A phase III comparison of two toremifene doses to tamoxifen in postmenopausal women with advanced breast cancer

Efficacy and safety of toremifene 60 and 240mg daily (TOR60 and TOR240) are compared to40 mg tamoxifen daily (TAM40) in postmenopausal womenwith advanced estrogen receptor (ER) positive or ERunknown breast cancer. The study is randomized andopen label in three parallel groups. Primary efficacyvariables are response rate and time to progression.WHO and ECOG criteria were used for measurableand nonmeasurable disease assessment, respectively. Safety was reportedaccording to WHO criteria. Altogether 463 patients wererandomized (157 to TOR60, 157 to TOR240, and149 to TAM40). By data cut-off, after 20.5months median follow-up time, over 70% of thepatients had experienced disease progression. Response rates are20.4%, 28.7%, and 20.8% in TOR60, TOR240, andTAM40, respectively. TOR60 and TAM40 show statistically equivalentefficacy and the difference between TOR240 and TAM40is not significant (P=0.112). Median timesto progression are 4.9 (TOR60), 6.1 (TOR240), and5.0 (TAM40) months and the corresponding hazard ratios(TAM:TOR) 1.015 and 1.124. Again, TOR60 and TAM40are statistically equivalent and the difference between TOR240and TAM40 is not significant (P=0.374).All treatments were well tolerated. As a conclusion,TOR60 and TAM40 show equivalent clinical efficacy andtolerability. The higher dose of toremifene slightly butnot statistically significantly improves response rate and timeto progression. In postmenopausal women, toremifene 60 mgdaily is an effective and safe treatment ofadvanced ER-positive or ER-unknown breast cancer.