Purpose of review
Arsenic trioxide (ATO) has been shown to be the most effective single agent in acute promyelocytic leukaemia (APL) and has been approved for the treatment of relapsed patients both in the US and Europe. The role of ATO in front-line therapy of APL is under investigation.
Pilot studies using ATO with or without all-trans retinoic acid (ATRA) have been carried out in newly diagnosed APL patients with the aim to reduce the short and long-term toxic effects of chemotherapy and to improve clinical outcome. Especially in patients with non-high-risk APL, the ATRA + ATO approach allowed significant increase in event-free survival and overall survival rates compared to standard ATRA and chemotherapy. This has been demonstrated by pilot studies and, more recently, by a randomized comparative multi-centre study conducted in Italy and Germany.
The ATO + ATRA strategy for APL may provide the first paradigm of acute leukaemia curability by targeted agents and without chemotherapy. However, longer follow-up of available studies and independent confirmation of the Italian–German findings are awaited to firmly establish this paradigm. Finally, extension of this approach to other patient categories such as high-risk, elderly and children will need to be explored in the near future.