Retinoic Acid and Arsenic Trioxide vs Retinoic Acid and Chemotherapy in APL

As reported in the Journal of Clinical Oncology by Platzbecker et al, the final results of the Italian-German phase III APL0406 trial indicate that the combination of all-trans retinoic acid (ATRA) and arsenic trioxide (ATO [Trisenox]) is associated with better outcomes than standard ATRA plus chemotherapy in first-line treatment of low- or intermediate-risk acute promyelocytic leukemia (APL). The previously reported primary analysis of the study indicated noninferiority of ATRA-ATO in 2-year event-free survival. Francesco Lo-Coco, MD, of the University Tor Vergata, Rome, is the corresponding author of the Journal of Clinical Oncology article.

Improved Outcomes

In this open-label noninferiority trial, 266 patients were randomized between October 2007 and January 2013 to receive ATRA-ATO (n = 129) or ATRA-chemotherapy (n = 137). Among 263 patients evaluable for induction response, complete remission was achieved in 127 of 127 (100%) ATRA-ATO patients and 132 of 136 (97%) ATRA-chemotherapy patients (P = .12). After median follow-up of 40.6 months, 50-month rates were 97.3% vs 80% for event-free survival (P < .001), 1.9% vs 13.9% for cumulative incidence of relapse (P = .0013), and 99.2% vs 92.6% for overall survival (P = .0073).

Postinduction events in the ATRA-ATO group included relapse in 2 patients and 1 death. In the ATRA-chemotherapy group, findings included molecular resistance after third consolidation in 2 patients, 15 relapses, and 5 deaths. In addition, treatment-related neoplasms were noted in 2 ATRA-­chemotherapy patients.

The investigators concluded: “These results show that the advantages of ATRA-ATO over ATRA-chemotherapy increase over time and that there is significantly greater and more sustained antileukemic efficacy of ATRA-ATO compared with ATRA-chemotherapy in low- and intermediate-risk APL.”

The study was supported by the Gruppo Italiano Malattie Ematologiche dell’Adulto Foundation, Associazione Italiana Contro le Leucemie, Linfomi e Mieloma, Associazione Italiana per la Ricerca sul Cancro, and the German Federal Ministry of Education and Research. ■

Platzbecker U, et al: J Clin Oncol. July 11, 2016 (early release online).




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