|References on PF-04217903:
1 . Drug Metab Dispos. 2011 Mar;39(3):383-93. Epub 2010 Nov 23.
The objective of this study was to assess the physiologically based pharmacokinetic (PBPK) model for predicting plasma concentration-time profiles of orally available cMet kinase inhibitors, (R)-3-[1-(2,6-dichloro-3-fluoro-phenyl)-ethoxy]-5-(1-piperidin-4-yl-1H-pyrazol-4-yl)-pyridin-2-ylamine (PF02341066) and 2-[4-(3-quinolin-6-ylmethyl-3H-[1,2,3]triazolo[4,5-b]pyrazin-5-yl)-pyrazol-1-yl]-ethanol (PF04217903), in humans. The prediction accuracy of pharmacokinetics (PK) by PBPK modeling was compared with that of a traditional one-compartment PK model based on allometric scaling. The predicted clearance values from allometric scaling with the correction for the interspecies differences in protein binding were used as a representative comparison, which showed more accurate PK prediction in humans than the other methods. Overall PBPK modeling provided better prediction of the area under the plasma concentration-time curves for both PF02341066 (1.2-fold error) and PF04217903 (1.3-fold error) compared with the one-compartment PK model (1.8- and 1.9-fold errors, respectively). Of more importance, the simulated plasma concentration-time profiles of PF02341066 and PF04217903 by PBPK modeling seemed to be consistent with the observed profiles showing multiexponential declines, resulting in more accurate prediction of the apparent half-lives (t(1/2)): the observed and predicted t(1/2) values were, respectively, 10 and 12 h for PF02341066 and 6.6 and 6.3 h for PF04217903. The predicted t(1/2) values by the one-compartment PK model were 17 h for PF02341066 and 1.9 h for PF04217903. Therefore, PBPK modeling has the potential to be more useful and reliable for the PK prediction of PF02341066 and PF04217903 in humans than the traditional one-compartment PK model. In summary, the present study has shown examples to indicate that the PBPK model can be used to predict PK profiles in humans.
2 . Lee NV, Lira ME, Pavlicek A, Ye J, Buckman D, Bagrodia S, Srinivasa SP, Zhao Y, Aparicio S, Rejto PA, Christensen JG, Ching KA.A novel SND1-BRAF fusion confers resistance to c-Met inhibitor PF-04217903 in GTL16 cells though MAPK activation.PLoS One. 2012;7(6):e39653. Epub 2012 Jun 22.
Targeting cancers with amplified or abnormally activated c-Met (hepatocyte growth factor receptor) may have therapeutic benefit based on nonclinical and emerging clinical findings. However, the eventual emergence of drug resistant tumors motivates the pre-emptive identification of potential mechanisms of clinical resistance. We rendered a MET amplified gastric cancer cell line, GTL16, resistant to c-Met inhibition with prolonged exposure to a c-Met inhibitor, PF-04217903 (METi). Characterization of surviving cells identified an amplified chromosomal rearrangement between 7q32 and 7q34 which overexpresses a constitutively active SND1-BRAF fusion protein. In the resistant clones, hyperactivation of the downstream MAPK pathway via SND1-BRAF conferred resistance to c-Met receptor tyrosine kinase inhibition. Combination treatment with METi and a RAF inhibitor, PF-04880594 (RAFi) inhibited ERK activation and circumvented resistance to either single agent. Alternatively, treatment with a MEK inhibitor, PD-0325901 (MEKi) alone effectively blocked ERK phosphorylation and inhibited cell growth. Our results suggest that combination of a c-Met tyrosine kinase inhibitor with a BRAF or a MEK inhibitor may be effective in treating resistant tumors that use activated BRAF to escape suppression of c-Met signaling.
3 . Cui JJ, McTigue M, Nambu M, Tran-Dubé M, Pairish M, Shen H, Jia L, Cheng H, Hoffman J, Le P, Jalaie M, Goetz GH, Ryan K, Grodsky N, Deng YL, Parker M, Timofeevski S, Murray BW, Yamazaki S, Aguirre S, Li Q, Zou H, Christensen J.Discovery of a Novel Class of Exquisitely Selective Mesenchymal-Epithelial Transition Factor (c-MET) Protein Kinase Inhibitors and Identification of the Clinical Candidate 2-(4-(1-(Quinolin-6-ylmethyl)-1H-[1,2,3]triazolo[4,5-b]pyrazin-6-yl)-1H-pyrazol-1-yl)ethanol (PF-04217903) for the Treatment of Cancer.J Med Chem. 2012 Sep 10.
The c-MET receptor tyrosine kinase is an attractive oncology target because of its critical role in human oncogenesis and tumor progression. An oxindole hydrazide hit 6 was identified during a c-MET HTS campaign and subsequently demonstrated to have an unusual degree of selectivity against a broad array of other kinases. The cocrystal structure of the related oxindole hydrazide c-MET inhibitor 10 with a nonphosphorylated c-MET kinase domain revealed a unique binding mode associated with the exquisite selectivity profile. The chemically labile oxindole hydrazide scaffold was replaced with a chemically and metabolically stable triazolopyrazine scaffold using structure based drug design. Medicinal chemistry lead optimization produced 2-(4-(1-(quinolin-6-ylmethyl)-1H-[1,2,3]triazolo[4,5-b]pyrazin-6-yl)-1H-pyrazol-1-yl)ethanol (2, PF-04217903), an extremely potent and exquisitely selective c-MET inhibitor. 2 demonstrated effective tumor growth inhibition in c-MET dependent tumor models with good oral PK properties and an acceptable safety profile in preclinical studies. 2 progressed to clinical evaluation in a Phase I oncology setting.
4 . Lee NV, Lira ME, Pavlicek A, Ye J, Buckman D, Bagrodia S, Srinivasa SP, Zhao Y, Aparicio S, Rejto PA, Christensen JG, Ching KA.Correction: A Novel SND1-BRAF Fusion Confers Resistance to c-Met Inhibitor PF-04217903 in GTL16 Cells though MAPK Activation.PLoS One. 2012;7(8).
[This corrects the article on p. e39653 in vol. 7.].
5 . Sergei L. Timofeevski et al. Enzymatic Characterization of c-Met Receptor Tyrosine Kinase Oncogenic Mutants and Kinetic Studies with Aminopyridine and Triazolopyrazine Inhibitors Biochemistry, 2009, 48 (23), pp 5339-5349
The c-Met receptor tyrosine kinase (RTK) is a key regulator in cancer, in part, through oncogenic mutations. Eight clinically relevant mutants were characterized by biochemical, biophysical, and cellular methods. The c-Met catalytic domain was highly active in the unphosphorylated state (kcat = 1.0 s?1) and achieved 160-fold enhanced catalytic efficiency (kcat/Km) upon activation to 425000 s?1 M?1. c-Met mutants had 2?10-fold higher basal enzymatic activity (kcat) but achieved maximal activities similar to those of wild-type c-Met, except for Y1235D, which underwent a reduction in maximal activity. Small enhancements of basal activity were shown to have profound effects on the acquisition of full enzymatic activity achieved through accelerating rates of autophosphorylation. Biophysical analysis of c-Met mutants revealed minimal melting temperature differences indicating that the mutations did not alter protein stability. ...