Roanoke Times
Copyright (c) 1995, Landmark Communications, Inc.
DATE: WEDNESDAY, March 27, 1991 TAG: 9103270074
SECTION: NATIONAL/INTERNATIONAL PAGE: A-8 EDITION: METRO
SOURCE: Associated Press
DATELINE: PHOENIX LENGTH: Medium
The new technique, still highly experimental, uses the common transplant drug cyclosporine to confuse disease-killing blood cells so they attack the patients' own body, believing it is foreign.
"Nobody really understands the phenomenon yet, except that it appears to have an anti-leukemia effect," said Dr. Robert B. Geller of the University of Chicago.
Before moving to Chicago, Geller worked on the technique at Johns Hopkins University, where it was developed and has been most extensively tested. He outlined the approach at a meeting of the American Cancer Society.
Bone-marrow transplants were once limited to young patients with blood cancers. But now they are being used in a variety of cancers in steadily older patients.
Initially, doctors attempted transplants in people who had cancers of the marrow tissue that makes blood cells. They killed the cancerous marrow with radiation and then replaced it with marrow taken from a closely related donor.
While this is still done, marrow transplants are now being performed in many other situations.
Sometimes doctors would like to give very high doses of chemotherapy to people with advanced tumors of other organs, such as the breast or brain, but cannot because the drugs damage the marrow.
Increasingly they are using self-transplants of the cancer patient's own marrow to skirt this limitation. They remove some bone marrow before treatment, blast the body with high doses of chemotherapy or radiation and then put back the marrow to restore the blood supply.
However, sometimes the marrow that is returned to the body contains traces of cancer. Doctors hope that cyclosporine, among other strategies, will help clean out this remaining cancer and cure the patient.
"It's a very attractive and novel approach to use the patient's own immune system to get rid of cancer," Dr. Richard J. O'Reilly of Memorial Sloan-Kettering Cancer Center in New York said.
When people receive marrow from relatives, the transplanted tissue often recognizes its new owner as foreign and attacks his body, causing a potentially life-threatening reaction called graft-vs.-host disease.
Using low doses of cyclosporine, a drug ordinarily used to prevent graft-vs.-host disease, doctors have found that they can actually stimulate a similar reaction when people get back their own bone marrow. In this case, however, the blood cells are confused into thinking their former home is foreign.
For reasons that no one yet understands, the blood cells go after particular types of tissue, and these include skin cells and cancer cells. The result is a mild form of graft-vs.-host disease that usually clears up by itself without serious side effects.
About 40 to 50 people worldwide have been treated this way for leukemia and lymphoma. Much more long-term follow up will be necessary before doctors can be sure it improves survival or will help people with other forms of cancer.
However, animal studies suggest that the technique can significantly improve the chances of escaping cancer.
by CNB