Original published date: 8/29/2024

Joey was in his early 20s when he joined the NMDP Registry^SM. He anxiously awaited the call that he was a match for a patient who needed a blood stem cell transplant.

That call finally came when Joey was 27 years old—more than four years after he’d joined the registry. “I was really starting to think, ‘Maybe I’m just not going to be a match to anybody.’ So, I was ecstatic when I actually got the call,” he said.

If a younger donor had also been a match for the patient, Joey might not have gotten that call. That’s because a donor’s age is an important factor that a blood stem cell transplant team looks at when they’re choosing a donor.

Studies from CIBMTR® (Center for International Blood and Marrow Transplant Research®) and global registries have consistently found that younger blood stem cell donors are associated with better patient survival. For years, the youngest available donor on the registry has been considered the best donor.

New research is changing that thinking.

“Younger donors are better, but the question remains how young the donor should be to have a good outcome,” said Steven Devine, MD, chief medical officer for NMDP^SM and senior scientific director for CIBMTR.

The answer is important. Patients who need a blood stem cell transplant for a cancerous or non-cancerous disease would have a higher likelihood of having an available optimal donor if the donor choice were expanded beyond the youngest donors.

Researchers from CIBMTR—a research collaboration between the Medical College of Wisconsin® and NMDP—used an advanced machine learning technique to better understand the donor characteristics, such as donor age, that impact a patient’s overall survival and event-free survival.

An earlier study that defined the best donor as the youngest donor available on a search of the NMDP Registry only looked at patients’ overall survival at one year after transplant.

This study analyzed much newer patient outcomes data and a large number of donor-recipient pairs. Researchers looked at overall survival and event-free survival for up to three years after transplant. Event-free survival included survival without:

• Relapse (the disease coming back)
• Graft failure or rejection (the patient’s body did not accept the donor’s cells)
• Moderate or severe graft-versus-host disease (a complication after transplant where the donor’s cells attack the patient’s healthy cells)

The donor’s age was more important for survival than the donor’s sex. But the donor’s sex was important for event-free survival, with male donors leading to better event-free survival than female donors. That means if the age difference between a male and female donor is minimal, a male donor is preferred.

The study is important because it shows donors aged 18 to 30 years old result in similar outcomes.

“These results should allow for greater flexibility in choosing among donors and could also help address issues related to donor availability,” Dr. Devine shared.

Expanding the donor choice beyond the youngest donors increases the likelihood a patient will have an available optimal donor for transplant. Donors like Joey.

Joey was excited when he got the call to donate, but he was also a little nervous. Not about the donation itself but what that donation meant.

Joey’s blood stem cell donation at the NMDP Seattle Collection Center went smoothly. Just after his donation, he shared this message for the patient who would receive his blood stem cells: “I hope that these (blood) stem cells are able to help you get back to a normal life and spend more time with your family or your friends or doing what you love. And I really hope that I was able to help. I wish you nothing but the best.”

NMDP is committed to opening the door to treatment for all patients who need a blood stem cell transplant. Research—like the donor age analysis—is critical in achieving this goal.

Discover how NMDP is investing in groundbreaking research that will create meaningful change and bring life-saving treatments to more patients.