Imperfect match may be just as good as perfect match for blood cancers

A scanning electron 

microscope image 

from normal circulating 

human blood. – Wikipedia

CANCER DIGEST – Oct. 7, 2015 – Using a half-matched donor bone marrow transplant may be just as good as a full match for treating blood cancers like leukemia and lymphomas, new research shows.

In the first study to compare the gold standard full-match to a half-match transplant using an identical protocol, researchers at the Thomas Jefferson Kimmel Cancer Center have shown three years after transplant approximately 70 percent of the patients in both groups were still alive and cancer free.

The finding could be a major advance for minorities, and others without good access to full-match donors. The study was published in the journal Biology of Blood and Marrow Transplantation.

The study compared outcomes of patients with half-matched, or haploid donor marrow cells transplanted using a two-step protocol with patients who had full-matched donors receiving the same two-step approach. Three years after transplant approximately 70 percent of the patients in both groups were still alive and cancer free. 

Overall more patients with half-matched donors experienced graft-vs-host disease (40%) than those in the full-match group (8%). Graft-vs-host disease occurs when the donor immune cells attack the patient cells as if they are “foreign.” Symptoms range from skin rash to persistent nausea and vomiting.

The two-step transplant protocol developed at Jefferson staggers the administration of cancer-killing T cells with marrow-building immune system cells. Patients first receive the T cells, followed by the drug cyclophosphamide, that helps keep those cell from becoming over reactive. The rest of the marrow cells are then given next. In preliminary results presented at the American Society of Bone and Marrow Transplantation meeting in 2014, the two-step protocol resulted in of donor cells taking hold 3-4 days earlier than with a one-step procedure. 

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