Use of differentiation-inducing agents in the myelodysplastic syndrome and acute non-lymphocytic leukemia.

The use of chemical agents that induce differentiation of malignant cells to normal cells has held great promise as an adjunct to standard chemotherapy. In vitro data has shown that 13-cis-retinoic acid can differentiate certain leukemia cell lines (e.g., HL-60) into stable granulocyte cells. In this study, oral 13-cis-retinoic acid was administered to four patients with the myelodysplastic syndrome (MDS) and to four patients with acute nonlymphocytic leukemia (ANLL). None of the MDS patients showed an hematologic response to the drug, while three of four ANLL patients responded with normalized peripheral blood counts. The side effects of the drug at 80-120 mg/d (dry skin, cheilitis, epistaxis) were self limiting.