Hematopoietic stem cell transplantation in the second or later complete remission in acute promyelocytic leukemia initially treated with all-trans retinoic acid

Despite the use of all-trans retinoic acid (ATRA) as the first-line treatment for acute promyelocytic leukemia (APL), relapse occurs in about 20% of cases. Most relapsing APL patients can achieve second remission (CR2) following ATRA combined with chemotherapy or arsenic trioxide. Stem cell transplantation (SCT) has been widely adopted in CR2, but optimal SCT (auto- or allo-SCT) remains controversial. We analyzed the outcomes for 8 APL patients initially treated using ATRA, who relapsed, achieved CR2 and underwent auto-SCT (n = 4) or allo-SCT (n = 4). The mean age of patients who underwent allo-SCT was 39 years. Minimal residual disease (MRD) just prior to SCT was positive in 1 patient and negative in 3. Engraftment was achieved in all patients, but 2 patients died of transplantation-related complications within 6 months. Complete molecular remission has been maintained in the remaining 2 patients. The mean age of patients who underwent auto-SCT was 48 years. MRD just prior to SCT was negative in all 4 patients. Complete molecular remission has been maintained in all 4 patients (mean follow-up, 3 years 9 months). The results for auto-SCT are favorable in patients with MRD-negative APL.