Patients with high-risk myelodysplastic syndrome (MDS) and acute myeloid leukemia (AML), who cannot be offered curative treatment, have a poor prognosis with a median survival of 11.5 months. There is currently only one registered drug that has been shown to prolong survival in this patient group; the hypomethylating agent azacitidine (also known as 5-azacytidine or Vidaza®). The treatment is not curative, but increases the median survival to approximately two years. The dominant cause of death is progressive disease, and there is a huge need for new treatment options.