Abstract
Purpose
To characterize donor search and selection practices, the National Marrow Donor Program (NMDP) Histocompatibility Advisory Group developed a survey of allogeneic hematopoietic cell transplant (HCT) physicians and search coordinators. Objectives were to describe search practices, understand practices surrounding urgent time to HCT, and characterize strategies used when identifying a matched unrelated donor (MUD) is unlikely.
Methods
Participants included United States physician members of the American Society for Transplantation and Cellular Therapy (ASTCT) and donor search coordinators within the NMDP network. The web-based survey was conducted February to May 2018.
Results
A total of 317/858 physicians (37%) and 225/327 coordinators (69%) responded, of which 263 and 194 respectively were eligible and were included in the analysis. Most centers, 142 (95%) were represented; 108 (72%) had at least one physician and 128 (85%) had at least one coordinator respondent. Most (68% physicians, 61% coordinators) indicated donor selection decisions were made by individual physicians. Urgent time to HCT was most commonly (90 and 87%, of physicians and coordinators, respectively) defined as HCT within 4–6 weeks of search nitiation. Higher HCT urgency was associated with a higher disease risk index. For urgent cases with low probability of an 8/8 MUD, 75 and 80% of physicians and coordinators endorsed short (1–2 weeks) unrelated donor search before proceeding to an alternative donor source. NMDP-provided solutions to expedite donor identification were strongly endorsed.
Conclusions
This survey clarified current donor selection practices in the United States and defined urgent time to HCT. These data provide insight to NMDP on potential solutions to support the path to transplant, such as highlighting futile searches and providing alternative donor options at the time of search initiation.
Keywords: Allogeneic hematopoietic cell transplantation, allogeneic donors, National Marrow Donor Program, donor selection, urgent time to transplant
INTRODUCTION
Identification of a suitable donor is a required initial component of facilitating allogeneic hematopoietic cell transplantation (HCT) for patients with hematologic disorders. No uniform standards exist across HCT centers in this regard, and it is expected that the practices of individual HCT physicians differ according to multiple factors, including institutional standards, patient characteristics, and individual preferences. In addition, the interaction between HCT physicians and donor search coordinators to achieve a preferred donor source for HCT has not been examined.
Variations in these practices may be especially important for patients with increased disease risk, as relapse or disease progression represents the most common reasons why otherwise eligible patients do not reach HCT.[1, 2] However, the concept of urgent time to HCT has not been investigated previously, and insight is needed into provider-level definitions of urgency and practices employed in this context, with attention to barriers encountered, and selection of alternative donors when well-matched unrelated donors (MUD) are not available. Multiple existing and potential future strategies to improve the efficiency of donor identification are possible, [3–6] yet physician and donor search coordinator acceptance of these solutions has not been explored.
The Histocompatibility Advisory Group (HAG) to the National Marrow Donor Program (NMDP)/Be The Match is a key opinion leader group composed of experts in HLA science, unrelated donor registries, and HCT clinicians. The HAG conducted a national survey of practicing HCT physicians and unrelated donor search coordinators to characterize current donor search practices, examine urgent time to HCT and its association with disease risk, practices in the setting of low probability of MUD, and acceptance of NMDP-provided solutions to optimize the efficient identification of a suitable donor.
METHODS
Participant eligibility criteria
Selection criteria included United States HCT physician members of the American Society for Transplantation and Cellular Therapy (ASTCT, formerly named American Society for Blood and Marrow Transplantation) and unrelated donor search coordinators within the national NMDP network directly involved in donor/cord blood unit (CBU) selection. Member names, credentials, HCT center, titles and email addresses were obtained from ASTCT and NMDP, and these membership lists were reserved for a single use only for the purpose of this survey.
Survey development and content areas
The survey was developed in seven major content areas and refined by the HAG study group for face validity, clarity, and total expected time for completion. The survey was piloted with input from HCT physicians and search coordinators. Two parallel versions of the survey were developed to separately target practicing HCT physicians and unrelated donor search coordinators, and each was projected to require up to 25 minutes for completion. Content was largely identical in both surveys to permit study of concordance in responses across physicians and coordinators, except that only physicians were asked to characterize urgency according to disease and disease risk categories. The two surveys are provided as Supplementary materials (Item S1, Item S2).
