title: Simultaneous quantitation of abiraterone, enzalutamide, N-desmethyl enzalutamide, and bicalutamide in human plasma by LC-MS/MS.
abstract: Inhibiting the androgen receptor (AR) pathway is an important clinical strategy in metastatic prostate cancer. Novel agents including abiraterone acetate and enzalutamide have been shown to prolong life in men with metastatic, castration-resistant prostate cancer (mCRPC). To evaluate the pharmacokinetics of AR-targeted agents, we developed and validated an LC-MS/MS assay for the quantitation of enzalutamide, N-desmethyl enzalutamide, abiraterone and bicalutamide in 0.05mL human plasma. After protein precipitation, chromatographic separation was achieved with a Phenomenex Synergi Polar-RP column and a linear gradient of 0.1% formic acid in methanol and water. Detection with an ABI 4000Q mass spectrometer utilized electrospray ionization in positive multiple reaction monitoring mode. The assay was linear over the ranges of 1-1000ng/mL for abiraterone and bicalutamide and 100-30,000ng/mL for N-desmethyl enzalutamide and enzalutamide and proved to be accurate (92.8-107.7%) and precise (largest was 15.3% CV at LLOQ for bicalutamide), and fulfilled FDA criteria for bioanalytical method validation. We demonstrated the suitability of this assay in plasma from patients who were administered enzalutamide 160mg, abiraterone 1000mg and bicalutamide 50mg once a day as monotherapy or in combination. The LC-MS/MS assay that has been developed will be an essential tool that further defines the pharmacology of the combinations of androgen synthesis or AR-receptor targeted agents.
authors.affiliation: Cancer Therapeutics Program, University of Pittsburgh Cancer Institute, Pittsburgh, PA, USA; Department of Oncology, Asan Medical Center, University of Ulsan College of Medicine, Seoul, South Korea; Division of Hematology-Oncology, Department of Medicine, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA.
authors.forename: Kyu-Pyo
authors.initials: KP
authors.lastname: Kim
authors.affiliation: Cancer Therapeutics Program, University of Pittsburgh Cancer Institute, Pittsburgh, PA, USA; Department of Pharmaceutical Sciences, School of Pharmacy, University of Pittsburgh, Pittsburgh, PA, USA.
authors.forename: Robert A
authors.initials: RA
authors.lastname: Parise
authors.affiliation: Cancer Therapeutics Program, University of Pittsburgh Cancer Institute, Pittsburgh, PA, USA.
authors.forename: Julianne L
authors.initials: JL
authors.lastname: Holleran
authors.affiliation: Norris Cotton Cancer Center, Dartmouth-Hitchcock Medical Center, The Geisel School of Medicine at Dartmouth, Hanover, NH, USA.
authors.forename: Lionel D
authors.initials: LD
authors.lastname: Lewis
authors.affiliation: Cancer Therapeutics Program, University of Pittsburgh Cancer Institute, Pittsburgh, PA, USA; Division of Hematology-Oncology, Department of Medicine, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA.
authors.forename: Leonard
authors.initials: L
authors.lastname: Appleman
authors.affiliation: Department of Clinical Pharmacy, Radboud University Nijmegen Medical Centre, Nijmegen, The Netherlands.
authors.forename: Nielka
authors.initials: N
authors.lastname: van Erp
authors.affiliation: Department of Medicine, Memorial Sloan Kettering Cancer Center, New York, NY, USA; Department of Medicine, Weill Medical College of Cornell University, New York, NY, USA.
authors.forename: Michael J
authors.initials: MJ
authors.lastname: Morris
authors.affiliation: Cancer Therapeutics Program, University of Pittsburgh Cancer Institute, Pittsburgh, PA, USA; Division of Hematology-Oncology, Department of Medicine, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA; Department of Pharmaceutical Sciences, School of Pharmacy, University of Pittsburgh, Pittsburgh, PA, USA. Electronic address: beumerj@gmail.com.
authors.forename: Jan H
authors.initials: JH
authors.lastname: Beumer
mesh_terms: D000736:Androstenes / Q000097:blood* / Q000737:chemistry* / Q000627:therapeutic use; D000813:Anilides / Q000097:blood* / Q000737:chemistry* / Q000627:therapeutic use; D001549:Benzamides; D002853:Chromatography, Liquid / Q000379:methods; D006801:Humans; D008297:Male; D009570:Nitriles / Q000097:blood* / Q000737:chemistry* / Q000627:therapeutic use; D010669:Phenylthiohydantoin / Q000031:analogs & derivatives* / Q000097:blood / Q000737:chemistry / Q000627:therapeutic use; D064129:Prostatic Neoplasms, Castration-Resistant / Q000097:blood / Q000188:drug therapy; D011944:Receptors, Androgen / Q000378:metabolism; D021241:Spectrometry, Mass, Electrospray Ionization / Q000379:methods; D014105:Tosyl Compounds / Q000097:blood* / Q000737:chemistry* / Q000627:therapeutic use
chemical_list: D000736:Androstenes; D000813:Anilides; D001549:Benzamides; D009570:Nitriles; D011944:Receptors, Androgen; D014105:Tosyl Compounds; D010669:Phenylthiohydantoin; C540278:enzalutamide; C053541:bicalutamide; C089740:abiraterone
keywords: Abiraterone; Assay; Bicalutamide; Enzalutamide; Metabolites; Tandem mass spectrometry; Validation