Leukemia, Lymphoma Patients Sought to Test 'Mini-Transplants'

LINCOLN - The University of Nebraska Medical Center needs 40 cancer patients to help test a new "mini-transplant" procedure researchers think will be far less toxic than traditional allogenic bone-marrow transplants.

The technique developed by Drs. Steven Pavletic and Greg Bociek aims to reduce the risk and side effects of graft-versus-host disease - a potentially fatal side effect of allogenic transplants. In traditional transplants, bone marrow from related and unrelated donors is used to create a new, cancer-free immune system in the patient. The UNMC technique transplants bone marrow only from related donors, and uses much lower doses of radiation and very mild chemotherapy. Bone marrow is the source of the body's white blood cells, the immune system that fights infection.

Think of it this way: You've got two overlapping circles, with the patient standing in the middle of the overlap. One circle represents "graft vs. cancer," the good outcome doctors are looking for where donor bone-marrow cells attack the patient's cancer. The other circle represents "graft vs. host," the bad outcome doctors hope to avoid where donor cells attack other tissues in the patient's body. By carefully balancing transplanted cells, radiation and drug treatment, the UNMC doctors hope to have the patient touching as much as possible of the good circle and as little as possible of the bad circle.

"Our protocol is designed to be very non-aggressive," Pavletic said.

The UNMC approach also involves a new use for an old leukemia drug, pentostatin. "The drug plays an important role in suppressing the patient's immune cells during the transplant process," Pavletic said. This is another key thing to understand about the mini-transplants. Previously, doctors have used heavy doses of radiation and chemotherapy to essentially destroy a patient's immune system, so there will be a clear path for the foreign donated bone-marrow cells to do their work and not be rejected by the patient's own immune system. With mini-transplants, it's only necessary to suppress the patient's immune system -- putting him or her in far less danger of complications.

Those eligible for the study include patients who are responding to standard treatments, but whose disease is at a high risk of coming back; patients older than 60; those who can't tolerate high doses of radiation and chemotherapy; and those whose cancer returned after an autologous stem-cell transplant.

"We use this therapy with patients who otherwise have very little hope. Instead of no chance for survival, we hope we can achieve a 30 to 50 percent cure rate. We want to find something for these patients," Pavletic said.

For progress on cancer therapies to continue, Pavletic said, people need to continue to enroll in clinical trials like the one UNMC plans. He cited the Food and Drug Administration's recent unusually rapid approval of Gleevec, an oral therapy for some patients with chronic myeloid leukemia. Pavletic was the principal investigator for UNMC's portion of the national Gleevec study.

"The approval of Gleevec in two years was the most rapid FDA approval ever," Pavletic said. "This is one of the reasons why it is important for patients to participate in clinical trials.

"If we didn't have patients, we wouldn't have any of this information yet. Some people have reservations about participating in clinical trials like 'I'm going to be a guinea pig,' and so on. It's natural to have these reservations. But all these trials are therapeutic.

"The bottom line is we are doctors. We don't offer a trial if we think there is something better."

For more information about the study, call Karen Taylor at (402) 559-6729.

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This story originally appeared in Nebraska StatePaper on