The seven major content areas were:
Respondent demographics, including identification of HCT center, patients treated (adult vs. pediatric vs. both), years of experience in HCT, and board certification. Search coordinators provided years of experience and certification.
Existing donor search practices at HCT center, including usual unrelated donor or CBU search practices at the center, rank ordering of preferred donor types at search initiation, and physician/search coordinator communication in the search process. Finally, respondents were asked to affirm which NMDP-supported resources their center uses when evaluating unrelated donor and CBU search results.
Definitions of HCT urgency and associated practices in this setting, including urgency of timeline as defined from search initiation to HCT infusion, agreement in a shared definition of urgency at the HCT center, proportion of HCT patients in past year that required urgent time to HCT, presence of a uniform system to determine urgency at the HCT center, resources used to expedite urgent HCT, alternative graft sources considered when 8/8 MUD is not available, and association of urgency in time to HCT with varied types of disease risk groups (an abbreviated list of common disease/remission groups based on the published Disease Risk Index, or DRI).[7]
Barriers to reaching HCT on desired timeline,[8, 9] including those experienced when concurrently pursuing stem cell sources for HCT, barriers experienced in urgent cases, percentage of urgent cases where inability to promptly identify stem cell source affect desired timeline to HCT, and percentage of urgent cases not able to reach HCT on the desired timeline due to barriers.
Practices in the setting of low probability of 8/8 MUDs (defined in the survey only as low probability, not using specific search prognosis data or actual search results), including acceptable ongoing unrelated donor search time for urgent cases in setting of initial search results demonstrating low likelihood of an 8/8 MUD before pursuing other stem cell sources, acceptable ongoing search time for non-urgent cases in setting of initial search results demonstrating low likelihood of 8/8 MUD before pursuing other stem cell sources, and alternative cell sources pursued in setting of low likelihood of 8/8 MUD.
HCT physician and search coordinator communication, including confidence in estimating time to HCT at start of search initiation, search coordinator confidence in providing early feedback when preferred donor source is unlikely to be achieved, and prompt action on search coordinator feedback regarding low probability of achieving the preferred product.
Acceptance of current and potential future NMDP-provided solutions to facilitate timely identification of a suitable donor for HCT (a “STAT” service to identify HLA confirmatory typed and available unrelated donors within 14 days of formal activation or notification of alternate strategies,[6] a ‘search prognosis’ indicator within the coordinator search application[5], and HapLogic matching predictions supplied for entire Bone Marrow Donors Worldwide donor list).[4]
Survey conduct
Potential participants were sent a personalized email invitation to complete the survey through Snap Surveys (www.snapsurveys.com). The survey was released in February 2018 with 5 reminder email blasts issued before survey closure in May 2018. Initial screening questions determined whether the physician or search coordinator was directly involved in unrelated donor/CBU search and selection decision making for allogeneic HCT patients in the US. The incentive was the possibility to win a $100 gift card by random drawing, with a total of 100 possible winners. All participants agreed to participate in the research survey with the understanding that participation was voluntary and that answers would not be linked to any personally identifying information. The NMDP Institutional Review Board approved the study.
Analytic methods
The primary aims of this study were descriptive in nature. We used descriptive statistics, including frequencies and percentages, to examine physician and coordinator responses to survey items. Chi-square and Fisher’s exact test were used to identify differences between physician and coordinators’ practice and perceptions in “urgent” allogenic HCT.
All statistical analyses were performed using SAS Enterprise Guide (V6.1).
