A study presented at the 2008 American Society for Hematology (ASH) meeting reports on a treatment called Tandem Auto/AlloHCT, a combination of stem cell transplants that uses cells from both the multiple myeloma patient and a donor.

In the study, newly diagnosed multiple myeloma patients first underwent autologous cell transplantation, a procedure in which a patient’s own stem cells are transplanted into his or her bone marrow. This was followed by non-myeloablative allotransplantation, which uses stem cells from a donor and is accompanied by a less aggressive conditioning regime than is typically given.

Seventy-three patients with stage 2-3 multiple myeloma received Tandem Auto/AlloHCT. All patients’ donor stem cells began to grow and create new blood cells. Overall response rate was 94 percent, with 68 percent of patients achieving complete remission, 7 percent very good partial remission, and 19 percent partial remission. Median time to progression was 4.6 years. 

However, 41 percent of patients experienced grade 2 to 4 acute graft-versus-host-disease (GVHD), which is a complication that occurs when the patient’s cells do not recognize donor cells and, in response, launch an immune attack. Five percent experienced grade 3 to 4 acute GVHD, and 54 percent had excessive chronic GVHD.

Mortality without relapse was 1 percent at 100 days, 10 percent at one year, and 16 percent at five years; most was related to GVHD and infection. A higher risk of relapse was associated with elevated levels of serum beta-2 microglobulin, a protein on the surface of cells, at diagnosis and an assessment of functional impairment of less than 90 percent at the start of allogeneic HCT.

This study shows that Tandem Auto/AlloHCT reduces the number of cancerous cells but leads to graft-versus-tumor effects. In addition to long-term disease control, the researchers conclude that GVHD and its complications remain key concerns.

Confirmation of the outcomes reported here and a comparison with a tandem autologous HCT study are anticipated upon completion of a trial that is currently underway.

For more information, see abstract 1130 from ASH 2008.