Phase III randomized trial of toremifene vs tamoxifen in hormonodependant advanced breast cancer. [Clinical evaluation of NK 622 (toremifene citrate) in advanced or recurrent breast cancer--a comparative study by a double blind method with tamoxifen]. A phase III comparison of two toremifene doses to tamoxifen in postmenopausal women with advanced breast cancer. Eastern European Study Group. Randomized comparison of tamoxifen and two separate doses of toremifene in postmenopausal patients with metastatic breast cancer. Meta-analysis of trials comparing toremifene with tamoxifen and factors predicting outcome of antiestrogen therapy in postmenopausal women with breast cancer. Toremifene and tamoxifen in advanced breast cancer--a double-blind cross-over trial. Comparison of toremifene and tamoxifen in post-menopausal patients with advanced breast cancer: a randomized double-blind, the 'nordic' phase III study.
Efficacy and safety of toremifene (TOR) 60 mgs/dayly/o.r. was compared with tamoxifen (TAM) 40 mgs/dayly/o.r. in a group of postmenopausal women with advanced breast cancer, without previous systemic therapy for advanced breast cancer.
                The study was a prospective double-blind randomized trial. All treated patients presented with positive estrogen receptors. Main end points were response rates, toxicity profile analysis, time to progression and survival. WHO and ECOG criteria were employed for response evaluation while toxicity was assesed according to WHO guidelines. Curves were constructed by means of Kaplan-Meier methodology and were compared by means of log-rank test.
                From January 1996 to January 1999 a total of 217 patients were included in the study (106 in the TOR branch and 111 in the TAM arm). Both groups of patients were homogeneous regarding the main prognostic factors. A response rate of 64% (68/106) was observed in the TOR group as compared with a 52% (58/111) in the TAM group. Median times to progression and overall survival were not significantly different. A lower incidence of undesirable effects was apreciated in the TOR arm.
                Our data suggest that TOR is an efficient and well-tolerated agent for the therapy of postmenopausal women with hormonal positive receptors advanced breast cancer, and must be considered an alternative to TAM as first line therapy for ER+ advanced breast cancer patients and as well as an adjuvant treatment. Efficacy and safety of NK 622 (toremifene citrate) were compared with tamoxifen (TAM) by a double blind test in patients with advanced or recurrent breast cancer. NK 622 and TAM were given orally for 12 weeks or more at daily doses of 40 and 20 mg/body, respectively. Eligible cases in NK622 and TAM groups were both 57 patients. No significant difference was observed in patient characteristics between either group. Response rates were 26.3% (8 CR and 7 PR, 15/57) in the NK 622 group and 28.1% (3 CR and 13 PR, 16/57) in the TAM group. Median values of duration to onset of CR were 91 days in the NK 622 group and 169 days in the TAM group. The duration was significantly shorter with the NK 622 group. Median duration of efficacy in CR and PR cases was 155 days in the NK 622 group and 154.5 days in the TAM group. Adverse effects were encountered in 7 patients (12.3%) of each of the 2 groups. The side effects were fatigue, hot flush, WBC decrease, abnormal values in liver function tests, etc. in the NK 622 group and anorexia, nausea, eruption, feeling of warmth, sweating, dry mouth, dizziness, abnormal values in liver function tests, etc. in the TAM group. Administration was discontinued in one patient with eruption and another patient with abnormal values of liver function tests in the TAM group, while there was no such case in the NK 622 group. Including the discontinued cases, the side effects were moderate and reversible in both groups. The patients in whom a drug was determined as useful or more numbered 24/57 (42.1%) in the NK 622 group and 23/57 (40.4%) in the TAM group. There was not significant difference between the 2 groups in the above results except the duration to onset of CR. From these results, NK 622 is expected to show comparable efficacy, safety, and usefulness in patients undergoing TAM treatment for advanced or recurrent breast cancer. Efficacy and safety of toremifene 60 and 240 mg daily (TOR60 and TOR240) are compared to 40 mg tamoxifen daily (TAM40) in postmenopausal