ORLANDO, Fla., Dec. 9 (UPI) -- Tandem bone marrow transplants -- first from the patient and then from a bone marrow-matched sibling -- may provide an effective treatment for the blood cancer called myeloma, according to cancer researchers.
Dr. David Maloney of the Fred Hutchinson Cancer Center in Seattle, Wash., told United Press International that the treatment is still "experimental and should only be used in the research setting." But he said his early results suggest that this piggyback approach to transplants can significantly reduce the risks of bone marrow transplant, while increasing survival in myeloma patients.
Forty-one patients received the tandem transplants. "Twenty-five patients had a complete response to treatment and 11 had a partial response," he said. He presented the findings Sunday at the American Society of Hematology meeting.
Twenty of the patients in the study had undergone chemotherapy and radiation treatment but had relapsed. Among those 20 patients "10 had a complete response to the tandem transplants and six had a partial response."
Dr. Stephen Mackinnon, a bone marrow transplant researcher from London, said the study is very significant because myeloma is "not curable with conventional methods." Moreover, he said that even conventional bone marrow transplantation has a low cure rate because "one in three patients are lost to transplant-related mortality."
Patients who receive bone marrow transplants from donors, called allogenic transplants, develop a serious type of transplant rejection called graft versus host disease, which causes the body's immune system to attack the newly transplanted bone marrow. This condition is serious and can be fatal, said Maloney. In his study protocol he only used bone marrow matched siblings as donors for the allogenic transplants.
But limiting donors to siblings may not be necessary, Maloney told UPI. He said he has used the same protocol with non-related donors in "four patients who requested the treatment. So far, they are doing fine." He said, however, that he cannot recommend using unrelated donors until a large study is conducted.
Graft versus host disease is not a concern for bone marrow transplants that use the patient's own marrow, called autologous transplants. But the autologous transplant process is also dangerous because it requires patients to undergo both chemotherapy and whole body radiation to destroy diseased cells.
Although the tandem transplant approach could be risky, Maloney said patients were willing to attempt the process, which takes as long as eight and a half months to complete, because myeloma "doesn't respond to chemotherapy."
Myeloma causes the body to keep producing more and more plasma cells. The unneeded plasma cells are all abnormal and are called myeloma cells. The myeloma cells collect in bone marrow and in the hard outer part of bones, forming tumors. About 13,500 new cases of myeloma are diagnosed in the United States each year and the disease is more common in African-Americans than in whites.