Characteristics and outcome of patients with low-/intermediate-risk acute promyelocytic leukemia treated with arsenic trioxide: an international collaborative study.

The aim of this study was to characterize a large series of 154 patients with acute promyelocytic leukemia (median age, 53 years; range, 18-90 years) and evaluate real-life outcome after up-front treatment with arsenic trioxide and all-trans retinoic acid. All patients were included in the prospective NAPOLEON registry (NCT02192619) between 2013 and 2019. The acute promyelocytic leukemia was de novo in 91% (n=140) and therapy-related in 9% (n=14); 13% (n=20) of the patients were older than 70 years. At diagnosis bleeding/hemorrhage was present in 38% and thrombosis in 3%. Complete remission was achieved in 152 patients (99%), whereas two patients (1%) experienced induction death within 18 days after starting therapy. With a median follow-up of 1.99 years (95% confidence interval: 1.61-2.30 years) 1-year and 2-year overall survival rates were 97% (95% confidence interval: 94-100%) and 95% (95% confidence interval: 91-99%), respectively. Age above 70 years was associated with a significantly shorter overall survival (P<0.001) compared to that of younger patients. So far no relapses have been observed. Six patients (4%) died in complete remission at a median of 0.95 years after diagnosis (range, 0.18-2.38 years). Our data confirm the efficiency and durability of arsenic trioxide and all-trans retinoic acid therapy in the primary management of adults with low-/intermediate-risk acute promyelocytic leukemia in the real-life setting, irrespective of age.

[Very Severe Differentiation Syndrome in Low Risk Acute Promyelocytic Leukemia - A Peril of Differentiating Therapy]. / Sehr schweres Differenzierungssyndrom bei Niedrigrisiko akuter Promyelozytenleukämie ­ eine Tücke der differenzierenden Therapie.

History, examinations and diagnosis A young patient consulted the hospital because of spontaneous hematomas. The combination of pancytopenia and coagulopathy in the blood and the proving cytogenetic and moleculargenetic examinations of the bone marrow lead to the diagnosis of low-risk acute promyelocytic leukemia (APL). Therapy and clinical course During the combination therapy with ATRA and ATO, the patient developed a severe differentiation syndrome and hyperleukocytosis. Management of the condition was only possible due to clinical expertise and massive substitution of blood products and clotting factors. Conclusion The case illustrates the difficulty and dangers of APL induction therapy even with a favorable initial clinical presentation despite the generally low toxicity of new therapies.