title: Development of HPLC and LC-MS/MS methods for the analysis of ivacaftor, its major metabolites and lumacaftor in plasma and sputum of cystic fibrosis patients treated with ORKAMBI or KALYDECO.
abstract: ORKAMBI (ivacaftor-lumacaftor [LUMA]) and KALYDECO (ivacaftor; IVA) are two new breakthrough cystic fibrosis (CF) drugs that directly modulate the activity and trafficking of the defective CFTR underlying the CF disease state. Currently, no therapeutic drug monitoring assays exist for these very expensive, albeit, important drugs. In this study, for the first time HPLC and LC-MS methods were developed and validated for rapid detection and quantification of IVA and its major metabolites hydroxymethyl-IVA M1 (active) and IVA-carboxylate M6 (inactive); and LUMA in the plasma and sputum of CF patients. With a mobile phase consisting of acetonitrile/water:0.1% formic acid (60:40v/v) at a flow rate of 1mL/min, a linear correlation was observed over a concentration range from 0.01 to 10μg/mL in human plasma (IVA R2>0.999, IVA M1 R2>0.9961, IVA M6 R2>0.9898, LUMA R2>0.9954). The assay was successfully utilized to quantify the concentration of LUMA, IVA, M1 and M6 in the plasma and sputum of CF patients undergoing therapy with KALYDECO (IVA 150mg/q12h) or ORKAMBI (200mg/q12h LUMA-125mg/q12h IVA). The KALYDECO patient exhibited an IVA plasma concentration of 0.97μg/mL at 2.5h post dosage. M1 and M6 plasma concentrations were 0.50μg/mL and 0.16μg/mL, respectively. Surprisingly, the ORKAMBI patient displayed very low plasma concentrations of IVA (0.06μg/mL) and M1 (0.07μg/mL). The M6 concentrations (0.15μg/mL) were comparable to those of the KALYDECO patient. However, we observed a relatively high plasma concentration of LUMA (4.42μg/mL). This reliable and novel method offers a simple and sensitive approach for therapeutic drug monitoring of KALYDECO and ORKAMBI in plasma and sputum. The introduction of the assay into the clinical setting will facilitate pharmacokinetics/pharmacodynamic analysis and assist clinicians to develop more cost effective and efficacious dosage regimens for these breakthrough CF drugs.
authors: Drug Delivery, Disposition and Dynamics, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, Victoria 3052, Australia.
authors: Elena K
authors: EK
authors: Schneider
authors: Drug Delivery, Disposition and Dynamics, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, Victoria 3052, Australia.
authors: Felisa
authors: F
authors: Reyes-Ortega
authors: Department of Medicine, Monash University, Alfred Hospital, Commercial Road, Melbourne, Victoria 3004, Australia; Department of Allergy, Immunology and Respiratory Medicine, Alfred Hospital, Commercial Road, Melbourne, Victoria 3004, Australia.
authors: John W
authors: JW
authors: Wilson
authors: Department of Medicine, Monash University, Alfred Hospital, Commercial Road, Melbourne, Victoria 3004, Australia; Department of Allergy, Immunology and Respiratory Medicine, Alfred Hospital, Commercial Road, Melbourne, Victoria 3004, Australia.
authors: Tom
authors: T
authors: Kotsimbos
authors: Department of Medicine, Monash University, Alfred Hospital, Commercial Road, Melbourne, Victoria 3004, Australia; Department of Allergy, Immunology and Respiratory Medicine, Alfred Hospital, Commercial Road, Melbourne, Victoria 3004, Australia.
authors: Dominic
authors: D
authors: Keating
authors: Drug Delivery, Disposition and Dynamics, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, Victoria 3052, Australia; Monash Biomedicine Discovery Institute, Department of Microbiology, Monash University, Clayton, Victoria 3800, Australia.
authors: Jian
authors: J
authors: Li
authors: Drug Delivery, Disposition and Dynamics, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, Victoria 3052, Australia. Electronic address: tony.velkov@monash.edu.
authors: Tony
authors: T
authors: Velkov
mesh_terms: D000627:Aminophenols / Q000097:blood* / Q000378:metabolism; D000631:Aminopyridines / Q000097:blood*; D052117:Benzodioxoles / Q000097:blood*; D002851:Chromatography, High Pressure Liquid / Q000191:economics / Q000379:methods*; D003550:Cystic Fibrosis / Q000188:drug therapy; D006801:Humans; D057230:Limit of Detection; D015363:Quinolones / Q000097:blood* / Q000378:metabolism; D013183:Sputum / Q000737:chemistry*; D053719:Tandem Mass Spectrometry / Q000191:economics / Q000379:methods*
chemical_list: D000627:Aminophenols; D000631:Aminopyridines; D052117:Benzodioxoles; D015363:Quinolones; C545203:ivacaftor; C569105:lumacaftor
keywords: Cystic fibrosis; Ivacaftor; LC/MS; Lumacaftor; Plasma; Sputum