Grimwade and his colleagues tried the test (which is not yet approved for use in the United States) on more than 2,500 blood samples obtained from nearly 350 patients with the NPM1 mutation.
At the same time, standard genetic testing was conducted on almost 275 other blood samples.
“Our key finding,” said Grimwade, “is that the MRD test — which is pretty cheap and easy to apply — provides a much more powerful predictor of patient outcome in this group of AML patients as compared to genetic profiling of the tumor sample, which is a much more expensive test.”
The investigators said the test found evidence of a high risk for disease recurrence in 15 percent of the tested samples, following a second round of chemotherapy. Finding that evidence suggested a more than 80 percent chance of disease recurrence after three years. This compared with just a 30 percent risk of disease recurrence among the other AML patients.
The study findings were published in the Jan. 21 issue of the New England Journal of Medicine.
In the end, Grimwade said his team concluded that the MRD test “provides a far stronger predictor of patient outcome than the standard tests used to determine whether a patient should have a stem cell transplant or not. We also show that serial MRD testing after completion of therapy can pinpoint precisely which patients are destined to relapse, allowing the opportunity for early intervention preventing full-blown relapse from occurring.”
Dr. Michael Burke, author of an accompanying editorial in the journal, said the finding is important given that “a relapse in AML is almost certain death.”
“And this study,” he added, “points out that you can actually follow very, very low levels of leukemia using this NPM1 marker, and that those patients in whom it disappears after a couple of cycles of chemo will do exceedingly well. They don’t need a bone marrow transplant. But those with high levels of this marker after two rounds of chemo fare terribly and really should go on to have the transplant. So, this is very encouraging news.”
Burke is director of the Leukemia Lymphoma Program at the Children’s Hospital of Wisconsin in Milwaukee.
More information
There’s more on acute myeloid leukemia at the U.S. National Cancer Institute.
SOURCES: David Grimwade, M.D., Ph.D., professor, molecular haematology, department of medical and molecular genetics, Cancer Genetics Lab, King’s College London, England; Michael Burke, M.D., associate professor, department of pediatrics, division of hematology and oncology, blood and marrow transplantation, Medical College of Wisconsin, and director, Leukemia Lymphoma Program, Children’s Hospital of Wisconsin, Milwaukee; Jan. 21, 2016, New England Journal of Medicine, online.
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