Open Access

Richard Friedrich Schlenk, Michael Lübbert, Axel Benner, Alexander Lamparter, Jürgen Krauter, Wolfgang Herr, Hans Martin, Helmut Rainer Salih, Andrea Kündgen, Heinz August Horst, Peter Brossart, Katharina Götze, David Nachbaur, Mohammed Wattad, Claus-Henning Köhne, Walter Fiedler, Martin Bentz, Gerald Wulf, Gerhard Held, Bernd Hertenstein, Hans Salwender, Verena I. Gaidzik, Brigitte Schlegelberger, Daniela Weber, Konstanze Döhner, Arnold Ganser, Hartmut Döhner

• The aim of this clinical trial was to evaluate the impact of all-trans retinoic acid (ATRA) in combination with chemotherapy and to assess the NPM1 status as biomarker for ATRA therapy in younger adult patients (18-60 years) with acute myeloid leukemia (AML). Patients were randomized for intensive chemotherapy with or without open-label ATRA (45 mg/m2, days 6-8; 15 mg/m2, days 9-21). Two cycles of induction therapy were followed by risk-adapted consolidation with high-dose cytarabine or allogeneic hematopoietic cell transplantation. Due to the open label character of the study, analysis was performed on an intention-to-treat (ITT) and a per-protocol (PP) basis. One thousand one hundred patients were randomized (556, STANDARD; 544, ATRA) with 38 patients treated vice versa. Median follow-up for survival was 5.2 years. ITT analyses revealed no difference between ATRA and STANDARD for the total cohort and for the subset of NPM1-mutated AML with respect to event-free (EFS; p = 0.93, p = 0.17) and overall survival (OS; p = 0.24 and p = 0.32, respectively). Pre-specified PP analyses revealed better EFS in NPM1-mutated AML (p = 0.05) and better OS in the total cohort (p = 0.03). Explorative subgroup analyses on an ITT basis revealed better OS (p = 0.05) in ATRA for genetic low-risk patients according to ELN recommendations. The clinical trial is registered at clinicaltrialsregister.eu (EudraCT Number: 2004-004321-95).