Current indications for reduced-intensity allogeneic stem cell transplantation.

Stem cell transplantation preceded by reduced-intensity conditioning (RIC) is based on the use of immunosuppressive agents as the sine qua non to ensure donor cell engraftment. It is a curative option for select patients suffering from haematological and non-haematological malignancies. The most beneficial results are observed when a full donor engraftment is achieved with 'tolerable' graft-vs-host disease (GVHD). To date, a vast amount of clinical data has been published, but in an uncontrolled manner. This review summarizes the currently known outcome of allogeneic transplants with RIC, with every disease category analysed separately. Unresolved problems include the optimal combination of immunosuppressive agents, the degree of infectious complications, and GVHD that may appear in some patients. Directions to overcome these complications are discussed. Despite the paucity of controlled clinical data, the current indications for RIC allogeneic transplantation are summarized based on the best-available phase II data.