title: Expression of AR-V7 in Circulating Tumour Cells Does Not Preclude Response to Next Generation Androgen Deprivation Therapy in Patients with Castration Resistant Prostate Cancer.
abstract: The androgen receptor splice variant AR-V7 has recently been discussed as a predictive biomarker for nonresponse to next-generation androgen deprivation therapy (ADT) in patients with castration-resistant prostate cancer. However, we recently identified one patient showing a response from abiraterone despite expression of AR-V7 in his circulating tumour cells (CTC). Therefore, we precisely assessed the response in a cohort of 21 AR-V7 positive castration-resistant prostate cancer patients who had received therapy with abiraterone or enzalutamide. We detected a subgroup of six AR-V7 positive patients showing benefit from either abiraterone or enzalutamide. Their progression free survival was 26 d (censored) to 188 d. Four patients displayed a prostate-specific antigen decrease of >50%. When analysing prior therapies, we noticed that only one of the six patients had received next-generation ADT prior to CTC collection. As a result, we conclude that AR-V7 status in CTC cannot entirely predict nonresponse to next generation ADT and AR-V7-positive patients should not be systematically denied abiraterone or enzalutamide treatment, especially as effective alternative treatment options are still limited.
  
  
  
  A subgroup of patients can benefit from abiraterone and/or enzalutamide despite detection of AR-V7 splice variants in their circulating tumour cells.
authors.affiliation: Clinic of Urology, University Hospital Muenster, Muenster, Germany.
authors.forename: Christof
authors.initials: C
authors.lastname: Bernemann
authors.affiliation: Clinic of Urology, University Hospital Ulm, Ulm, Germany.
authors.forename: Thomas J
authors.initials: TJ
authors.lastname: Schnoeller
authors.affiliation: Clinic of Urology, University Hospital Ulm, Ulm, Germany.
authors.forename: Manuel
authors.initials: M
authors.lastname: Luedeke
authors.affiliation: Gerhard-Domagk-Institute of Pathology, University Hospital Muenster, Muenster, Germany.
authors.forename: Konrad
authors.initials: K
authors.lastname: Steinestel
authors.affiliation: Clinic of Urology, University Hospital Muenster, Muenster, Germany.
authors.forename: Martin
authors.initials: M
authors.lastname: Boegemann
authors.affiliation: Clinic of Urology, University Hospital Muenster, Muenster, Germany.
authors.forename: Andres J
authors.initials: AJ
authors.lastname: Schrader
authors.affiliation: Clinic of Urology, University Hospital Muenster, Muenster, Germany. Electronic address: julie.steinestel@ukmuenster.de.
authors.forename: Julie
authors.initials: J
authors.lastname: Steinestel
mesh_terms: D059002:Androgen Receptor Antagonists / Q000627:therapeutic use*; D000736:Androstenes / Q000627:therapeutic use; D001549:Benzamides; D019008:Drug Resistance, Neoplasm / Q000235:genetics / Q000502:physiology; D006801:Humans; D008297:Male; D009360:Neoplastic Cells, Circulating / Q000187:drug effects / Q000378:metabolism*; D009570:Nitriles; D010669:Phenylthiohydantoin / Q000031:analogs & derivatives / Q000627:therapeutic use; D064129:Prostatic Neoplasms, Castration-Resistant / Q000188:drug therapy* / Q000378:metabolism* / Q000628:therapy; D020033:Protein Isoforms / Q000096:biosynthesis; D011944:Receptors, Androgen / Q000096:biosynthesis* / Q000378:metabolism; D012189:Retrospective Studies
chemical_list: C410798:AR protein, human; D059002:Androgen Receptor Antagonists; D000736:Androstenes; D001549:Benzamides; D009570:Nitriles; D020033:Protein Isoforms; D011944:Receptors, Androgen; D010669:Phenylthiohydantoin; C540278:enzalutamide; C089740:abiraterone
keywords: AR-V7; Abiraterone; Androgen receptor splice variant; Castration resistant prostate cancer; Enzalutamide