Charles Craddock, CBE, FRCP (UK), FRCPath, DPhil, University of Birmingham, Birmingham, UK, provides an outline of the key findings from his study on combination therapy of lenalidomide and azacitidine in salvage therapy of relapsed acute myeloid leukemia (AML) patients post-allogeneic stem cell transplantation. This interview took place at the 5th International Congress on Controversies in Stem Cell Transplantation and Cellular Therapies (COSTEM) 2019, held in Berlin, Germany.