SEATTLEA two-stage procedure that combines high-dose chemotherapy with autologous stem cell transplantation (SCT) with an immunosuppressive (but not myeloablative) allogeneic SCT in multiple myeloma improves complete response rate and decreases treatment-related mortality.
In a plenary presentation at the 43rd Annual Meeting of the American Society of Hematology, David G. Maloney, MD, PhD, presented data for 41 patients treated with this approach. "The reduced mortality allows treatment of older patients. We feel our method should now be studied in comparison to conventional autografting for the treatment of patients with myeloma," said Dr. Maloney, who is an associate member of the Fred Hutchinson Cancer Research Center in Seattle.
Treatment-Related Mortality an Issue
In introducing this paper, Stephen Mackinnon, MD, pointed to treatment-related mortality as a major flaw in conventional transplants. "We are still losing one out of three of our transplant patients to transplant-related causes. In addition, conventional transplants are generally not applicable to older patients, because age is associated with increased risk. That is a problem, as most multiple myeloma patients are elderly." Dr. Mackinnon is a consultant in hematology at University College in London.
The lower-intensity regimen Dr. Maloney used to prepare patients for the allogeneic SCT is myelosuppressive rather than myeloablative. It has limited antitumor efficacy but is immunosuppressive enough to permit transplant engraftment, according to Dr. Mackinnon. The main difference compared to conventional regimens is in the use of low-dose total-body irradiation.
Dr. Maloney said that although myeloablative allogeneic SCT is potentially curative for myeloma (due to the graft-vs-myeloma effect), his group has been concerned about high transplant-related mortality due to regimen-related toxicities and graft-vs-host disease. "The alternative of high-dose therapy with autologous stem cell rescue induces cytoreduction of the disease with a low transplant-related mortality, but nearly all patients eventually relapse or develop disease progression," he said.
Therapy Could Be Curative