The evidence supporting this protocol is provided by two multicentre international randomised, double-blind trials involving 1021 patients comparing anastrozole with tamoxifen alone as first-line therapy for advanced breast cancer in postmenopausal women.r
Between February 1996 and July 1998, 340 patients were randomised to receive anastrozole 1 mg daily and 328 patients were randomised to receive tamoxifen 20 mg daily in the TARGET trial. Between August 1995 and July 1998, 171 patients were randomised to receive anastrozole 1 mg daily and 182 patients were randomised to receive tamoxifen 20 mg daily in the North American trial.r
The primary objectives were time to treatment progression (TTP), objective response (OR) rate, and tolerability and secondary objectives were time to treatment failure (TTF), response duration, and clinical benefit duration.r
Efficacy
After a median follow-up of 18.2 months, anastrozole was at least equivalent to tamoxifen in terms of median TTP (8.5 vs 7.0 months). In a retrospective subgroup analysis, anastrozole was superior to tamoxifen with respect to TTP (10.7 vs 6.4 months, p = 0.022) in patients with oestrogen and/or progesterone receptor positive tumours.r.
29.0% of anastrozole and 27.1% of tamoxifen patients achieved either a complete response (CR) or a partial response (PR). Clinical benefit rates were 57.1% and 52.0% for anastrozole and tamoxifen, respectively.r
Kaplan–Meier plot of time to progression in patients receiving anastrozole 1 mg or tamoxifen 20 mg once daily.
© Cancer 2001
Kaplan–Meier probability of time to progression in patients receiving anastrozole 1 mg or tamoxifen 20 mg once daily—subgroup of patients with ER+ and/or PgR+ tumors.
© Cancer 2001
Toxicity
Both anastrozole and tamoxifen were well tolerated. Anastrozole led to significantly fewer venous thromboembolic (P = 0.043; not adjusted for multiple comparisons) events, and vaginal bleeding was reported in fewer patients treated with anastrozole than with tamoxifen.r
Toxicityr
© Cancer 2001