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Leveling the playing field for patients with mismatched donors

In the perfect world, every patient who needs a blood or marrow transplant for cancer would have a perfect matched related donor. That’s not the case. Second best would be an HLA-matched (8/8) unrelated donor. Unfortunately, that’s not always the case either, with ethnically diverse patients less likely to have an 8/8 donor available. In the past, the lack of a fully matched donor increased patients’ risk of acute graft-versus-host-disease (GVHD) and death due to complications from the transplant (transplant-related mortality) or overall survival. And that’s not fair.

Is it possible to level the playing field for those patients who can’t find fully matched donors and must resort to using a mismatched unrelated donor (MMUD) (7/8)? The answer is yes.

Researchers decided to build on results from a multicenter clinical trial completed in 2021. That trial showed that adding the drug abatacept to the standard care treatment for GVHD reduced acute forms of that condition. The effect was most pronounced in the 7/8 MMUD patient group — and accompanied by a reduction in transplant-related mortality and overall survival.

The researchers then asked if abatacept could completely level the playing field between patients using a matched unrelated donor (MUD) and MMUD. In other words, could abatacept make 7/8 = 8/8?

A closer look

A subsequent analysis of the clinical trial data set out to determine just that by comparing the outcomes of patients who had a transplant with a MUD and standard care treatment to patients who had a transplant with a MMUD who received standard care plus abatacept.

The analysis showed no differences in the two groups in rates of transplant-related mortality or overall survival. In fact, severe acute GVHD was significantly lower in the MMUD group compared to the MUD group.

What does this information tell researchers?

They can conclude that adding abatacept to standard care makes outcomes after transplant with a MMUD more similar to those using a MUD. For patients, that means their risks of severe acute GVHD and transplanted-related mortality are lower with abatacept without increasing their risk of the disease coming back.

It’s important to note that the group of patients studied was relatively small, and further research is needed. However, the transplant community can be confident that using a one-size-fits-all approach to GVHD prevention isn’t optimal. Patients with mismatched donors need a little something extra — in this case, abatacept.

This study provides one more tool to make sure all patients have access to a donor and can attain acceptable transplant outcomes whether the donor is fully matched or not.

 Learn more by reviewing a comprehensive analysis and description of the study.

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