title: Effect of dutasteride in men receiving intermittent androgen ablation therapy: The AVIAS trial.
abstract: BACKGROUND
  We studied the effect of dutasteride on the length of the off-treatment period in prostate cancer patients on intermittent androgen deprivation (IAD) therapy.
  
  
  METHODS
  We conducted a randomized, placebo-controlled Phase II trial in men with localized prostate cancer and a rising prostate-specific antigen (PSA) level post-primary treatment. Patients were randomized to dutasteride (0.5 mg/day) or placebo. All patients received androgen deprivation therapy (ADT), which was stopped at month 9 if the PSA level was <1.0 ng/mL. ADT was resumed when PSA increased to ≥5.0 ng/mL. End points included time off treatment, PSA nadir after 9 months of ADT, serum testosterone and dihydrotestosterone levels, and time to castrate-resistant prostate cancer (rising PSA while testosterone levels remain <50 ng/mL).
  
  
  RESULTS
  There were 87 evaluable patients: 49 dutasteride, 38 placebo. In total, 80 patients completed one treatment cycle: 45 dutasteride, 35 placebo. The median time off treatment for patients reaching ≥5 ng/mL was 18.6 and 16.7 months for dutasteride and placebo, respectively (p = 0.7600). The median PSA nadir at 9 months was 0.1 and 0.075 ng/mL, respectively (p = 0.4486). There were no cases of androgen-independent prostate cancer. Our study limitations include its short duration with only one treatment cycle evaluated.
  
  
  CONCLUSIONS
  This small-scale Phase II randomized controlled trial showed no benefit to the addition of dutasteride to an IAD regimen.
authors.affiliation: Division of Urology, Sunnybrook Health Sciences Centre, Toronto, ON;
authors.forename: Laurence
authors.initials: L
authors.lastname: Klotz
authors.affiliation: Department of Radiation Oncology, Centre Hospitalier de Universitaire de Sherbrooke, Sherbrooke, QC;
authors.forename: Abdenour
authors.initials: A
authors.lastname: Nabid
authors.affiliation: Departments of Medicine and Urology, University of Washington Seattle Cancer Care Alliance, Seattle, WA;
authors.forename: Celestia
authors.initials: C
authors.lastname: Higano
authors.affiliation: Department of Medicine, Oregon Health Sciences University, Portland, OR;
authors.forename: Chris
authors.initials: C
authors.lastname: Ryanm
authors.affiliation: Division of Urology, Sunnybrook Health Sciences Centre, Toronto, ON;
authors.forename: Marlene
authors.initials: M
authors.lastname: Kebabdjian
authors.affiliation: Division of Urology, London Health Sciences Centre, London, ON.
authors.forename: Joseph
authors.initials: J
authors.lastname: Chin