title: Phospho-CRKL monitoring for the assessment of BCR-ABL activity in imatinib-resistant chronic myeloid leukemia or Ph+ acute lymphoblastic leukemia patients treated with nilotinib.
abstract: Actual BCR-ABL kinase inhibition in vivo as determined by phospho-CRKL (pCRKL) monitoring has been recognized as a prognostic parameter in patients with chronic myelogenous leukemia treated with imatinib. We report a biomarker sub-study of the international phase I clinical trial of nilotinib (AMN107) using the established pCRKL assay in imatinib-resistant chronic myeloid leukemia or Ph+ acute lymphoblastic leukemia. A minimum dose (200 mg) required for effective BCR-ABL inhibition in imatinib resistant/intolerant leukemia was determined. The pre-clinical activity profile of nilotinib against mutant BCR-ABL was largely confirmed. Substantial differences between peripheral blood baseline pCRKL/CRKL ratios were observed when comparing chronic myeloid leukemia with Ph+ acute lymphoblastic leukemia. Finally, rapid BCR-ABL-reactivation shortly after starting nilotinib treatment was seen in acute lymphoblastic leukemia patients with progressive disease carrying the P-loop mutations Y253H, E255K, or mutation T315I. Monitoring the actual BCR-ABL inhibition in nilotinib treated patients using pCRKL as a surrogate is a means to establish effective dosing and to characterize resistance mechanisms against nilotinib.
authors: III. Medizinische Klinik, Medizinische Fakultät Mannheim, Universität Heidelberg, Theodor-Kutzer-Ufer 1-3 68167 Mannheim, Germany. paul.larosee@med3.ma.uni-heidelberg.de
authors: Paul
authors: P
authors: La Rosée
authors: Susanne
authors: S
authors: Holm-Eriksen
authors: Heiko
authors: H
authors: Konig
authors: Nicolai
authors: N
authors: Härtel
authors: Thomas
authors: T
authors: Ernst
authors: Julia
authors: J
authors: Debatin
authors: Martin C
authors: MC
authors: Mueller
authors: Philipp
authors: P
authors: Erben
authors: Anja
authors: A
authors: Binckebanck
authors: Lydia
authors: L
authors: Wunderle
authors: Yaping
authors: Y
authors: Shou
authors: Margaret
authors: M
authors: Dugan
authors: Ruediger
authors: R
authors: Hehlmann
authors: Oliver G
authors: OG
authors: Ottmann
authors: Andreas
authors: A
authors: Hochhaus
mesh_terms: D048868:Adaptor Proteins, Signal Transducing / Q000737:chemistry*; D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000970:Antineoplastic Agents / Q000494:pharmacology*; D001549:Benzamides; D005260:Female; D016044:Fusion Proteins, bcr-abl / Q000378:metabolism*; D015973:Gene Expression Regulation, Leukemic; D006801:Humans; D000068877:Imatinib Mesylate; D015464:Leukemia, Myelogenous, Chronic, BCR-ABL Positive / Q000188:drug therapy* / Q000378:metabolism; D008297:Male; D008875:Middle Aged; D009687:Nuclear Proteins / Q000737:chemistry*; D010879:Piperazines / Q000494:pharmacology*; D054198:Precursor Cell Lymphoblastic Leukemia-Lymphoma / Q000188:drug therapy* / Q000378:metabolism; D011743:Pyrimidines / Q000494:pharmacology*
chemical_list: D048868:Adaptor Proteins, Signal Transducing; D000970:Antineoplastic Agents; D001549:Benzamides; C082869:CRKL protein; D009687:Nuclear Proteins; D010879:Piperazines; D011743:Pyrimidines; D000068877:Imatinib Mesylate; D016044:Fusion Proteins, bcr-abl; C498826:nilotinib