Re‐induction of complete remission with a new synthetic retinoid, Am‐80, for relapse of acute promyelocytic leukaemia previously treated with all‐trans retinoic acid

Two patients with relapsed acute promyelocytic leukaemia previously treated with all-trans retinoic acid (ATRA), were treated with a new synthetic retinoid, Am-80. In both patients pancytopenia gradually resolved without an increase in leukaemic cells, and differentiation of leukaemic cells was observed morphologically in bone marrow. Without the use of anti-leukaemic agents, both cases achieved complete remission (CR) on days 52 and 38 of treatment, respectively. On the day of CR, PML gene rearrangement and the t(15;17) translocation disappeared, though PML-RAR alpha chimaeric messenger RNA was still detected by reverse transcriptase polymerase chain reaction. Both patients then received conventional chemotherapy for consolidation of CR. These clinical experiences suggest that Am-80 may be an active agent for APL patients who have relapsed from ATRA-induced remission.