Primary refractory acute myeloid leukaemia - in search of better definitions and therapies.

The definition of primary refractory acute myeloid leukaemia is the failure to achieve a response after one or two cycles of induction. Given that there are many different strategies involving different doses of cytarabine and anthracyclines, which may or may not be equivalent, and as this is an area of unmet need with the potential for the development of new agents and strategies, uniform criteria for response have been described that need to be adhered to. The outcome of patients with chemoresistant disease is poor with only a proportion of patients salvaged by allogeneic stem cell transplantation. Progress in supportive care strategies and donor identification has enabled more of these patients to undergo unrelated donor transplantation. Novel strategies and new agents directed at the biology of the disease and the mechanisms of resistance are needed.