women with advanced estrogen receptor (ER) positive or ER unknown breast cancer. The study is randomized and open label in three parallel groups. Primary efficacy variables are response rate and time to progression. WHO and ECOG criteria were used for measurable and nonmeasurable disease assessment, respectively. Safety was reported according to WHO criteria. Altogether 463 patients were randomized (157 to TOR60, 157 to TOR240, and 149 to TAM40). By data cut-off, after 20.5 months median follow-up time, over 70% of the patients had experienced disease progression. Response rates are 20.4%, 28.7%, and 20.8% in TOR60. TOR240, and TAM40, respectively. TOR60 and TAM40 show statistically equivalent efficacy and the difference between TOR240 and TAM40 is not significant (P = 0.112). Median times to progression are 4.9 (TOR60), 6.1 (TOR240), and 5.0 (TAM40) months and the corresponding hazard ratios (TAM:TOR) 1.015 and 1.124. Again, TOR60 and TAM40 are statistically equivalent and the difference between TOR240 and TAM40 is not significant (P = 0.374). All treatments were well tolerated. As a conclusion, TOR60 and TAM40 show equivalent clinical efficacy and tolerability. The higher dose of toremifene slightly but not statistically significantly improves response rate and time to progression. In postmenopausal women, toremifene 60 mg daily is an effective and safe treatment of advanced ER-positive or ER-unknown breast cancer. To perform a randomized three-arm comparison of tamoxifen (TAM; 20 mg/d) and two separate doses of toremifene (TOR; 60 mg/d [TOR60] and 200 mg/d [TOR200]) in postmenopausal patients with hormone receptor-positive or -unknown metastatic breast cancer.
                Six hundred forty-eight patients with hormone receptor-positive or -unknown metastatic breast cancer were randomly assigned to receive TAM (n = 215), TOR60 (n = 221), or TOR200 (n = 212).
                The combined response rates (by intent to treat) were as follows;: TAM, 44%; TOR60, 50%; and TOR200, 48%. Complete and partial response rates were as follows: TAM, 19%; TOR60, 21%, and TOR200, 23% (not statistically different). Median times to progression and overall survival were not significantly different. Adverse events (lethal, serious but nonlethal, and important but non-life-threatening) were similar in all three arms, except that patients in the TOR200 arm had a statistically significantly increased rate of nausea (37% v 26% and 26% for TOR200, TAM, and TOR60, respectively; P = .027). Quality-of-life assessments were not different among the three arms.
                The activity, toxicity, and side effects of TOR in postmenopausal women with hormone receptor-positive or -unknown metastatic breast cancer are similar if not equivalent to those of TAM. We detected no clear evidence of a dose-response effect for TOR. TOR60 is an effective and safe agent for the treatment of postmenopausal women with hormone receptor-positive metastatic breast cancer and can be considered an alternative to TAM as first-line treatment for such patients. Meta-analysis of all clinical data was conducted to compare toremifene 40-60 mg/day (TOR) with tamoxifen 20-40 mg/day (TAM) in postmenopausal women with estrogen receptor (ER) positive or ER unknown advanced breast cancer and assess factors predicting treatment outcome. Data from five randomized parallel group studies (all studies) were combined. Efficacy variables were the response rate in all studies and also the time to treatment failure and survival in the three major studies (pivotal studies). Of the 1421 patients, 725 received TOR and 696 TAM. Response rates were 24.0% and 25.3%, respectively (p = 0.675) with 95% confidence interval (95% CI) for the difference -5.3 to 3.4. Of the 1157 patients in the pivotal studies, 75% had progressed and 50% expired. Median treatment times were 4.9 months in TOR and 5.3 months in TAM groups (p = 0.762, hazard ratio 0.98 with 95% CI 0.87-1.11). Median survival times were 31.0 (TOR) and 33.1 (TAM) months (p = 0.758, hazard ratio 0.98 with 95% CI 0.83-1.15). All results are consistent with the criteria of statistical equivalence between TOR and TAM. More patients in TAM (20%) than in TOR (14%, p = 0.007) discontinued the treatment prematurely but overall the treatments were well tolerated. As the treatments were equally effective all data were analyzed together for predictive factors. High tumor ER concentration, long