrow Transplant Research with acute myeloid leukemia, acute lymphoblastic leukemia, chronic myeloid leukemia, and myelodysplastic syndrome undergoing allogeneic T-replete, myeloablative bone marrow transplantation between 1993 and 2006. In total, patients receiving bone marrow from 1208 MSDs, 266 8/8 allelic-matched unrelated donors (URDs), and 151 0-1 HLA-antigen mmRDs were studied. Multivariate analysis showed that recipients of MSD transplants had less transplantation-related mortality, acute graft-versus-host disease (GVHD), and chronic GVHD, along with better disease-free and overall survival than the URD and mmRD groups. No differences were observed in transplant-related mortality, acute and chronic GVHD, relapse, disease-free survival, or overall survival between the mmRD and URD groups. These data show that mmRD and 8/8 URD outcomes are similar, whereas MSD outcomes are superior to the other 2 sources. Whether allele level typing could identify mmRD recipients with better outcomes will not be known unless centers alter practice and type mmRD at the allele level.

Hematopoietic stem cell transplantation: a global perspective

CONTEXT

Hematopoietic stem cell transplantation (HSCT) requires significant infrastructure. Little is known about HSCT use and the factors associated with it on a global level.

OBJECTIVES

To determine current use of HSCT to assess differences in its application and to explore associations of macroeconomic factors with transplant rates on a global level.

DESIGN, SETTING, AND PATIENTS

Retrospective survey study of patients receiving allogeneic and autologous HSCTs for 2006 collected by 1327 centers in 71 participating countries of the Worldwide Network for Blood and Marrow Transplantation. The regional areas used herein are (1) the Americas (the corresponding World Health Organization regions are North and South America); (2) Asia (Southeast Asia and the Western Pacific Region, which includes Australia and New Zealand); (3) Europe (includes Turkey and Israel); and (4) the Eastern Mediterranean and Africa.

MAIN OUTCOME MEASURES

Transplant rates (number of HSCTs per 10 million inhabitants) by indication, donor type, and country; description of main differences in HSCT use; and macroeconomic factors of reporting countries associated with HSCT rates.

RESULTS

There were 50 417 first HSCTs; 21 516 allogeneic (43%) and 28 901 autologous (57%). The median HSCT rates varied between regions and countries from 48.5 (range, 2.5-505.4) in the Americas, 184 (range, 0.6-488.5) in Asia, 268.9 (range, 5.7-792.1) in Europe, and 47.7 (range, 2.8-95.3) in the Eastern Mediterranean and Africa. No HSCTs were performed in countries with less than 300,000 inhabitants, smaller than 960 km(2), or having less than US $680 gross national income per capita. Use of allogeneic or autologous HSCT, unrelated or family donors for allogeneic HSCT, and proportions of disease indications varied significantly between countries and regions. In linear regression analyses, government health care expenditures (r(2) = 77.33), HSCT team density (indicates the number of transplant teams per 1 million inhabitants; r(2) = 76.28), human development index (r(2) = 74.36), and gross national income per capita (r(2) = 74.04) showed the highest associations with HSCT rates.

CONCLUSION

Hematopoietic stem cell transplantation is used for a broad spectrum of indications worldwide, but most frequently in countries with higher gross national incomes, higher governmental health care expenditures, and higher team densities.

Trends of hematopoietic stem cell transplantation in the third millennium

PURPOSE OF REVIEW

Hematopoietic stem cell transplantation (HSCT) has evolved into an accepted therapy for many congenital or acquired disorders of the hematopoietic system. It has seen major changes in indications and use of transplant techniques. HSCT is a high cost procedure and requires investments; information on trends is essential for patient counselling and healthcare planning.

RECENT FINDINGS

HSCT rates have increased worldwide. Increase is constant and predictable; the reasons therefore are manifold. Introduction of reduced intensity conditioning regimens has opened access to patients at older age and with comorbidities. Higher numbers of unrelated volunteer donors and cord blood products give access to HSCT for patients without family donors. For some well defined indications, HSCT has become the most cost efficient therapy in countries with limited resources. Use of HSCT is under discussion for nonhematopoietic indications, as is the use of nonhematopoietic stem cells for organ repair.

SUMMARY

HSCT is likely to continue to increase for currently established indications. Indications and technologies will vary between countries with limited or nonrestricted resources. The most cost effective approach might not be the same everywhere. Novel indications will emerge but time will be needed to confirm their benefit. Close observation of global trends will become an essential tool for healthcare agencies in order to provide the necessary infrastructure in time.