Long-term outcome of 31 cases of refractory acute promyelocytic leukemia treated with compound realgar natural indigo tablets administered alternately with chemotherapy.

The aim of the present study was to investigate the long-term survival of patients with refractory acute promyelocytic leukemia (APL) that were administered alternately with compound realgar natural indigo tablet (CRNIT) treatment and chemotherapy. In total, 31 patients with refractory APL were administered with CRNIT treatment alternately with chemotherapy. The complete remission (CR) and relapse rates were estimated by bone marrow (BM) examination. The expression of the promyelocytic leukemia-retinoic acid receptor α (PML-RARα) fusion protein and the apoptosis rate in the retinoic acid (RA)-resistant NB4-R1 cell line administered with CRNIT treatment in vitro were measured by western blot analysis and flow cytometry, respectively. The patients were followed up for 12-60 months, with a median follow-up time of 43 months. The total continuous CR rate was 90.32% (28/31), and the duration of response was between 10.3 and 60 months (median, 42.4 months). The total relapse rate was 9.68% (3/31), and the median time of relapse was 13 months (range, 8-27 months). During the treatment with CRNITs, there was no evident BM depression and only limited side-effects were experienced. Additionally, in vitro cell molecular biology results revealed that CRNIT treatment resulted in a marked induction of apoptosis and degradation of the PML-RARα fusion protein. The present results revealed that CRNIT treatment in combination with chemotherapy is an effective and feasible therapy for the treatment of patients with refractory APL.