Allogeneic bone marrow or peripheral stem cell transplant

Evidence (allogeneic bone marrow or peripheral SCT):

Many patients are not young enough or healthy enough to undergo these intensive approaches. A definite graft-versus-myeloma effect has been demonstrated, including regression of myeloma relapses after the infusion of donor lymphocytes.[114]

Favorable prognostic features included:

Myeloablative allogeneic SCT has significant toxic effects (15%–40% mortality), but the possibility of a potent and possibly curative graft-versus-myeloma effect in a minority of patients may offset the high transplant-related mortality.[114-116] In one anecdotal series of 60 patients who underwent allogeneic SCT, six of the patients relapsed between 6 and 12 years, suggesting that late relapses still occur with this type of consolidation.[117]

The lower transplant-related mortality from nonmyeloablative approaches has been accompanied by a greater risk of relapse.[116] Since the introduction of lenalidomide and bortezomib, a trial exploring donor versus no donor comparison of autologous SCT versus autologous SCT and nonmyeloablative allogeneic SCT in 260 untreated patients showed no difference in PFS or OS.[118][Level of evidence C1] This result contrasted with two older trials (before introduction of lenalidomide and bortezomib), which suggested improvement of PFS and OS with a sibling donor.[109,119][Level of evidence C1]

Six clinical trials compared the outcomes of patients receiving tandem autologous transplant with those of patients receiving a reduced-intensity autologous SCT after autologous transplant. Patients were assigned to the latter treatments based on the availability of an HLA-matched donor. Two meta-analyses of these data showed that although the complete remission rate was higher in patients undergoing reduced-intensity autologous SCT, OS was comparable because of an increased incidence of nonrelapse mortality with allogeneic transplant.[111,112][Level of evidence A1] Anecdotal long-term survivals have been reported for patients with therapy-related MDS, AML, acute lymphoblastic leukemia, or chronic myelomonocytic leukemia treated with allogeneic SCT.[120]