disease free time, soft tissue metastases, few metastatic sites, and good performance status all independently predicted longer survival (p<0.001). Previous adjuvant tamoxifen predicted shorter survival (p = 0.008). Objective response to treatment or disease stabilization for at least 12 months both predicted prolonged survival (p = 0.001). TOR 60 mg/day and TAM are equally effective and well tolerated in the treatment of advanced breast cancer in postmenopausal women. Probability of survival may be predicted based on patient characteristics and on the initial response to the treatment. Toremifene (TOR) is a triphenylethylene derivative related to tamoxifen (TAM). TOR has antitumor activity, not dependent on estrogen receptors, and responses with TOR have been observed in patients with progressive disease during TAM-treatment. To elucidate possible cross-resistance between these two antiestrogens, we compared their anti-tumor activity in a randomized, double-blind, cross-over study. 66 postmenopausal women with advanced estrogen receptor positive or unknown breast cancer and a median age of 63 years (range 38-82) were included. Patients were randomized to TAM 40 mg/day or TOR 240 mg/day. Treatment continued until progressive disease, when cross-over to the alternative treatment was done. The response rate with first line TOR was 29% (95% confidence limits 10-41%) and with TAM 42% (95% confidence limits 25-61%). Response rates and response durations, survival and toxicity were not significantly different between the two treatments. 44 patients progressing on first line TAM or TOR were evaluable for second line TOR or TAM treatment. As no responses were observed, the possibility of over-looking a response rate of 20% or more is less than 1%. In conclusion, this study strongly indicates that TOR and TAM are clinically cross-resistant in patients with advanced breast cancer. The study was planned to compare, in a prospective double-blind randomized trial, the efficacy and safety of toremifene (TOR) and tamoxifen (TAM) in post-menopausal patients with advanced breast cancer who have not had prior systemic therapy for advanced disease. Four hundred and fifteen post-menopausal patients with oestrogen receptor (ER)-positive or ER-unknown advanced breast cancer were randomly assigned to receive daily either 60 mg TOR or 40 mg TAM. The patients were stratified to measurable and non-measurable but evaluable groups. They were assessed for response to therapy, time to progression (TTP), time to treatment failure (TTF), response duration, overall survival and drug toxicity. Two hundred and fourteen patients were randomized into TOR and 201 into TAM treatment. The response rate (complete + partial) was 31.3% for TOR and 37.3% for TAM (P = 0.215). The 95% confidence interval (CI) for the 6% difference was -15.1% to 3.1%. The median TTP was 7.3 months for TOR and 10.2 months for TAM (P = 0.047). The 95% CI for the hazard ratio of 0.80 was 0.64-1.00. A percentage of the TOR patients (9.8%) and the TAM patients (18.9%) discontinued the treatment prematurely (P = 0.011) for various reasons. Consequently, the median TTF of 6.3 vs 8.5 months did not differ significantly (P = 0.271). The hazard ratio was 0.89 and the subsequent 95% CI 0.73-1.09. The median overall survival was 33.0 months for TOR and 38.7 months for TAM (P = 0.645). The hazard ratio was 0.94 with 95% CI of 0.73-1.22. The transient difference in TTP may be related to an imbalance in ER content of the tumours. When only patients with ER-positive tumours were considered (n = 238), no difference between two treatments was seen (P = 0.578). TAM was associated with an overall slightly higher frequency of adverse drug reactions than TOR (44.3 vs 39.3%) and a higher discontinuation rate due to these events (3.5% vs 0.9%). Treatment-emerged moderate dizziness (P = 0.026) and cataracts (P = 0.026) were more frequent among TAM than among TOR patients. In conclusion, TOR (60 mg day(-1)) and TAM (40 mg day(-1)) are equally effective and safe in the treatment of advanced post-menopausal ER-positive or ER-unknown breast cancer.
TOR and TAM are equally effective and the safety profile of the former is at least not worse than the latter in the first-line treatment of patients with advanced breast cancer. Thus, TOR may serve as a reasonable alternative to TAM when anti-oestrogens are applicable but TAM is not the preferred choice for some reason.