FDA Approved drug,Jan 2012 Ivacaftor
Generic name: Ivacaftor Trade name: Kalydeco Code designation: VX-770 IUPAC Name : N-(2,4-di-tert-butyl-5-hydroxyphenyl)-4-oxo-1,4dihydroquinoline-3-carboxamideDate of approval : January 31, 2012
Innovative company: Ivacaftor has been developed by Vertex Pharmaceuticals (which it is also marketed by), and the Cystic Fibrosis Foundation.
ATC code R07AX02 CAS number: 873054-44-5 PubChemCID : 16220172 ChemSpider: 17347474 UNII: 1Y740ILL1Z SMILES : O=C\2c1c(cccc1)N/C=C/2C(=O)Nc3cc(O)c(cc3C(C)(C)C)C(C)(C)C InChI: 1S/C24H28N2O3/c1-23(2,3)16-11-17(24(4,5)6)20(27)12-19(16)2622(29)15-13-25-18-10-8-7-9-14(18)21(15)28/h7-13,27H,16H3,(H,25,28)(H,26,29)
Dosage form: oral tablets 150mg
Indication: For the treatment of cystic fibrosis (CF) in patients age 6 years and older who have a G551D mutation in the CFTR gene.
Mechanism of Action Ivacaftor is a potentiator of the CFTR protein. The CFTR protein is a chloride channel present at the surface of epithelial cells in multiple organs. Ivacaftor facilitates increased chloride transport by potentiating the channel-open probability (or gating) of the G551D-CFTR protein.
Cystic FibrosisCystic fibrosis is an autosomal genetic disease affecting most critically the lungs, and also the pancreas, liver, and intestine. It is characterized by abnormal transport of chloride and sodium across epithelium, leading to thick, viscous secretions. CF is caused by a mutation in the gene for the protein cystic fibrosis transmembrane conductance regulator (CFTR). This gene is required to regulate the components of sweat, digestive juices, and mucus.
Location : in epithelial cells of lungs, pancreas, liver, sweat glands, digestive tract and reproductive system.
Transmembrane glycoprotein ABC family (ATP Binding Cassette) 1480 amino acids 170 kDa 5 domains 2 transmembrane domains (TM1, TM2), 6 alpha helixes, chloride channel 2 nucleotid binding domains (NBD1, NBD2), cytoplasmic, ATP fixation and hydrolysis 1 regulatory domain (RD) : phosphorylation by PKA, AMPc dependant.
Rescue of deltaF508-CFTR trafficking and gating in human cystic fibrosis airway cultures by small molecules Chloride channels as drug targets Alan S. Verkman* and Luis J. V. Galietta
Molecular structure of the CFTR proteinhttp://upload.wikimedia.org/wikipedia/commons/0/09/CFTR.jpg
1480 amino acids
NBD1 of human CFTR complexed with ATP.http://upload.wikimedia.org/wikipedia/commons/0/03/Protein_CFTR_PDB_1xmi.png
Activation of CFTR
Activation of CFTR PKA-regulated AMPc dependant phosphorylation of the RD NBD1 : ATP hydrolysis open NBD2 : ATP hydrolysis close
Passage of chloride ions and bicarbonate through the plasma membrane.Biochimie mdicale Marqueurs actuels et perspectives 2e dition Jean-Louis Beaudeux Genevive Durand Medecine Sciences Publications Lavoisier
Role of the CFTR channel Nature : transmembrane glycoprotein from ATP- binding cassette family. Function : Epithelial anion channel involved in chloride transport. Maintenance of exocrine Inhibition of the sodium reabsorption by the channel ENac Non-water reabsorption
Interface inserm/SFP Nouvelles thrapies dans la muciviscidose en 2011. I.Sermet-Gaudelus, M. Le Bourgeois, J. de Blc, G.Lenoir, A. Edelman Vertex Pharmaceuticals
Consequence of loss of function Interferences with CFTR folding, trafficking, membrane stability, and channel gating. Absent or defective CFTR causes abnormal ion transport.
Regulatory domain phosphorylation to distinguish the mechanistic basis underlying acute CFTR modulator Am J Physiol Lung Cell Mol Physiol 301:L587-L597, 2011. First published 1 July 2011
Most frequent defects associated with CFDifferent classes of mutation:Classe I: Defective protein production Classe II: Defective protein processing F508
Classe III: Defective protein regulation G511DClasse IV: Defective channel conductance Classe V: Reduce synthesisPharmacological therapy for cystic fibrosis: From bench to bedside Frdric Becqa,*, Marcus A. Mallb, David N. Sheppardc, Massimo Conesed,e, Olga Zegarra-Moranf
Location of the amino acid alterations associatedwith CFTR gatingmutations tested in this study.
Most frequent defects F508-CFTR Reduced CFTR density and activity in the apical membrane Impaired epithelial cell function Deletion of Phe (codon 508) 90% of CF patients 50% homozygous for the F508CFTR F508-CFTR, which occurs in >90% of patients in the U.S., creates a protein that does not fold normally and is degraded by the cell.
Rescue of deltaF508-CFTR trafficking and gating in human cystic fibrosis airway cultures by small molecules and Gene Mutations in Cystic Fibrosis, Vertex.
Most frequent defects G551D-CFTR Dysfunctional CFTR Mutation codon 551(Gly Asp)
Impaired epithelial cell function
France: 6.000 patients F508del / G551D : 53; 0,9%
Registre Francais de la Mucoviscdose : rapport de donnes 2009 and Gene Mutations in Cystic Fibrosis, Vertex The Cystic Fibrosis Mutation G551D Alters the Non-Michaelis Menten Behavior of the Cystic Fibrosis Transmembrane Conductance Regulator (CFTR) Channel and Abolishes the Inhibitory Genistein Binding Site
Pharmacokinetics:Absorption The exposure of ivacaftor increased approximately 2- to 4-fold when given with food containing fat. The median (range) tmax is approximately 4.0 (3.0; 6.0) hours in the fed state.
Distribution Ivacaftor is approximately 99% bound to plasma proteins, primarily to alpha 1-acid glycoprotein and albumin. Ivacaftor does not bind to human red blood cells.
Pharmacokinetics:Metabolism Ivacaftor is extensively metabolized in humans ivacaftor is primarily metabolized by CYP3A. M1 and M6 are the two major metabolites of ivacaftor in humans. M1 has approximately one-sixth the potency of ivacaftor and is considered pharmacologically active. M6 has less than one-fiftieth the potency of ivacaftor and is not considered pharmacologically active. Elimination Following oral administration, the majority of ivacaftor (87.8%) is eliminated in the feces after metabolic conversion.
Dose:Adults and pediatric patients age 6 years and older: one 150 mg tablet taken orally every 12 hours with fatcontaining food. Reduce dose in patients with moderate and severe hepatic impairment. Reduce dose when co-administered with drugs that are moderate or strong CYP3A inhibitors.
ADVERSE REACTIONS: The most common adverse drug reactions to KALYDECO were headache, oropharyngeal pain, upper respiratory tract infection, nasal congestion, abdominal pain, nasopharyngitis, diarrhea, rash, nausea, and dizziness.