Phase II trials with toremifene in advanced breast cancer: a review

The antitumor activity of the new triphenylethylene drug toremifene has been studied in advanced breast cancer of postmenopausal women as first line treatment at dose levels of 20, 60, and 240 mg, and as second line or later treatment at high dose levels of 200-240 mg. The response rates (complete + partial response) have been 21% with 20 mg (14 patients), 52% with 60 mg (93 patients in three separate trials), and 68% with 240 mg (38 patients) as first line treatment. After failure on previous therapy (hormonal or chemotherapy) the response rates have been about 10% with 200 mg of toremifene (71 patients in two different trials). In patients whose disease had previously responded to tamoxifen with at least stabilization, the response rate with toremifene has been 23%; but among unselected patients, including patients progressing during adjuvant tamoxifen, the response rate (CR + PR) with toremifene in tamoxifen failures has been 3%. If long lasting (more than 5 months) stabilization of the disease is also considered, a further 20% of previously treated patients have benefitted from toremifene. The treatment has been well tolerated at all dose levels. The most reported side effects have been hot flushes (8-19%) and nausea (8%). 0-6% of patients in different trials have interrupted the treatment because of side effects.