Anastrozole (Arimidex™) versus tamoxifen as first-line therapy for advanced breast cancer in postmenopausal women: survival analysis and updated safety results

Abstract

We present an initial survival analysis and an update of the safety data of the North American and Tamoxifen or Arimidex™ Randomized Group Efficacy and Tolerability (TARGET) double-blind, randomised, multicentre studies which compared anastrozole with tamoxifen as first-line treatment in postmenopausal patients with oestrogen receptor and/or progesterone receptor-positive (ER+/PR+) or receptor-unknown advanced breast cancer (ABC). At a median follow-up of 43.7 months, 56.0% of patients in the anastrozole group and 56.1% of patients in the tamoxifen group had died. The proportion of patients dead at 2 years was 31.1 and 32.0% in the anastrozole and tamoxifen groups, respectively. In the ER+/PR+ subgroup, 55.1 and 55.9% of patients had died and median time to deaths (TTD) were 40.8 and 41.3 months in the anastrozole and tamoxifen groups, respectively. Both agents remained well tolerated, with fewer reports of vaginal bleeding (anastrozole versus tamoxifen, 1.0% versus 2.5%) and thromboembolic events (anastrozole versus tamoxifen, 5.3% versus 9.0%) in the anastrozole group versus the tamoxifen group. Hot flushes and vaginal dryness were reported marginally less in the tamoxifen group compared with the Anastrozole group. Although no improvement in survival was observed, the favourable profile of anastrozole with respect to efficacy (TTP) and tolerability [Cancer 92 (2001) 2247] support the use of anastrozole in advance of tamoxifen as the first-line therapy choice in postmenopausal women with ABC.