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Cell sources & donor selection

Research has changed what’s possible for patients without an 8/8 match

For patients who need hematopoietic cell transplantation (HCT), the degree of human leukocyte antigen (HLA) matching between the recipient and donor cell source used to have a significant impact on a patient’s outcomes for both unrelated and related HCT. While umbilical cord blood could be used effectively with a partial HLA match, historically HCT using peripheral blood stem cells (PBSC) or bone marrow from a related or unrelated donor required a full 8/8 match for the best outcomes.

That is changing with the use of post-transplant cyclophosphamide (PTCy) graft-versus-host disease (GVHD) prophylaxis, abatacept and other novel approaches.

Research has shown that patients can safely receive HCT using cells from partially matched donors, and their outcomes are in line with those of patients who received cells from a fully matched donor.
Transplant recipient Johanna with her donor Catherine

NMDP Donor for All

The NMDPSM Donor for All initiative includes a broad range of innovative research efforts to establish the safe and effective use of mismatched unrelated donors (MMUD), which significantly expands options for patients without an 8/8 donor.

Odds of finding a suitable HLA match have increased for all patients

MMUD research is critical for all patients but especially those with ethnically diverse ancestries. Donor registries like the NMDP RegistrySM and other international registries aren’t diverse enough to ensure every patient finds a fully matched donor, and registry recruitment alone won’t solve the problem. But science will.

Today, only 66% of patients have a full 8/8 HLA donor. Observational research from CIBMTR® (Center for International Blood and Marrow Transplant Research®), a research collaboration between the Medical College of Wisconsin® and NMDP, shows that using a 7/8 donor can increase the odds of finding a match to 84% for every patient. Those odds increase to nearly 100% for every patient when matches range from 5/8 to 8/8.

Match likelihoods for each race/ethnic group

Race/ethnic group match likelihood charts
 

A CIBMTR analysis of the NMDP Registry revealed HLA match likelihoods for five broad racial/ethnic groups from 5/8 to 8/8 HLA match levels for (a) donors for all ages and (b) donors age 35 or younger. Age is a factor in matching because research has shown younger donors are associated with better patient outcomes. The match likelihood was greater than 99% at a 5/8 or higher match level regardless of donor age or patient race/ethnicity. 

MMUD clinical trials show promising results

NMDP-sponsored clinical trials conducted through CIBMTR are showing promising results for patients who received MMUD HCT and PTCy GVHD prophylaxis.

The multi-center Phase II clinical trial known as 15-MMUD studied adult patients who received bone marrow from a MMUD. Patient outcomes up to three years post-HCT compared favorably to historical 8/8 HCT.

The second Phase II clinical trial, called ACCESS, studied adults who receive peripheral blood stem cells (PBSC) and pediatric patients who received bone marrow from MMUDs. Early results from a portion of one adult stratum are extremely promising at one year after transplant with:

  • Excellent overall survival (79%)
  • Significant GVHD-free, relapse-free survival (GRFS) (51%)
  • Low rates of severe acute and chronic GVHD (9%)
The pediatric stratum continues to enroll patients.

The third Phase II clinical trial, called OPTIMIZE, is enrolling adult patients who receive PBSCs from a MMUD and a reduced dose of PTCy.

Early referral for transplant consultation remains critical 


With the likelihood of finding a match increasing for all patients, high-resolution HLA typing and cytogenetic testing of the patient early after diagnosis and timely referral for a transplant consultation remain critical. NMDP offers resources and programs to help you understand the optimal timing for transplant consultation and to remove barriers to early HLA typing for your patients and their family members.

Transplant Consultation Timing Guidelines

Our transplant consultation guidelines, developed jointly with the American Society for Transplantation and Cellular Therapy, identify appropriate referral timing for a transplant consultation based on a patient’s disease characteristics.

Guidelines are available for adult and pediatric patients for hematologic malignancies and other disorders. Access the guidelines online or download the free mobile app.

NMDP HLA Today

Even with donor options expanding, finding a suitable related or unrelated donor can take time. Starting the process and finding a donor early can help your patient have HCT at the optimal time, which can lead to better outcomes.

The NMDP HLA Today program can help your hematology/oncology practice remove barriers to HLA typing. We offer HLA Today at no cost to your patients or your practice.