Patients of non-white northern European descent have better access to transplant than ever before due to access to cord blood and haploidentical transplants, a new study indicated.
Data presented by Robert Lown, MD, of Royal Marsden Hospital and Anthony Nolan Graft Identification and Advisory Service, at the 2013 American Society of Hematology (ASH) Annual Meeting and Exposition indicated that there was no significant difference in the number of patients of non-white northern European decent and patients of white northern European descent who were able to successfully undergo transplant; however, a larger proportion of patients of non-white descent received cord blood or haploidentical transplants as opposed to HLA-matched transplants.
“The use of cord blood or haploidentical transplant has leveled the playing field for non-white northern European patients seeking transplants other than with an HLA-identical sibling,” Lown said. “We do not yet know, however, whether cure rate and survival with new donor sources, such as cord blood or haploidentical donors, are as good as unrelated donors.”
The majority of donors listed by unrelated donor registries are still of white northern European descent. Given the massive variation in tissue types between individuals, particularly individuals of different ethnicities, patients of ethnic minority descent have historically had difficulty finding donor matches. In fact, one study from 1996 to 2000 showed that suitable unrelated donor matches were only found in 36% of patients of non-white northern European descent compared with white patients.
With the recent addition of cord blood and haploidentical donors as a source of transplant, Lown and colleague sought to determine if patients of non-white northern European descent had better success at finding a suitable donor and getting to transplant. They enrolled 332 consecutive patients referred to the Anthony Nolan Graft Identification and Advisory Service; 25% of patients were of non-white northern European descent.
Although data showed that there was no statistically significant difference in the number of white and non-white patients reaching transplant (63.3% vs 56%; P = .185), several differences in the source of transplant were noted.
About 69% of white patients were able to find a 10/10 HLA-matched donor compared with only about 20% of non-white patients (P < .001); 9/10 HLA-matched donors were found for 96.3% of white patients compared with 61.4% of non-white patients (P < .001).
In contrast, non-white patients underwent significantly more cord blood transplants (21.3% vs 3.8%; P < .001) and haploidentical transplants (10.6% vs 1.3%; P < .001) compared with white patients.
The researchers also found that patients of non-white background had a slower time from first confirmatory typing request to identification of an unrelated donor (27 days vs 33.5 days; P = .002). The time from search request to transplant was also slower for patients of non-white background (110 days vs 132 days; P = .03); however, no difference in ethnic groups was found when the cumulative incidence of transplantation with death as a competing risk was considered.
“Time to transplant continues to improve from historical levels for all patients, but particularly for those of non-white northern European background,” Lown said.
Lown also pointed out that the results achieved in this study were done so with the use of an expert graft identification and advisory service, making widespread applicability uncertain. Using this service, Lown and colleagues were able to determine at an early stage whether they were going to find a suitable match for patients, allowing them to start pursuing cord blood or haploidentical matches at an earlier stage. Time to transplant may be increased at centers where this type of service is not available and cord blood or haploidentical transplant are needed.