Relapsed APL patient with variant NPM-RARα fusion responded to arsenic trioxide-based therapy and achieved long-term survival

The t(5;17)/NPM-RAR alpha is the second variant chromosomal translocation in acute promyelocytic leukemia (APL) to be characterized and also the second most plentiful variant translocation. So far, there is a lack of information on the effectiveness of arsenic trioxide (ATO) in relapsed APL with variant RAR alpha chimera including t(5;17)/NPM-RAR alpha. We report here a long-term survived APL patient with variant NPM-RAR alpha fusion who relapsed four times and each time responded well to ATO or ATO-based re-induction therapy. The patient had received a total of more than 3,500 mg of ATO, but showed no obvious arsenic-related toxicities. This case illustrates the long-term efficiency and safety of ATO-based therapy not only in newly diagnosed APL, but also in relapsed APL including those with variant translocations.