RESULTS
Participant characteristics
Survey respondent characteristics are shown in Table 1. A total of 317/858 (37%) physicians and 225/327 (69%) coordinators responded, of which 263 physicians and 194 coordinators met the eligibility criteria and were included in the analysis. The differential from number of respondents to eligible subjects was due to removal of ineligible subjects, most commonly due to partial completion of the survey, response indicating that the respondent had no direct role in donor search and selection practices, or failure to provide consent for the survey. Most (142 of 150 [95%]) centers were represented, 72% and 85% of centers had at least one physician and one coordinator complete the survey, respectively. A greater proportion of physicians represented adult only centers, compared to coordinators. Oncology and hematology were the most common physician board certification while search coordinators were most commonly registered nurses (RN) and/or certified hematopoietic transplant coordinators (CHTC). A greater proportion of physicians reported greater than 10 years of experience than coordinators (64 and 41%, respectively p< 0.0001).
Table 1.
Survey Respondent Characteristics
| Characteristics | Physicians N=263 (%) |
Coordinators N=194 (%) |
Total N=457 (%) |
P-value1 |
|---|---|---|---|---|
| Patient population | ||||
| Adults only | 166 (63.1) | 105 (54.1) | 271 (59.3) | 0.0035 |
| Pediatrics only | 68 (25.9) | 45 (23.1) | 113 (24.7) | |
| Adults and Pediatrics | 29 (11.0) | 44 (22.7) | 73 (16.0) | |
| Years of experience in unrelated HCT | ||||
| <1 | 3 (1.1) | 17 (8.8) | 20 (4.4) | <0.0001 |
| 1–5 | 46 (17.5) | 60 (30.9) | 106 (23.2) | |
| 6–10 | 46 (17.5) | 37 (19.1) | 83 (18.2) | |
| >10 | 168 (63.9) | 80 (41.2) | 240 (52.5) | |
| Physician board certification* | ||||
| Hematology | 132 (50.2) | |||
| Oncology | 130 (49.4) | |||
| Internal Medicine | 112 (42.6) | |||
| Pediatric | 90 (34.2) | |||
| Hematology/Oncology | ||||
| Pediatrics | 47 (17.9) | |||
| Other | 11 (4.2) | |||
| Search coordinator years at center | ||||
| <1 | 14 (7.2) | |||
| 1–5 | 44 (22.7) | |||
| 6–10 | 29 (14.0) | |||
| >10 | 107 (55.2) | |||
| Search coordinator credentials* | ||||
| Registered Nurse (RN) | 144 (74.2) | |||
| Certified Hematopoietic Transplant Coordinator (CHTC) | 58 (29.9) | |||
| Other¥ | 84 (43.3) |
Determined by χ2 test.
Respondents could select all that applied.
Other included: Oncology Certified Nurse (OCN) (n=25); Bone Marrow Transplant Certified Nurse (BMTCN) (n=18); BSN (15); Master’s degree (n=9); Bachelor’s degree (n=8); Medical Technology (6); None (n=3).
HCT, hematopoietic cell transplantation
Usual donor search practices
When asked to select all that apply, the majority of both physicians (73.8%) and coordinators (80.4%) reported that donor search practices were guided by a center selection algorithm, but final decisions were made by individual treating physicians. A group roundtable discussion (35.4 and 35.6%) or decision driven by research protocols (19.0 and 22.7%) were less commonly endorsed by physicians and coordinators, respectively. Other approaches including strict adherence to a center selection protocol (10.6 and 10.3%), individual physician decision without a shared algorithm (8.0 and 8.8%), or a single center representative decision maker (4.6 and 9.8%) were not commonly reported by both physician and coordinators, respectively.
The majority of physicians and coordinators (98% and 97%, p=0.37) indicated that matched sibling donors were prioritized when available (ranked as first among the available donor options), and most (76 and 66%, p=0.02) of physicians and coordinators, respectively, ranked an 8/8 MUD as the second preferred donor option. Among alternative donor types, 41 and 37% (p=0.018) of physicians and coordinators, ranked haploidentical donors as third in priority, while 24 and 18% (p=0.0007) of physicians and coordinators, ranked UCB third, 15 and 10% (p= NS) of physicians and coordinators ranked 7/8 unrelated donors third. Less than 8% of physicians and coordinators ranked the above alternative donor types as the first priority option among potential donor types.
