Many years ago, researchers tested a theory of using two unrelated units of cord blood to produce an increased volume of stem cells, which would decrease the engraftment time frame in adults suffering from blood disorders. The newly expanded procedure proves promising results and will soon begin human clinical trials.
A team of researchers from the MD Anderson Cancer Center in Houston has come up with a new way to make stem cell transplants more effective in patients with leukemia, lymphoma and other blood cancers and disorders. The study, whose findings were published last week in the New England Journal of Medicine, is the first of its kind to show favorable results in manipulating one batch of stem cells in patients who undergo a double cord blood transplant. The promising results have paved the way for expanding the study from one site to an international, multicenter clinical trial.
University Hospitals Seidman Cancer Center is poised to become one of those sites. Between 15 and 25 patients will be enrolled, said Dr. Marcos de Lima, lead study author who joined UH in the fall to become section chief of hematologic malignancies and bone marrow transplantation at Seidman and professor of medicine at Case Western Reserve University School of Medicine. With study sites opening up elsewhere in the United States and in Europe, several hundred patients will be able to take part in the trial, said de Lima. He said he hopes enrollment will start within the next year.
Cord blood, which is filled with adult stem cells similar to those found in bone marrow, is extracted from an umbilical cord and placenta shortly after a baby is born. Transplanting cord blood instead of bone marrow or peripheral blood has several advantages, among them that the cord blood doesn’t have to be a perfect match for a patient. That opens up the number of potential matches that are available for patients, especially those who are ethnic minorities. But among the limitations were the time it took for donor cells to begin making new blood cells, called engraftment, and the relatively small amount of cells that can be obtained from one cord blood unit — a problem for adult patients.
The first double cord blood transplants using two unrelated units of cord blood, designed to make transplantation more effective in adults, were conducted more than a dozen years ago. The ability to produce a higher volume of stem cells from the two transplanted units still did not solve the problem of the length of time from infusion to engraftment. “The longer you go without red blood cells, white blood cells and platelets, the more trouble you have,” de Lima said. All of those things are essential to ward off infection, bleeding, and anemia. To get around that hurdle, the MD Anderson team decided to see if they could make more of the cord blood cells in the lab in conditions that mimic that of bone marrow. One unit was transplanted unchanged, while the second unit was “expanded” in the lab — before transplant — using a type of cell found in bone marrow called mesenchymal stromal cell.
The study, which opened in 2007 and lasted for three years, enrolled 31 patients at MD Anderson, all of whom received two cord blood units with the new treatment. An additional 140 patients from MD Anderson and elsewhere also received two units of unmanipulated cord blood, and were the control group. The result of the expansion treatment was quicker engraftment, compared to other patients treated with the more traditional double cord blood transplant method. The most unexpected study outcome, de Lima said, was the reduction in time it took to resume production of platelets, a key in protecting against excessive bleeding.
“Traditionally, platelets are a big problem,” said de Lima, adding that patients typically have to undergo numerous transfusions. With the new method, “We saw much more consistent, solid [development], and people needed less transfusion. That was a pleasant surprise,” he said.
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