Dose study of the multikinase inhibitor, LY2457546, in patients with relapsed acute myeloid leukemia to assess safety, pharmacokinetics, and pharmacodynamics

Abstract

Volker Wacheck1, Michael Lahn2, Gemma Dickinson3, Wolfgang Füreder4, Renata Meyer4, Susanne Herndlhofer4, Thorsten Füreder1, Georg Dorfner5, Sada Pillay2, Valérie André6, Timothy P Burkholder7, Jacqueline K Akunda8, Leann Flye-Blakemore9, Dirk Van Bockstaele9, Richard F Schlenk10, Wolfgang R Sperr4, Peter Valent4,111Department of Clinical Pharmacology, Medical University of Vienna, Währinger Gürtel, Vienna, Austria; 2Early Oncology Clinical Investigation, Eli Lilly and Company, Indianapolis, IN, USA; 3Department of Pharmacokinetics, Eli Lilly and Company, Erl Wood Research Centre, Windlesham, Surrey, UK; 4Department of Internal Medicine I, Division of Hematology and Hemostaseology, Medical University of Vienna, Währinger Gürtel, Vienna, Austria; 5Eli Lilly GesmbH, Medical Department, Vienna, Austria; 6Department of Statistics, Eli Lilly and Company, Erl Wood Research Centre, Surrey, UK; 7Discovery Chemistry Research and Technology, Eli Lilly and Company, Indianapolis, IN, USA; 8Nonclinical Toxicology, Eli Lilly and Company, Indianapolis, IN, USA; 9Flow Cytometry and Cell Analysis, Esoterix Clinical Trials Services, Mechelen, Belgium; 10Universitätsklinikum Ulm, Klinik für Innere Medizin III, Ulm, Germany; 11Ludwig Boltzmann Cluster Oncology, Vienna, AustriaBackground: Acute myeloid leukemia (AML) is a life-threatening malignancy with limited treatment options in chemotherapy-refractory patients. A first-in-human dose study was designed to investigate a safe and biologically effective dose range for LY2457546, a novel multikinase inhibitor, in patients with relapsed AML.Methods: In this nonrandomized, open-label, dose escalation Phase I study, LY2457546 was administered orally once a day. Safety, pharmacokinetics, changes in phosphorylation of target kinases in AML blasts, and risk of drug–drug interactions (DDI) were assessed.Results: Five patients were treated at the starting and predicted minimal biologically effective dose of 50 mg/day. The most commonly observed adverse events were febrile neutropenia, epistaxis, petechiae, and headache. The majority of adverse events (81%) were Grade 1 or 2. One patient had generalized muscle weakness (Grade 3), which was deemed to be a dose-limiting toxicity. Notably, the pharmacokinetic profile of LY2457546 showed virtually no elimination of LY2457546 within 24 hours, and thus prevented further dose escalation. No significant DDI were observed. Ex vivo flow cytometry studies showed downregulation of the phosphoproteins, pcKIT, pFLT3, and pS6, in AML blasts after LY2457546 administration. No medically relevant responses were observed in the five treated patients.Conclusion: No biologically effective dose could be established for LY2457546 in chemotherapy-resistant AML patients. Lack of drug clearance prevented safe dose escalation, and the study was terminated early. Future efforts should be made to develop derivatives with a more favorable pharmacokinetic profile.Keywords: multikinase inhibitor, pharmacokinetics, safety, acute myeloid leukemia, pharmacodynamics