Most physicians and coordinators either agreed or strongly agreed that there was good communication between the clinical team and unrelated donor search coordinator. However physicians were more likely than coordinators to strongly agree (80 and 67%, respectively p=0.17) that there was good communication on urgency and timeline for a given patient’s HCT, and likelihood of availability of the preferred stem cell source (66 and 53% respectively, p=0.017).
When asked to report any/all NMDP-supported resources used when evaluating unrelated donor and CBU searches, 81% of coordinators reported using NMDP search strategy advice/HLA consultation, 68% reported using HapLogic donor and CBU match prediction output (68%,), and 84% reported using donor and CBU list view in Traxis®. Less than 1% of coordinators indicated that they were unaware of the listed NMDP-supported resources. Similarly less than 1% reported that they had not found them to not be helpful in the past.
HCT urgency
The majority (90 and 87%, p= 0.19) of physicians and coordinators indicated that urgent cases had a timeline of 6 weeks or less from unrelated search initiation (assuming no matched sibling donor option) to HCT infusion Figure 1. Interestingly, 62 and 84% (p<0.0001) of physicians and coordinators indicated that the definition of urgency was shared amongst transplant physicians at their center, yet most physicians and coordinators (67 and 62%, p=0.23) indicated that each physician has their own system to determine which patients are urgent, rather than an agreed upon system used by all physicians.
Figure 1: Physician and search coordinator definitions of urgent time to transplant defined as time from unrelated donor search initiation to cell infusion.
* Percentages reported for each category. No significant differences between physicians and coordinators.
More physicians than coordinators (81 and 58%, respectively, (p<0.0001)) reported that ≤25% of HCT candidates at their center had to proceed to HCT within 6 weeks from time of unrelated donor search initiation.
Urgent time to HCT (defined here as HCT within 6 weeks from unrelated donor search initiation to HCT infusion) was associated with escalating disease/disease risk status (Figure 2). These disease/remission status/prognostic subgroup variants were selected to represent variation within each disease type across the spectrum of the DRI.
Figure 2: Variation in reported urgent time to transplant according to disease diagnosis and disease risk index categories.
* AML, acute myeloid leukemia; ALL, acute lymphocytic leukemia; MDS, myelodysplastic syndrome; MPN, myeloproliferative neoplasms; CML, chronic myeloid leukemia. Figure 2 displays the percentage of physician respondents who classified the disease and risk characteristics scenario as urgent (defined here as no more than 6 weeks from unrelated donor search submission to infusion day).
Many available strategies were commonly used to expedite time to HCT among urgent cases, with multiple donors requested concurrently for workup (70 and 53%), prioritized analysis of donor by TC search coordinator (56 and 67%), requesting confirmatory typing and workup concurrently (51 and 63%) and selecting donors with recent contact status for improved donor availability (31 and 61%), being the most prevalent among physicians and coordinators, respectively. Physicians and coordinators reported using one or more alternative donors for urgent cases when 8/8 matched unrelated donors were not available (90 and 94% haploidentical, 63 and 57% CBU, 46 and 43% mismatched unrelated, respectively).
Barriers to reach HCT on desired timeline among urgent cases
The most commonly reported barriers to reaching HCT on the desired timeline reported by physician and coordinators, included receiving HLA typing results for patient and donor (48 and 57%), inability of the unrelated registry to provide timely donor collection date (61 and 62%), and insurance issues (58% for both). Less commonly reported barriers included scheduling additional tests for the patient (29 and 41%), hospital bed space (16 and 15%), scheduling HCT radiotherapy or other therapy (20 and 28%), or cell therapy lab schedule (22 and 21%), respectively.
Physicians and coordinators reported experiencing one or more of the following barriers when concurrently pursuing all HCT cell sources for urgent cases: insurance approval (64 and 60%), lack of time for search coordinator to analyze these options concurrently (29 and 34%), or other (15 and 16%). Less than 4 and 14% of physicians and coordinators, respectively, reported that they do not pursue different cell sources concurrently for urgent cases.
The ability to identify a stem cell source for urgent cases was not commonly selected as a significant barrier: Most (80%) physicians and coordinators reported that identifying a stem cell source limited the ability to proceed to transplant in the desired timeline in 25% or less of their usual urgent cases, with no significant differences between the two groups. Similarly, 83% of both physicians and coordinators reported that 25% or less of urgent cases could not reach HCT on the desired timeline due to barriers.
