Stem cell transplantation in multiple myeloma (0, 1, or 2)

Autologous stem cell transplantation is now considered the standard of care in patients with multiple myeloma up to 65 years of age. Therefore, two questions have been recently addressed by cooperative groups: should autologous stem cell transplantation be offered to older patients, and is it possible to improve the results of autologous stem cell transplantation, especially with double autologous stem cell transplantation? The results of allogeneic transplantation remain disappointing, with a high transplant-related mortality rate, increasing the need to explore new strategies such as reduced-intensity conditioning.

A randomized Italian study confirms that two courses of intermediate-dose melphalan supported by autologous stem cell transplantation is superior to standard melphalan-prednisone even in patients aged 65 to 70. The Intergroupe Francophone du Myelome 94 (IFM94) trial shows that double transplantation is superior to single transplantation, at least in patients with less than 90% reduction of their M-component after one transplant. Several studies have addressed the issue of prognostic factors in the context of autologous stem cell transplantation. A prospective Dutch trial confirms poor results with T cell-depleted allogeneic transplantation prepared by a standard myeloablative regimen. The Seattle group, on the other hand, reports encouraging preliminary data with tandem auto/mini-allotransplantation.

The available results of randomized studies are in favor of tandem autologous transplantation. In the near future, ongoing studies will clarify the role of novel agents (thalidomide and its analogs, bortezomib) in the context of autologous stem cell transplantation and the place of tandem auto/mini-allotransplantation compared with tandem autologous transplantation.