title: Potential value of rapid prostate-specific antigen decline in identifying primary resistance to abiraterone acetate and enzalutamide.
abstract: OBJECTIVE
  To identify factors predicting primary resistance to new-generation hormonal agents (NHAs), abiraterone acetate and enzalutamide in patients with castration-resistant prostate cancer (CRPC).
  
  
  METHODS
  Our hospital has conducted two successive named patient NHA programs. A total of 57 patients with progressive CRPC previously treated with first-line docetaxel-based chemotherapy received standard NHA doses: abiraterone acetate 1000 mg once-daily combined with prednisone (5 mg twice daily) or enzalutamide 160 mg once-daily. Patients, who were assessed monthly to check their hematological parameters and prostate-specific antigen (PSA) levels, also underwent imaging investigations every 3-4 months. In total, 24 variables were assessed as potential predictors of primary NHA resistance.
  
  
  RESULTS
  Univariate analysis indicated that baseline pain and lactate dehydrogenase levels, and PSA levels after 1 month's treatment were predictive of primary NHA resistance. Only the predictive value of PSA levels after 1 month of treatment was confirmed at multivariate analysis. This factor strongly predicted progression-free and overall survival.
  
  
  CONCLUSIONS
  RESULTS suggest the use of a simple and rapid method of identifying patients with primary resistance to NHAs: patients not achieving a ≥ 50% reduction in PSA levels within the first treatment month should undergo intensive investigations to verify whether they have primary resistance to NHAs.
authors.affiliation: Medical Oncology Department, Santa Chiara Hospital, Trento, Italy.
authors.forename: Orazio
authors.initials: O
authors.lastname: Caffo
authors.forename: Antonello
authors.initials: A
authors.lastname: Veccia
authors.forename: Francesca
authors.initials: F
authors.lastname: Maines
authors.forename: Alberto
authors.initials: A
authors.lastname: Bonetta
authors.forename: Gilbert
authors.initials: G
authors.lastname: Spizzo
authors.forename: Enzo
authors.initials: E
authors.lastname: Galligioni
mesh_terms: D000069501:Abiraterone Acetate; D000368:Aged; D000369:Aged, 80 and over; D000730:Androstadienes / Q000627:therapeutic use*; D000971:Antineoplastic Combined Chemotherapy Protocols; D001549:Benzamides; D018450:Disease Progression; D019008:Drug Resistance, Neoplasm; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D008875:Middle Aged; D009570:Nitriles; D010669:Phenylthiohydantoin / Q000031:analogs & derivatives* / Q000627:therapeutic use; D011379:Prognosis; D017430:Prostate-Specific Antigen / Q000378:metabolism*; D011471:Prostatic Neoplasms / Q000188:drug therapy* / Q000378:metabolism* / Q000401:mortality; D016896:Treatment Outcome
chemical_list: D000730:Androstadienes; D001549:Benzamides; D009570:Nitriles; D010669:Phenylthiohydantoin; C540278:enzalutamide; D017430:Prostate-Specific Antigen; D000069501:Abiraterone Acetate
keywords: abiraterone acetate; castration-resistant prostate cancer; enzalutamide; predictive factors