Hematopoietic stem cell transplantation in Saudi Arabia between 1984 and 2016: Experience from four leading tertiary care hematopoietic stem cell transplantation centers.

Saudi Arabia is the largest of the Arabian Gulf countries with a total population of 33.41 million as of 2017. This report summarizes the experience from four leading tertiary care hematopoietic stem cell transplantation (HSCT) centers in Saudi Arabia representing more than 90% of all HSCTs performed in the country. Between 1984 and 2016, a total of 6,184 HSCTs were performed. Of these, 3,586 HSCTs were performed in adults and 2,598 HSCTs were performed in pediatric patients. Malignancy was the main indication for transplantation (47%). While most transplants were performed from an identical sibling donor, HSCTs from cord blood, unrelated and, more recently, haploidentical donors have also been performed. Relative shortage of HSCT bed capacity is perceived to be a limiting factor in Saudi Arabia. Lately, more HSCT centers are emerging with rapid growth, which may significantly improve the access to HSCT in the country in the near future.

Improved outcomes with allogeneic hematopoietic cell transplantation.

Over the last 2 decades, there have been a number of changes in clinical practice that individually could affect the outcome of allogeneic hematopoietic cell transplantation (HCT), but until recently the collective impact of these changes was unknown. Accordingly, several groups asked the question of whether the outcome of allogeneic HCT has improved, and if so, why. Four large studies including a total of more than 10,000 patients have been performed and have reached very similar conclusions. Compared to transplants performed in the 1990s, the hazard ratio for nonrelapse mortality for transplants performed in the 2000s was roughly 0.5. This remarkable improvement was seen when the analyses were restricted to myeloablative transplants, to recipients of marrow rather than peripheral blood, or to transplants from matched siblings, and persisted after analyses were adjusted for patient risk. Likely explanations for this improvement include the avoidance of the most toxic preparative regimens, use of agents that spare hepatic and renal function, and improved methods for control of infections.

The national marrow donor program 20 years of unrelated donor hematopoietic cell transplantation.

In the 20 years since the National Marrow Donor Program (NMDP) facilitated the first unrelated donor transplant, the organization has grown to include almost 7 million donors, and has facilitated over 30,000 transplants on 6 continents. This remarkable accomplishment has been facilitated by the efforts of over 600 employees, and an extensive international network including 171 transplant centers, 73 donor centers, 24 cord blood banks, 97 bone marrow collection centers, 91 apheresis centers, 26 HLA typing laboratories, and 26 Cooperative Registries. In this article, we review the history of the NMDP, and cite the major trends in patient demographics, graft sources, and conditioning regimens over the last 20 years.

EBMT activity survey 2004 and changes in disease indication over the past 15 years.

This fifteenth annual European Group for Blood and Marrow Transplantation activity report lists the transplant activity in Europe in 2004 and documents the changes in indication over the past 15 years. In 2004, there were 22 216 first hematopoetic stem cells (HSCT), 7407 allogeneic (33%), 14 809 autologous (67%) and 4378 additional re- or multiple transplants reported from 592 centres in 38 European and five affiliated countries. Main indications were leukemias (7045 (32%; 78% allogeneic)); lymphomas (12 310 (55%; 94% autologous)); solid tumors (1759 (8%; 93% autologous)) and nonmalignant disorders (1015 (5%; 92% allogeneic)). In comparison, 145 teams from 20 countries performed 4234 HSCT (2137 allogeneic, 50%; 2097 autologous, 50%) in 1990. The overall increase was accompanied by major changes. Stem cell source changed from bone marrow to peripheral blood. More than one-third of allogeneic HSCT are now from unrelated donors. Reduced intensity conditioning is employed for one-third of allogeneic HSCT. Leukemias for allogeneic and lymphoproliferative disorders for autologous HSCT continue to increase. The decline in HSCT for chronic myeloid leukemia appears to level off for the first time since 1999. These data are informative for patient counselling and decision making for health care professionals.

Radioimmunotherapy for non-Hodgkin's lymphomas: a historical perspective.

One of the most promising therapeutic approaches currently under investigation for low-grade non-Hodgkin's lymphoma is the administration of monoclonal antibodies that recognize tumor-associated antigens. These antibodies can be used either in unmodified form or conjugated to cytotoxic drugs, toxins, or radionuclides. To date, the most promising of the immunoconjugates are radiolabeled antibodies. Radioimmunotherapy is an attractive approach because radiolabeled antibodies are effective even in the face of defective host immune effector function, antigen-negative variants, and poor penetration of the antibody into tumors. Iodine-131-and Yttrium-90-conjugated antibodies have shown superior response rates compared with unconjugated antibodies and have produced complete responses in 15% to 40% of treated patients. A variety of treatment approaches are currently being investigated, including administering radiolabeled antibodies in combination with chemotherapy and administering myeloablative doses with stem-cell rescue. This latter strategy has yielded complete remissions in the majority of treated patients, some durable for more than 5 years.