Myeloma and Stem Cell Transplants

By Amanda Gardner, HealthDay News, March 14, 2007

Rather than receiving two transplants from themselves, researchers are now reporting that younger patients who have been diagnosed with myeloma survived longer if they received a stem cell transplant from themselves but then followed by one from a matched sibling.

Of the total who develop myeloma, a blood cancer, only a fraction would find this protocol to be a good treatment alternative.

"It's a good study and it gives important perspective, and it will be useful for some patients but it's a small minority of myeloma patients," said Dr. Marshall, executive vice president of research and medical programs at the Leukemia & Lymphoma Society.

The study was published in the New England Journal of Medicine’s March 15th issue. However, Dr. Marshall was not part of the study, which was led by University of Turin, Italy’s, Dr. Bruno.

Blood plasma cells are a type of white blood cell that is present in bone marrow, and Myeloma which is also known as multiple myeloma, is a cancer of these cells.

Newly diagnosed patients under the age of 65 typically receive high-dose chemotherapy followed by a transplant of their own stem cells.

"The transplant was rescuing the patients after life-threatening chemotherapy. You need that intensity to kill off the tumor, but it also kills off normal blood and immune-forming cells," Marshall explained. "The patient needs to be replenished."

However, allowing the disease a chance to recur, the transplanted cells do not always identify the cancer cells as foreign and attack them as they should.

But new immune cells attack and kill off the myeloma cells when the stem cells come from a compatible outside donor (such as a sibling). It creates as “graft-versus-myeloma” effect. In contrast to transplants using a patients own cells, patients receiving stem cell transplants from other donors experience longer remissions and lower relapse rates.

Allowing the disease to recur more readily, cell transplanted from the patient don’t attack the myeloma cells because they don’t recognize them as foreign.

162 patients aged 65 or younger were enrolled into this investigation. All of them had at least one sibling and had been recently diagnosed with myeloma.

Autologous stem cell rescue was performed on all the patients after being treated with chemotherapy. An allograft was performed on those patients who had a compatible sibling, they received radiation in addition to the siblings stem cells.

Two consecutive doses of the chemotherapy drug melphalan was administered to patients without a compatible sibling. The melphalan drug was followed by autologous stem cell rescue both times.

For those who had received a sibling stem cell transplant, the patients had a longer median rate of survival without recurrence and overall survival rate than the non-sibling transplant group. The median follow-up was conducted four years after the initial procedure.

Those receiving transplants only from themselves had survived an average of 54 months, but those patients that underwent the two different transplants survived an average of 80 months. Those that received autologous stem cell transplant recorded an event-free survival rate of 35 months, and the other group averaged 29 months.

In the double-autologous group, disease-free mortality was higher (43 percent vs. 7 percent). But overall, similar in both groups was death resulting from treatment.

After allografting, 36 percent of patients were in complete remission during a median follow-up of 38 months.

Of those receiving two autographts, more than half (54 percent) died.

Marshall said it is important to note that the study participants were all under 65. Of those suffering from myeloma, only 40 percent of patients are in that age group in “real life”. Even less, about 10 percent is the proportion of compatible siblings. Only 5 percent of the total who received the treatment experienced complete remission.

"For those people who are eligible, this is an interesting and important observation, and it may lead to moving from two auto transplants to an auto and an allo for those people who have a sibling donor," Marshall said. "For those who are eligible for this sort of treatment this is useful, but it's a minority of patients."

Marshall pointed out that in the intervening years since the study; a whole new series of myeloma drugs has emerged. The study was started more than 5 years ago.

"We really don't know what the very best approach would be today for someone of this age," Marshall said.