Search practices after low probability of 8/8 MUD
In the setting of a perceived urgent case, respondents allowed little time for ongoing MUD search activity before proceeding to alternative donors when initial results indicated low probability of 8/8 MUD (additional search time of 1 week, 37%; 2 weeks, 40%; 1 month:19%; or 2 months or greater, 4%), with no significant differences between physicians and coordinators. Preferred strategies explored in this setting included haploidentical donors, CBU, and 7/8 unrelated donors, with non-HCT therapy, research protocol driven source selection, or other, less often pursued (Figure 3).
Figure 3: Strategies pursued in the setting of low probability of an 8/8 HLA matched unrelated donor.
*HLA, human leukocyte antigen; MUD, matched unrelated donor; CBU, cord blood unit; Haplo, haploidentical related donor; mMRD, mismatched related donor; HCT, hematopoietic cell transplantation. Percentages reported for each alternative cell source (Select all that apply).
In contrast, a greater proportion allowed additional unrelated donor search time in the setting of non-urgent cases (additional search time of 1 week, 4%; 2 weeks, 10%; 1 month, 38%; or 2 months or greater 48%), with no significant differences between physicians and coordinators.
HCT physician and coordinator communication
More physicians than coordinators reported agreement (% agree or strongly agree) that ‘My unrelated donor search coordinator is (MD survey)/I am (coordinator survey) confident in estimating time to HCT from time of search initiation’ (71 and 65%, respectively, p<0.0055). Similarly a greater proportion of physicians than coordinators (94% and 88%, p=0.018) reported that ‘the clinical team acts promptly on feedback regarding low probability of achieving the preferred product.’ However there were no significant differences between physician and coordinator responses when asked if ‘my unrelated donor search coordinator is (MD survey)/ I am (coordinator survey) confident in providing feedback early in a search when the preferred donor source is unlikely to be achieved’ (89% for both).
Acceptance of NMDP-provided solutions
Most physicians and coordinators highly supported (% agree or strongly agree) NMDP current or future potential solutions to facilitate rapid identification of suitable donors for HCT, including a “STAT” service to identify HLA confirmatory typed and available unrelated donors within 14 days of formal activation or notification of alternate strategies (86%), a ‘search prognosis’ indicator within the coordinator search application (77%), and HapLogic matching predictions supplied for entire Bone Marrow Donors Worldwide donor list (78%), with no significant differences between physicians and coordinators.
Discussion
This national survey of HCT physicians and donor search coordinators provides comprehensive insight into usual donor search and selection practices, urgent time to HCT, decision making when matched unrelated donor options are limited, and provider-level endorsement of strategies to enhance efficient identification of donors.
The data indicate that, under usual practices, HCT physicians and search coordinators work together in a coordinated manner to achieve the desired donor in the desired time frame. Communication on urgency, preferred donor type, or donor alternatives does not appear to be a major barrier within the clinical team. With the assistance of existing NMDP search resources and guidance from center selection algorithms, HCT physicians largely individually drive donor selection decisions, using an expected donor priority ranking (preferential ranking of matched siblings, then MUD, followed by heterogeneous use of alternative donors).
As urgent time to HCT appears to be largely defined as within 4–6 weeks from unrelated donor search initiation to HCT infusion, strategies to efficiently identify suitable donors and reach HCT are needed. This rapid timeline appears to be indicated for the minority of usual HCT candidates, and is associated with increased disease risk. Under current practices, multiple means are already utilized to reach HCT quickly among urgent cases. Most indicated allowing no more than 2 weeks of additional unrelated donor search time after initial search indicating low probability of an 8/8 MUD, and use of alternative donor types were highly endorsed in this setting. As most endorsed pursuing multiple donor sources concurrently, inability to identify a suitable donor of any type is an uncommon barrier for the desired time to HCT for urgent cases. Additional innovative NMDP resources to enhance early notice of search prognosis and ultra-rapid provision of available donors were highly endorsed. As the use of haploidentical transplantation increases and may benefit from related donors who may be highly engaged and located within proximity to the treating transplant program for readily available donation, more research is needed to understand whether the current speed possible for MUD donors versus haploidentical should cause differential clinical decisions.
