Unrelated hematopoietic stem cell donors as research subjects

Ethical and Analytic Challenges With Genomic Sequencing of Relapsed Hematologic Malignancies Following Allogeneic Hematopoietic Stem-Cell Transplantation

The implementation of precision medicine and next-generation sequencing technologies in the field of oncology is a novel approach being more widely studied and used in cases of high-risk primary and recurrent malignancies. Leukemias are the second most common cause of cancer-related mortality in children and the sixth most in adults. Relapsed leukemia represents a major component of the population that may benefit from genomic sequencing. However, ethical and analytic challenges arise when considering sequencing of biologic samples obtained from patients with relapsed leukemia following allogeneic hematopoietic stem-cell transplantation. Blood from the recipient after transplantation would include donor-derived cells and thus, genomic sequencing of recipient blood will interrogate the donor germline in addition to the somatic genetic profile of the leukemia cells and the recipient germline. This is a situation for which the donor will not have typically provided consent and may be particularly problematic if actionable secondary or incidental findings related to the donor are uncovered. We present the challenges raised in this scenario and provide strategies to mitigate this risk.

Audits of collection and apheresis centers: guidelines by the World Marrow Donor Association Working Group Quality and Regulation

According to the Standards of the World Marrow Donor Association (WMDA), unrelated stem cell donor registries and donor centers are responsible for compliance of their collection and apheresis centers with these Standards. To ensure high stem cell product quality and high standards for safety and satisfaction of voluntary unrelated stem cell donors, we here present guidelines for audits of collection and apheresis centers that can be used by new and established donor registries, as well as by collection centers in preparation of audits. We define the general requirements and recommendations for collaboration with the collection and apheresis centers and define critical procedures for the collection of the stem cell product, such as information session, medical assessment, product collection, quality controls, product handover for transportation, and donor follow-up. The specific guidelines are accompanied by detailed checklists and forms that can be found in Supplementary Information and may be used during an initial or follow-up on-site or paper-based audit.

Research involving pediatric stem cell donors: A way forward

The most suitable donor for younger patients who undergo hematopoietic stem cell transplantation in the research setting is frequently a minor sibling. These cases raise the question of whether minors who serve as stem cell donors for research subjects should be regarded as research subjects themselves. Regarding pediatric donors as research subjects ensures that an Institutional Review Boards reviews their involvement and determines whether it is appropriate. Yet, Institutional Review Boards must follow the US regulations for pediatric research, which were designed for patients and healthy volunteers, not for healthy donors. As a result, regarding pediatric donors as research subjects also can pose unnecessary obstacles to appropriate and potentially life-saving research. This article considers a new way to address this dilemma. The federal research regulations allow for waiver of some or all of the included requirements when they are unnecessary for a study or a class of studies. We argue that this option offers a way to ensure that the involvement of pediatric donors receives sufficient review and approval without inadvertently undermining valuable and potentially life-saving research.

Lower risk for serious adverse events and no increased risk for cancer after PBSC vs BM donation

We compared serious early and late events experienced by 2726 bone marrow (BM) and 6768 peripheral blood stem cell (PBSC) donors who underwent collection of PBSC or BM between 2004 and 2009 as part of a prospective study through the National Marrow Donor Program. Standardized FDA definitions for serious adverse events (SAEs) were used, and all events were reviewed by an independent physician panel. BM donors had an increased risk for SAEs (2.38% for BM vs 0.56% for PBSC; odds ratio [OR], 4.13; P < .001), and women were twice as likely to experience an SAE (OR for men, 0.50; P = .005). Restricting the analysis to life-threatening, unexpected, or chronic/disabling events, BM donors maintained an increased risk for SAEs (0.99% for BM vs 0.31% for PBSC; OR, 3.20; P < .001). Notably, the incidence of cancer, autoimmune illness, and thrombosis after donation was similar in BM vs PBSC donors. In addition, cancer incidence in PBSC donors was less than that reported in the general population (Surveillance, Epidemiology, and End Results Program database). In conclusion, SAEs after donation are rare but more often occurred in BM donors and women. In addition, there was no evidence of increased risk for cancer, autoimmune illness, and stroke in donors receiving granulocyte colony-stimulating factor during this period of observation.

Validation of the EBMT Risk Score for South Brazilian Patients Submitted to Allogeneic Hematopoietic Stem Cell Transplantation

Background. Allogeneic hematopoietic stem cell transplantation (HSCT) is still associated with a high transplant-related mortality rate. In 2009, the EBMT risk score was validated as a simple tool to predict the outcome after allogeneic HSCT for acquired hematological disorders. Objectives. The aim of this study was to validate the applicability of the EBMT risk score for allogeneic HSCT on South Brazilian patients. Methods. A retrospective observational study was performed based on patients' records and data base at Hospital de Clínicas de Porto Alegre, including all allogeneic transplants for malignant and severe aplastic anemia from 1994 to 2010. Patients were categorized according to EBMT risk score and overall survival (OS). Nonrelapse mortality (NRM) and relapse rate (RR) were analyzed. Results. There were 278 evaluable patients. OS, NRM, and RR at five years median followup were 48.7%, 40.7%, and 30.7%, respectively. The OS was 81.8% for risk score 0 and 0% for score 6 (P < 0.001), and NRM was 13.6% and 80% for risk scores 0 and 6, respectively (P = 0.001). Conclusion. The EBMT risk score can be utilized as a tool for clinical decision making before allogeneic HSCT for malignant hematological diseases and severe aplastic anemia at a single center in Brazil.

Acute toxicities of unrelated bone marrow versus peripheral blood stem cell donation: results of a prospective trial from the National Marrow Donor Program

Although peripheral blood stem cells (PBSCs) have replaced bone marrow (BM) as the most common unrelated donor progenitor cell product collected, a direct comparison of concurrent PBSC versus BM donation experiences has not been performed. We report a prospective study of 2726 BM and 6768 PBSC donors who underwent collection from 2004 to 2009. Pain and toxicities were assessed at baseline, during G-CSF administration, on the day of collection, within 48 hours of donation, and weekly until full recovery. Peak levels of pain and toxicities did not differ between the 2 donation processes for most donors. Among obese donors, PBSC donors were at increased risk of grade 2 to 4 pain as well as grade 2 to 4 toxicities during the pericollection period. In contrast, BM donors were more likely to experience grade 2 to 4 toxicities at 1 week and pain at 1 week and 1 month after the procedure. BM donors experienced slower recovery, with 3% still not fully recovered at 24 weeks, whereas 100% of PBSC donors had recovered. Other factors associated with toxicity included obesity, increasing age, and female sex. In summary, this study provides extensive detail regarding individualized risk patterns of PBSC versus BM donation toxicity, suggesting donor profiles that can be targeted with interventions to minimize toxicity.