Abstract
Crizotinib [Xalkori; PF02341066; (R)-3-[1-(2,6-dichloro-3-fluoro-phenyl)-ethoxy]-5-(1-piperidin-4-yl-1H-pyrazol-4-yl)-pyridin-2-ylamine] is an orally available dual inhibitor of anaplastic lymphoma kinase (ALK) and hepatocyte growth factor receptor. The objectives of the present studies were to characterize: 1) the pharmacokinetic/pharmacodynamic relationship of crizotinib plasma concentrations to the inhibition of ALK phosphorylation in tumors, and 2) the relationship of ALK inhibition to antitumor efficacy in human tumor xenograft models. Crizotinib was orally administered to athymic nu/nu mice implanted with H3122 non–small-cell lung carcinomas or severe combined immunodeficient/beige mice implanted with Karpas299 anaplastic large-cell lymphomas. Plasma concentration-time courses of crizotinib were adequately described by a one-compartment pharmacokinetic model. A pharmacodynamic link model reasonably fit the time courses of ALK inhibition in both H3122 and Karpas299 models with EC50 values of 233 and 666 ng/ml, respectively. A tumor growth inhibition model also reasonably fit the time course of individual tumor growth curves with EC50 values of 255 and 875 ng/ml, respectively. Thus, the EC50 for ALK inhibition approximately corresponded to the EC50 for tumor growth inhibition in both xenograft models, suggesting that >50% ALK inhibition would be required for significant antitumor efficacy (>50%). Furthermore, based on the observed clinical pharmacokinetic data coupled with the pharmacodynamic parameters obtained from the present nonclinical xenograft mouse model, >70% ALK inhibition was projected in patients with non–small-cell lung cancer who were administered the clinically recommended dosage of crizotinib, twice-daily doses of 250 mg (500 mg/day). The result suggests that crizotinib could sufficiently inhibit ALK phosphorylation for significant antitumor efficacy in patients.
Footnotes
Article, publication date, and citation information can be found at http://jpet.aspetjournals.org.
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ABBREVIATIONS:
- EGFR
- epidermal growth factor receptor
- ALCL
- anaplastic large cell lymphoma
- ALK
- anaplastic lymphoma kinase
- Ce
- effect-site concentration of crizotinib
- CL/F
- oral clearance
- Cp
- plasma concentration of crizotinib
- crizotinib (PF02341066)
- (R)-3-[1-(2,6-dichloro-3-fluoro-phenyl)-ethoxy]-5-(1-piperidin-4-yl-1H-pyrazol-4-yl)-pyridin-2-ylamine
- E0
- ALK phosphorylation baseline
- Emax
- maximum effect
- EML4
- echinoderm microtubule-associated protein-like 4
- γ
- Hill coefficient
- ka
- absorption rate constant
- ke0
- rate constant for equilibration with the effect site
- ktd
- first-order tumor death rate constant
- ktg
- first-order tumor growth rate constant
- MET
- hepatocyte growth factor receptor
- NSCLC
- non–small-cell lung cancer
- OFV
- objective function value
- PK/PD
- pharmacokinetic/pharmacodynamic
- T
- tumor volume
- TGI
- tumor growth inhibition
- Tss
- maximum sustainable tumor volume
- Vd/F
- oral volume of distribution
- S1
- study 1
- S2
- study 2
- S3
- study 3.
- Received October 12, 2011.
- Accepted November 29, 2011.
- Copyright © 2012 by The American Society for Pharmacology and Experimental Therapeutics
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