The main barriers identified by this survey included the time delay in receiving HLA typing results for patient and donor, inability of the unrelated registry to provide timely donor collection date, and insurance issues. The NMDP continues to seek to understand and implement processes that can better enable the search and selection of donors to achieve rapid patient time to transplant. New initiatives are aimed at obtaining the desired time to transplant at the initiation of the patient search, to better inform requested donors of the need and provide information back to the transplant center if other options should be pursued. Despite over two-thirds of physician and coordinator survey respondents being confident in estimating time to HCT at time of search initiation, NMDP currently receives data on less than one-third of patient cases [internal NMDP data]. This is recommended as an area of opportunity for center practice. In addition, FastTrackSM Search is a new service that is intended for patients with urgent time to transplant and includes accelerated donor screening using the transplant center’s prioritized list of potential donors, preferred product for the transplant, and target collection timeframe. HLA confirmatory testing is performed at a centralized laboratory with results in 3 business days. Comprehensive updates from the NMDP case manager provide progress so timely decisions can be made by the HCT clinical team. To address insurance coverage based barriers, NMDP has focused on implementing strategies and working with payers. This includes working with stakeholders to create an essential health benefit set for transplant to be used by payers, creating a care coordination toolkit for payers to have “one-stop” for information on care along the patient continuum, and creating resources and publishing papers on a set of standard indications for policymakers to use to address coverage for HCT. Additionally, NMDP has a grant program that offers financial assistance for patients who are not insured or do not have search assistance benefits in their insurance plan, to cover the donor search process. NMDP intends to continue identifying specific insurance challenges inhibiting timely transplantation.
In addition, MatchSource® was released in July 2019 as the HCT center software to manage the search and selection process, which applies HapLogic algorithm assessment to all worldwide donors and CBU sources. Future provision of a search prognosis indicator into the HCT center software is also planned to better assist HCT centers in the characterization of difficult searches to encourage early decisioning and escalation of selection expertise.
We acknowledge the following limitations of this work: First, while most surveyed HCT centers were represented, potential threats to this work include relatively low physician response rate, predominantly limited number of respondents per center, and representation of US centers only. Based on limited respondents per center, we could not adequately address variation in responses within centers. Second, we acknowledge that the survey content and presentation could not fully recapitulate real-world circumstances that inform providers’ decision making regarding donor selection, especially as required in urgent cases: We did not address the impact of race and ethnicity on search prognosis and donor selection,[10] but rather focused generally on practices in the setting of low likelihood of well-matched unrelated donors. As well, the survey did not invoke potential differences in HCT outcomes according to alternative donor types. Also, survey content examining urgency as a function of disease risk appealed to an abbreviated set of DRI-based categories, and did not examine either the full range of disease and disease remission subgroups, or include other factors (e.g. molecular markers of disease risk, nuances of treatment history and response, patient-level specific considerations) that likely play a role in usual decision making. Finally, the section on urgency and disease risk did not include non-malignant disorders, thus in part limiting relevance to pediatric HCT physicians.
This national survey clarified current donor selection decision making practices in the United States and defined urgent time to HCT. These data provide insight to NMDP on potential solutions to support the path to transplant, such as highlighting futile searches and providing alternative donor options at the time of search initiation. NMDP recommends that transplant centers maintain a uniform selection process across providers, with close communication with their search coordinators and utilization of NMDP resources, to enable donor selection and transplantation in the preferred timeframe for optimal recipient outcomes.
Supplementary Material
Highlights.
Urgent time to transplant is most commonly defined by physicians and coordinators as transplant within 4–6 weeks from search initiation
Transplant urgency, classified by physicians, varies according to disease risk
Providers allow brief unrelated donor search time for urgent transplants
Providers highly endorse alternative donor types when a well-matched unrelated donor is unlikely
Acknowledgements
We thank all the transplant physicians and coordinators for participating in the survey and sharing their valuable insights. We thank ASBMT for support in provision of membership lists for survey invitations.
