Management of relapse in acute promyelocytic leukaemia treated with up-front arsenic trioxide-based regimens

The standard of care for patients with acute promyelocytic leukaemia (APL) relapsing after front-line treatment with arsenic trioxide (ATO)-based regimens remains to be defined. A total of 67 patients who relapsed after receiving ATO-based up-front therapy and were also salvaged using an ATO-based regimen were evaluated. The median (range) age of patients was 28 (4-54) years. While 63/67 (94%) achieved a second molecular remission (MR) after salvage therapy, three (4 center dot 5%) died during salvage therapy. An autologous stem cell transplant (auto-SCT) was offered to all patients who achieved MR, 35/63 (55 center dot 6%) opted for auto-SCT the rest were administered an ATO + all-trans retinoic acid maintenance regimen. The mean (SD) 5-year Kaplan-Meier estimate of overall survival and event-free survival of those who received auto-SCT versus those who did not was 90 center dot 3 (5 center dot 3)% versus 58 center dot 6 (10 center dot 4)% (P = 0 center dot 004), and 87 center dot 1 (6 center dot 0)% versus 47 center dot 7 (10 center dot 3)% (P = 0 center dot 001) respectively. On multivariate analysis, failure to consolidate MR with an auto-SCT was associated with a significantly increased risk of relapse [hazard ratio (HR) 4 center dot 91, 95% confidence interval (CI) 1 center dot 56-15 center dot 41; P = 0 center dot 006]. MR induction with ATO-based regimens followed by an auto-SCT in children and young adults with relapsed APL who were treated with front-line ATO-based regimens was associated with excellent long-term survival.