[Arsenic trioxide, a new drug for the treatment of acute promyelocytic leukemia resistant to tretinoine].

Chinese clinical investigators in 1986 demonstrated the therapeutic potential of tretinoin and in 1992 that of arsenic trioxide in the treatment of acute promyelocytic leukaemia. These observations have been confirmed in European and American centres. In acute promyelocytic leukaemia there is an abnormal receptor for retinoids, designated PML/RAR-alpha. This receptor binds retinoids inadequately so that extra retinoids (in the form of tretinoin) are required to restart the normal cellular maturation, after which the promyelocytes can mature into granulocytes. Arsenic trioxide has a different mode of action, possibly related to its effects on sulfhydryl-rich proteins, resulting in dysplastic leukaemic promyelocytes, ending up in apoptotic cell death. Since 1990 tretinoin has been included worldwide in the treatment of acute promyelocytic leukaemia. The use of arsenic trioxide has not yet been included in treatment protocols for promyelocytic leukaemia in western medicine.