Toremifene, a new antiestrogenic compound, for treatment of advanced breast cancer. Phase II study.

Forty-six postmenopausal women with estrogen receptor positive advanced breast cancer were treated with the novel antiestrogen toremifene in this phase II study. The patients had no prior or concurrent hormonal or cytostatic treatment. Sixty milligrams of toremifene was given as a single daily dose for a minimum treatment period of 6 weeks. Eight patients (17%) achieved complete response, 17 (37%) partial response and 12 (26%) showed no change. The median durations of responses were 93, 66 and 24 weeks, respectively. Three patients still continue the treatment in complete response, four patients in partial response. No significant differences in response rates could be seen when related to different estrogen receptor concentrations. The treatment was well tolerated, only two patients had remarkable side-effects; one of the patients interrupted the treatment mainly because of tremor. Our conclusion is that toremifene is an effective, safe and in clinical practice easily applied choice of treatment in estrogen receptor positive advanced breast cancer.