Footnotes
Publisher's Disclaimer: This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.
References
- 1.Heemskerk MB, van Walraven SM, Cornelissen JJ, Barge RM, Bredius RG, Egeler RM, Tj Lie JL, Revesz T, Sintnicolaas K, Wulffraat NM, Donker AE, Hoogerbrugge PM, van Rood JJ, Claas FH, Oudshoorn M. How to improve the search for an unrelated haematopoietic stem cell donor. Faster is better than more! Bone Marrow Transplant 2005;35:645–652. [DOI] [PubMed] [Google Scholar]
- 2.Pidala J, Kim J, Schell M, Lee SJ, Hillgruber R, Nye V, Ayala E, Alsina M, Betts B, Bookout R, Fernandez HF, Field T, Locke FL, Nishihori T, Ochoa JL, Perez L, Perkins J, Shapiro J, Tate C, Tomblyn M, Anasetti C. Race/ethnicity affects the probability of finding an HLA-A, -B, -C and -DRB1 allele-matched unrelated donor and likelihood of subsequent transplant utilization. Bone Marrow Transplant 2013;48:346–350. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 3.Davis E, Devlin S, Cooper C, Nhaissi M, Paulson J, Wells D, Scaradavou A, Giralt S, Papadopoulos E, Kernan NA, Byam C, Barker JN. Validation of an Algorithm to Predict the Likelihood of an 8/8 HLA-Matched Unrelated Donor at Search Initiation. Biol Blood Marrow Transplant 2018;24:1057–1062. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 4.Dehn J, Setterholm M, Buck K, Kempenich J, Beduhn B, Gragert L, Madbouly A, Fingerson S, Maiers M. HapLogic: A Predictive Human Leukocyte Antigen-Matching Algorithm to Enhance Rapid Identification of the Optimal Unrelated Hematopoietic Stem Cell Sources for Transplantation. Biol Blood Marrow Transplant 2016;22:2038–2046. [DOI] [PubMed] [Google Scholar]
- 5.Wadsworth K, Albrecht M, Fonstad R, Spellman S, Maiers M, Dehn J. Unrelated donor search prognostic score to support early HLA consultation and clinical decisions. Bone Marrow Transplant 2016;51:1476–1481. [DOI] [PubMed] [Google Scholar]
- 6.Stritesky G, et al. NMDP expedited search process: Selection, typing and transplant (STaT). Biology of blood and marrow transplantation 2019;25:s218. [Google Scholar]
- 7.Armand P, Kim HT, Logan BR, Wang Z, Alyea EP, Kalaycio ME, Maziarz RT, Antin JH, Soiffer RJ, Weisdorf DJ, Rizzo JD, Horowitz MM, Saber W. Validation and refinement of the Disease Risk Index for allogeneic stem cell transplantation. Blood 2014;123:3664–3671. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 8.Murphy EA, Ferguson SS, Omondi NA, Getzendaner LC, Gajewski JL, Goldstein GA, Wingard JR, Rizzo JD, Majhail NS. The National Marrow Donor Program’s symposium on patient advocacy in cellular transplantation therapy: addressing barriers to hematopoietic cell transplantation. Biol Blood Marrow Transplant 2010;16:147–156. [DOI] [PubMed] [Google Scholar]
- 9.Majhail NS, Omondi NA, Denzen E, Murphy EA, Rizzo JD. Access to hematopoietic cell transplantation in the United States. Biol Blood Marrow Transplant 2010;16:1070–1075. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 10.Gragert L, Eapen M, Williams E, Freeman J, Spellman S, Baitty R, Hartzman R, Rizzo JD, Horowitz M, Confer D, Maiers M. HLA match likelihoods for hematopoietic stem-cell grafts in the U.S. registry. N Engl J Med 2014;371:339–348. [DOI] [PMC free article] [PubMed] [Google Scholar]
Associated Data
This section collects any data citations, data availability statements, or supplementary materials included in this article.