TY - JOUR A1 - Hanfstein, Benjamin A1 - Lauseker, Michael A1 - Hehlmann, Rüdiger A1 - Saussele, Susanne A1 - Erben, Philipp A1 - Dietz, Christian A1 - Fabarius, Alice A1 - Proetel, Ulrike A1 - Schnittger, Susanne A1 - Haferlach, Claudia A1 - Krause, Stefan W. A1 - Schubert, Jörg A1 - Einsele, Hermann A1 - Hänel, Mathias A1 - Dengler, Jolanta A1 - Falge, Christiane A1 - Kanz, Lothar A1 - Neubauer, Andreas A1 - Kneba, Michael A1 - Stengelmann, Frank A1 - Pfreundschuh, Michael A1 - Waller, Cornelius F. A1 - Spiekerman, Karsten A1 - Baerlocher, Gabriela M. A1 - Pfirrmann, Markus A1 - Hasford, Joerg A1 - Hofmann, Wolf-Karsten A1 - Hochhaus, Andreas A1 - Müller, Martin C. T1 - Distinct characteristics of e13a2 versus e14a2 BCR-ABL1 driven chronic myeloid leukemia under first-line therapy with imatinib JF - Haematologica N2 - The vast majority of chronic myeloid leukemia patients express a BCR-ABL1 fusion gene mRNA encoding a 210 kDa tyrosine kinase which promotes leukemic transformation. A possible differential impact of the corresponding BCR-ABL1 transcript variants e13a2 ("b2a2") and e14a2 ("b3a2") on disease phenotype and outcome is still a subject of debate. A total of 1105 newly diagnosed imatinib-treated patients were analyzed according to transcript type at diagnosis (e13a2, n=451; e14a2, n=496; e13a2+e14a2, n=158). No differences regarding age, sex, or Euro risk score were observed. A significant difference was found between e13a2 and e14a2 when comparing white blood cells (88 vs. 65 x 10(9)/L, respectively; P<0.001) and platelets (296 vs. 430 x 109/L, respectively; P<0.001) at diagnosis, indicating a distinct disease phenotype. No significant difference was observed regarding other hematologic features, including spleen size and hematologic adverse events, during imatinib-based therapies. Cumulative molecular response was inferior in e13a2 patients (P=0.002 for major molecular response; P<0.001 for MR4). No difference was observed with regard to cytogenetic response and overall survival. In conclusion, e13a2 and e14a2 chronic myeloid leukemia seem to represent distinct biological entities. However, clinical outcome under imatinib treatment was comparable and no risk prediction can be made according to e13a2 versus e14a2 BCR-ABL1 transcript type at diagnosis. (clinicaltrials.gov identifier: 00055874) KW - chronic myelogenous leukemia KW - polymerase-chain-reaktion KW - hybrid messenger RNA KW - chronic phase KW - cytogenetic response KW - no correlation KW - ABL gene KW - transcripts KW - breakpoint KW - survival Y1 - 2014 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-115476 SN - 1592-8721 VL - 99 IS - 9 ER - TY - JOUR A1 - Rinaldetti, Sébastien A1 - Pfirrmann, Markus A1 - Manz, Kirsi A1 - Guilhot, Joelle A1 - Dietz, Christian A1 - Panagiotidis, Panayiotidis A1 - Spiess, Birgit A1 - Seifarth, Wolfgang A1 - Fabarius, Alice A1 - Müller, Martin A1 - Pagoni, Maria A1 - Dimou, Maria A1 - Dengler, Jolanta A1 - Waller, Cornelius F. A1 - Brümmendorf, Tim H. A1 - Herbst, Regina A1 - Burchert, Andreas A1 - Janßen, Carsten A1 - Goebeler, Maria Elisabeth A1 - Jost, Philipp J. A1 - Hanzel, Stefan A1 - Schafhausen, Philippe A1 - Prange-Krex, Gabriele A1 - Illmer, Thomas A1 - Janzen, Viktor A1 - Klausmann, Martine A1 - Eckert, Robert A1 - Büschel, Gerd A1 - Kiani, Alexander A1 - Hofmann, Wolf-Karsten A1 - Mahon, François-Xavier A1 - Saussele, Susanne T1 - Effect of ABCG2, OCT1, and ABCB1 (MDR1) Gene Expression on Treatment-Free Remission in a EURO-SKI Subtrial JF - Clinical Lymphoma, Myeloma & Leukemia N2 - Within the EURO-SKI trial, 132 chronic phase CML patients discontinued imatinib treatment. RNA was isolated from peripheral blood in order to analyze the expression of MDR1, ABCG2 and OCT1. ABCG2 was predictive for treatment-free remission in Cox regression analysis. High transcript levels of the ABCG2 efflux transporter (>4.5 parts per thousand) were associated with a twofold higher risk of relapse. Introduction: Tyrosine kinase inhibitors (TKIs) can safely be discontinued in chronic myeloid leukemia (CML) patients with sustained deep molecular response. ABCG2 (breast cancer resistance protein), OCT1 (organic cation transporter 1), and ABCB1 (multidrug resistance protein 1) gene products are known to play a crucial role in acquired pharmacogenetic TKI resistance. Their influence on treatment-free remission (TFR) has not yet been investigated. Materials and Methods: RNA was isolated on the last day of TKI intake from peripheral blood leukocytes of 132 chronic phase CML patients who discontinued TKI treatment within the European Stop Tyrosine Kinase Inhibitor Study trial. Plasmid standards were designed including subgenic inserts of OCT1, ABCG2, and ABCB1 together with GUSB as reference gene. For expression analyses, quantitative real-time polymerase chain reaction was used. Multiple Cox regression analysis was performed. In addition, gene expression cutoffs for patient risk stratification were investigated. Results: The TFR rate of 132 patients, 12 months after TKI discontinuation, was 54% (95% confidence interval [CI], 46%-62%). ABCG2 expression (parts per thousand) was retained as the only significant variable (P=.02; hazard ratio, 1.04; 95% CI, 1.01-1.07) in multiple Cox regression analysis. Only for the ABCG2 efflux transporter, a significant cutoff was found (P=.04). Patients with an ABCG2/GUSB transcript level >4.5 parts per thousand (n=93) showed a 12-month TFR rate of 47% (95% CI, 37%-57%), whereas patients with low ABCG2 expression (<= 4.5 parts per thousand; n=39) had a 12-month TFR rate of 72% (95% CI, 55%-82%). Conclusion: In this study, we investigated the effect of pharmacogenetics in the context of a CML treatment discontinuation trial. The transcript levels of the efflux transporter ABCG2 predicted TFR after TKI discontinuation. (C) 2018 The Authors. Published by Elsevier Inc. KW - ABCG2 KW - Biomarker KW - CML KW - Imatinib KW - Prediction Y1 - 2018 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-226281 VL - 18 IS - 4 ER -