TOPLINE:

All-trans retinoic acid and arsenic trioxide (ATRA-ATO) combination therapy demonstrates superior event-free survival and lower molecular relapse rates compared to standard ATRA plus anthracycline-based chemotherapy (ATRA-CHT) in high-risk acute promyelocytic leukemia (APL). The ATRA-ATO regimen also shows a better safety profile with fewer serious treatment-emergent adverse events.

METHODOLOGY:

• A total of 133 eligible patients with newly diagnosed high-risk APL received either ATRA-ATO (n = 68) or ATRA-CHT (n = 65).
• Patients in the ATRA-ATO arm received 0.15 mg/kg ATO once daily and 45 mg/m² ATRA twice daily until complete remission, with two doses of 12 mg/m² idarubicin on days 1 and 3, followed by four cycles of ATRA-ATO consolidation therapy.
• Patients in the ATRA-CHT arm received 45 mg/m² ATRA twice daily and 12 mg/m² idarubicin once daily on days 1, 3, 5, and 7, followed by three cycles of chemotherapy-based consolidation and 2 years of maintenance therapy.
• The primary study endpoint was event-free survival at 2 years, with a median follow-up duration of 37 months (range, 1.7-88.6 months).

TAKEAWAY:

• Two-year event-free survival was 88% in the ATRA-ATO arm compared with 71% in the ATRA-CHT arm (hazard ratio [HR], 0.4; 95% CI, 0.17-0.92; P = .02).
• Molecular relapse occurred in 1.5% of patients receiving ATRA-ATO compared with 12.3% of those receiving ATRA-CHT (P = .014) at a median of 7.8 and 12.1 months from complete remission achievement.
• Serious treatment-emergent adverse events were reported in 32% of patients receiving ATRA-ATO compared to 68% of those receiving ATRA-CHT (P < .01).
• Complete remission rates were similar between groups, ie, 93% for the ATRA-ATO group compared with 91% for the ATRA-CHT group (P = .69).

IN PRACTICE:

“The results of the APOLLO trial support the use of ATO and ATRA for the treatment of newly diagnosed patients with high-risk APL,” the authors of the study wrote.

SOURCE:

The study was led by Uwe Platzbecker, MD, University Hospital Carl Gustav Carus and TU Dresden Faculty of Medicine in Dresden, Germany. It was published online in Journal of Clinical Oncology.

LIMITATIONS:

The study was discontinued prematurely due to slow recruitment during the COVID pandemic, resulting in a lower number of patients than originally planned. According to the authors, this may have affected the statistical significance of overall survival differences between treatment arms, and longer follow-up may be needed to fully explore this aspect.

DISCLOSURES:

The study was supported by the German Federal Ministry of Education and Research. Maria Teresa Voso received support from AIRC Foundation for Cancer Research in Italy. Teva Pharmaceuticals Europe B.V. provided financial support for clinical research organizations and supplied the investigational product free of charge.

This article was created using several editorial tools, including AI, as part of the process. Human editors reviewed this content before publication.