Reduced-intensity conditioning for acute myeloid leukemia: is this strategy correct.

Allogeneic stem cell transplantation for acute myeloid leukemia (AML) using reduced-intensity conditioning (RIC) is based on the strategy of attaining donor cell engraftment with immunosuppressive agents. This approach, which relies predominantly on donor effector cells for anti-leukemic or graft-versus-leukemia effect, is being used with increased frequency. Treatment-related mortality appears less with RIC than that observed with conventional myeloablative regimens. Available data support the fact that a myeloablative regimen is not required for successful engraftment and some patients appear to be cured of their disease. Despite the plethora of clinical reports, however, no prospective studies have been conducted that establish this procedure as the preferred option in AML. On the other hand, patients formerly excluded from a myeloablative procedure such as the 'elderly' and those with significant comorbid conditions, often may be RIC transplant candidates. By using prospective controlled clinical trials, we will determine whether these encouraging RIC data are applicable to a nonselect population of AML. The transplant community now is poised to design and complete investigations to ascertain the true role of RIC in the treatment of AML.