Kategorie: Maligní lymfomy a leukémie
Téma: Chronic myeloid leukemia - Biology
Číslo abstraktu: P708
Autoři: MD Dominik Wolf; Jörn Skavland, Ph.D.; Priv. Doz. Dr. rer. nat. Christoph Seger, Ph.D.; Sieghart Sopper, Ph.D.; Prof. Dr. Wieslaw Wiktor-Jedrzejczak, PhD; Dubravka Sertic; MUDr. Jaroslava Voglová; MD Satu Mustjoki, PhD; MD Leif Stenke, PhD; Prof. Augustin Ferrant; MD Richard Greil, Ph.D.; Dr. Alois Lang; Dr. Josef Thaler, Ph.D.; Univ.-Prof. Dr.med.univ. Werner Linkesch; MD Antica Duletić-Načinović, PhD; MD Andrzej Hellmann, Ph.D.; Prof. M.D. Georgi Mihaylov, Ph.D.; MD Tobias Gedde-Dahl, PhD; M.D. Henrik Hjort-Hansen, Ph.D.; Mohammed Majeed; MD Jesper Stentoft, PhD; Prof. Dr. Gregor Verhoef, Ph.D.; MD Jan van Droogenbroeck, PhD; Ute Mark; Dr. Jens Haenig; Nidas Jurjonas; Prof. MD Thomas Lion, PhD; MD Günther Gastl; Prof. MD Frank Giles, M.B.; MD Andreas Hochhaus; MD Kimmo Porkka, PhD; MD Gert (J.) Ossenkoppele, PhD; Prof. MD Bjoern-Tore Gjertsen, PhD
Imatinib trough plasma level testing and pharmacodynamic evaluation (i.e. quantification of phosphorylated CrkL) may help to tailor patient-specific therapy.For the 2nd generation TKI nilotinib the value of such information is less clear.
We here present first data from a substudy of the phase IV ENEST1st trial testing uP-front nilotinib therapy in early chronic phase CML. The study addressed the value of plasma-level testing and protein phosphorylation pharmacodynamics for clinical outcome.
Drug levels were centrally quantified by means of mass spectrometry (HPLC-MS/MS) in 54 patients at 3 hours after first drug intake at day (d) 1 (Cmax) and at d7, d28 and months (m)3,6, 12 prior to morning drug intake (Cmin). Single cell quantification of intracellular protein phosphorylation was performed by flow cytometry (phosphoflow) in the myelocyte cell population after full blood fixation/cell permeabilization/erythrocyte lysis. BCR-ABL phosphoprotein signalling was detected by phosphoflow at d1 prior to first drug intake, 3 hours after first drug intake as well as at d7 and d28.
In our first analysis we focussed on correlation with early molecular response, i.e. IS 0.1% (MMR) and CMR at months3,6, and 12. Of the 54 patients, 21% achieved MMR at 3m and 55% at 6m of therapy (including 2 CMR). Only 4 patients at 3m and 1 patient at 6m did show less than IS 10% BCR-ABL load. 11% achieved CMR at 12m with remaining patients except one showing MMR. At d1 three hours after first drug intake median peak plasma levels reached 405 (range 0-1188) ng/mL increasing to a median trough level of 820 ng/mL at d7 and 880 ng/mL at d28. Thereafter from d28 to d360 plasma trough levels remained stable with individual values ranging from 347 to 2522 ng/mL. Initial Cmax-levels at d1 significantly correlated with steady state levels thereafter. In addition, the final steady state levels were also influenced by the slope of the subsequent increase (ranging from -21% to 580%). Higher plasma levels of nilotinib were significantly associated with lower BCR-ABL mRNA burden at 3m with a similar trend observed at 6m and 12m. If median steady-state drug levels were compared in different response categories (CMR vs. no CMR, MMR vs. no MMR, >IS 10% at 3m vs. <IS 10%) we could identify significantly higher levels in MMR at 3m (P=0.0083), as well as increased 3m plasma levels were associated with MMR at 6m (P=0.045) and CMR at 12m (P=0.001). Phosphoflow of myelocytes revealed that compared to baseline, phosphorylation of almost all investigated proteins decreases over time, including significant reduction of phospho-Gab2(Y452), Abl(Y245), STAT5(Y694), Erk1/2(T202/Y204), p38(T108/Y182) at d28. Correlation of plasma levels with changes in phosphorylation status revealed a negative correlation of increasing drug levels with decreasing phospho-p38 and phospho-STAT5 status.
Summary and Conclusions:
Interindividual plasma levels show a relatively wide variability. Cmax levels upon first drug exposure correlate with later trough levels pointing out to a potential individual pharmacogenetic background regulating systemic drug availability. Higher trough nilotinib plasma levels are associated with improved response rates. Single cell myelocyte phosphoprotein detection allowed direct monitoring of components in the BCR-ABL signalling network. More detailed analyses will be presented at the meeting.
Datum přednesení příspěvku: 15. 6. 2013