title: Enzalutamide as a Fourth- or Fifth-Line Treatment Option for Metastatic Castration-Resistant Prostate Cancer.
abstract: OBJECTIVE
  To evaluate the efficacy of enzalutamide (Enz) as fourth- or fifth-line treatment in men with metastasized castration-resistant prostate cancer (mCRPC), by analyzing a retrospective cohort of heavily pretreated patients.
  
  
  METHODS
  We evaluated toxicity, overall survival (OS), progression-free survival (PFS) and time to prostate-specific antigen (PSA) progression data from 47 CRPC patients treated with fourth- or fifth-line Enz.
  
  
  RESULTS
  All patients were treated with docetaxel and abiraterone acetate and 42 patients (89%) with cabazitaxel. The median age of the patients was 69 years (IQR, 63-73.5), 79% had bone metastases, 55% had lymph node metastases, and 17% had visceral metastases. The median duration of Enz treatment was 12.0 weeks (IQR, 8.3-20.4), and 11 patients (23%) responded to Enz (maximum PSA decline ≥50%). In general, Enz was well tolerated, with the most frequently reported adverse events being fatigue and nausea. The median OS was 40.1 weeks (95% CI, 25.4-61.4), the median PFS was 12.1 weeks (95% CI, 9.9-14.0) and the median time to PSA progression was 15.7 weeks (95% CI, 14.0-28.7).
  
  
  CONCLUSIONS
  Analysis of this retrospective cohort suggests that Enz is well tolerated and that there is a 23% response rate in heavily pretreated CRPC patients, which is comparable with third-line treatment outcomes.
authors.affiliation: Department of Medical Oncology, Netherlands Cancer Institute, Amsterdam, The Netherlands.
authors.forename: Sushil K
authors.initials: SK
authors.lastname: Badrising
authors.forename: Vincent
authors.initials: V
authors.lastname: van der Noort
authors.forename: Paul
authors.initials: P
authors.lastname: Hamberg
authors.forename: Jules L L M
authors.initials: JL
authors.lastname: Coenen
authors.forename: Maureen J
authors.initials: MJ
authors.lastname: Aarts
authors.forename: Inge M
authors.initials: IM
authors.lastname: van Oort
authors.forename: Alfons J M
authors.initials: AJ
authors.lastname: van den Eertwegh
authors.forename: Maartje
authors.initials: M
authors.lastname: Los
authors.forename: H Pieter
authors.initials: HP
authors.lastname: van den Berg
authors.forename: Hans
authors.initials: H
authors.lastname: Gelderblom
authors.forename: Suzan
authors.initials: S
authors.lastname: Vrijaldenhoven
authors.forename: Emile D
authors.initials: ED
authors.lastname: Kerver
authors.forename: Theo
authors.initials: T
authors.lastname: van Voorthuizen
authors.forename: Igle J
authors.initials: IJ
authors.lastname: de Jong
authors.forename: John B
authors.initials: JB
authors.lastname: Haanen
authors.forename: Andries M
authors.initials: AM
authors.lastname: Bergman
mesh_terms: D000008:Abdominal Neoplasms / Q000188:drug therapy* / Q000556:secondary; D000069501:Abiraterone Acetate / Q000627:therapeutic use; D000368:Aged; D000970:Antineoplastic Agents / Q000009:adverse effects / Q000627:therapeutic use*; D001549:Benzamides; D001859:Bone Neoplasms / Q000188:drug therapy* / Q000556:secondary; D018450:Disease Progression; D018572:Disease-Free Survival; D000077143:Docetaxel; D006801:Humans; D008207:Lymphatic Metastasis; D008297:Male; D008875:Middle Aged; D009570:Nitriles; D010669:Phenylthiohydantoin / Q000009:adverse effects / Q000031:analogs & derivatives* / Q000627:therapeutic use; D064129:Prostatic Neoplasms, Castration-Resistant / Q000188:drug therapy* / Q000473:pathology*; D011868:Radioisotopes / Q000627:therapeutic use; D011883:Radium / Q000627:therapeutic use; D019233:Retreatment; D012189:Retrospective Studies; D015996:Survival Rate; D043823:Taxoids / Q000627:therapeutic use
chemical_list: D000970:Antineoplastic Agents; D001549:Benzamides; D009570:Nitriles; D011868:Radioisotopes; D043823:Taxoids; D000077143:Docetaxel; D010669:Phenylthiohydantoin; C552428:cabazitaxel; C540278:enzalutamide; D000069501:Abiraterone Acetate; D011883:Radium